From b05c361fbdcba59d2ef095b210d20e0eab43ea3b Mon Sep 17 00:00:00 2001
From: Woody <woody.ck.tse@gmail.com>
Date: Sat, 9 May 2026 21:07:21 +0800
Subject: [PATCH] =?UTF-8?q?revert:=20remove=20Phase=203=20YouTube=20proxy?=
 =?UTF-8?q?=20=E2=80=94=20all=207=20sub-phases?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Reverts commits 284028b through b4096d6. Phase 4 (System Audio Capture)
will replace the YouTube use case with a more versatile getDisplayMedia approach.

Removed: YouTube router, HLS proxy, YouTubeService, YouTubeInput,
YouTubeVideoPlayer, useYouTubeASR hook, all Phase 3 tests, hls.js dep,
YouTube config fields, YouTube README/plan sections.

Modified files restored to pre-Phase-3 state: LTTPage (no source toggle),
api.ts (no YouTube extract), types (no YouTube types), config.py (no
youtube fields), main.py (no YouTube router), requirements.txt (no yt-dlp),
.env.example (no YouTube vars), package.json (no hls.js).

Relevant Phase 2 code preserved: ws_asr.py (unchanged), useVideoASR,
VideoPlayer, VideoUpload, QueryInput, Full Transcript.
---
 .plans/phase3_youtube_proxy_plan.md           | 406 ++++++---------
 README.md                                     |  38 --
 backend/.env.example                          |   5 -
 backend/app/core/config.py                    |   5 -
 backend/app/main.py                           |   3 +-
 backend/app/models/youtube.py                 |  28 -
 backend/app/routers/youtube.py                | 123 -----
 backend/app/services/hls_proxy.py             |  75 ---
 backend/app/services/youtube_service.py       | 148 ------
 .../acceptance/test_acceptance_phase3_live.py |  97 ----
 .../test_acceptance_phase3_youtube.py         | 148 ------
 backend/app/test/test_integration_phase3.py   | 361 -------------
 backend/app/test/test_phase3_config.py        | 177 -------
 backend/app/test/test_phase3_hls_proxy.py     | 337 -------------
 .../app/test/test_phase3_youtube_extract.py   | 477 ------------------
 backend/requirements.txt                      |   1 -
 development_plan.md                           |  45 +-
 frontend/package-lock.json                    |   7 -
 frontend/package.json                         |   1 -
 frontend/src/components/YouTubeInput.tsx      | 110 ----
 .../src/components/YouTubeVideoPlayer.tsx     | 207 --------
 frontend/src/hooks/useYouTubeASR.ts           | 178 -------
 frontend/src/lib/api.ts                       |   7 +-
 frontend/src/lib/queries.tsx                  |  10 +-
 frontend/src/pages/LTTPage.tsx                | 167 ++----
 .../test_phase3_LTTPage_integration.test.tsx  | 197 --------
 .../test/test_phase3_YouTubeInput.test.tsx    | 149 ------
 .../test_phase3_YouTubeVideoPlayer.test.tsx   | 168 ------
 .../test/test_phase3_useYouTubeASR.test.ts    | 179 -------
 frontend/src/types/index.ts                   |  23 -
 30 files changed, 187 insertions(+), 3690 deletions(-)
 delete mode 100644 backend/app/models/youtube.py
 delete mode 100644 backend/app/routers/youtube.py
 delete mode 100644 backend/app/services/hls_proxy.py
 delete mode 100644 backend/app/services/youtube_service.py
 delete mode 100644 backend/app/test/acceptance/test_acceptance_phase3_live.py
 delete mode 100644 backend/app/test/acceptance/test_acceptance_phase3_youtube.py
 delete mode 100644 backend/app/test/test_integration_phase3.py
 delete mode 100644 backend/app/test/test_phase3_config.py
 delete mode 100644 backend/app/test/test_phase3_hls_proxy.py
 delete mode 100644 backend/app/test/test_phase3_youtube_extract.py
 delete mode 100644 frontend/src/components/YouTubeInput.tsx
 delete mode 100644 frontend/src/components/YouTubeVideoPlayer.tsx
 delete mode 100644 frontend/src/hooks/useYouTubeASR.ts
 delete mode 100644 frontend/src/test/test_phase3_LTTPage_integration.test.tsx
 delete mode 100644 frontend/src/test/test_phase3_YouTubeInput.test.tsx
 delete mode 100644 frontend/src/test/test_phase3_YouTubeVideoPlayer.test.tsx
 delete mode 100644 frontend/src/test/test_phase3_useYouTubeASR.test.ts

diff --git a/.plans/phase3_youtube_proxy_plan.md b/.plans/phase3_youtube_proxy_plan.md
index f009a92..81b326f 100644
--- a/.plans/phase3_youtube_proxy_plan.md
+++ b/.plans/phase3_youtube_proxy_plan.md
@@ -1,15 +1,15 @@
 # Phase 3: YouTube Live Stream Proxy → ASR → RAG — Implementation Plan
 
 **Created:** 2026-05-09
-**Updated:** 2026-05-09 (Phase 3 complete — all 7 sub-phases done)
-**Status:** ✅ Complete
+**Updated:** 2026-05-09 (user decisions incorporated)
+**Status:** Planning
 **Depends on:** Phase 1 (Complete), Phase 2 (Complete)
 
 ---
 
 ## 1. Overview
 
-Phase 3 adds YouTube live stream (and VOD) playback as an alternative to file upload. User pastes a YouTube URL → backend extracts stream URLs via yt-dlp (separate video-only + audio-only for VODs; combined HLS for live) → backend proxies HLS manifests and .ts segments (zero re-encoding) → frontend plays video in `<video>` via hls.js, routes audio through hidden `<audio>` element → AudioContext.createMediaElementSource(audioElement) → existing ASR pipeline (WebSocket → DashScope) → transcript flows into QueryInput → Phase 1 RAG pipeline.
+Phase 3 adds YouTube live stream (and VOD) playback as an alternative to file upload. User pastes a YouTube URL → backend extracts separate video-only and audio-only HLS streams via yt-dlp → backend proxies HLS manifests and .ts segments (zero re-encoding) → frontend plays video in `<video>` via hls.js, routes audio through hidden `<audio>` element → AudioContext.createMediaElementSource(audioElement) → existing ASR pipeline (WebSocket → DashScope) → transcript flows into QueryInput → Phase 1 RAG pipeline.
 
 **Same code works identically for live streams and VODs.**
 
@@ -20,16 +20,14 @@ YouTube's official iframe player does not expose the audio track to Web Audio AP
 ### Audio Routing
 
 ```
-YouTube HLS stream (combined video+audio for live; separate tracks for VOD)
-  → hls.js loads into <video> (muted) and hidden <audio> element
+YouTube HLS audio-only stream
+  → hls.js loads into hidden <audio> element
   → AudioContext.createMediaElementSource(audioElement)
   → ScriptProcessorNode (Float32 PCM)
   → WebSocket → FastAPI → DashScope realtime ASR
   → transcript → QueryInput
 ```
 
-Note: For VODs, separate video-only and audio-only tracks are used. For live streams, YouTube provides combined formats only — the same HLS manifest URL is used for both elements; hls.js demuxes them independently.
-
 ### Integration With Existing Pipeline
 
 This phase reuses the existing ASR infrastructure entirely:
@@ -57,65 +55,51 @@ This phase reuses the existing ASR infrastructure entirely:
 
 ## 3. Sub-Phases
 
-### Phase 3.1 — Configuration & Infrastructure Setup ✅ Complete
+### Phase 3.1 — Configuration & Infrastructure Setup (0.5 day)
 
 Add config fields, install dependencies, create skeletons, register router.
 
-**Test:** `test_phase3_config.py` (11 tests)
+**Test:** `test_phase3_config.py`
 
 **Tasks:**
-| # | Task | File | Status |
-|---|------|------|--------|
-| 3.1.1 | Add config fields: `youtube_proxy_enabled`, `yt_dlp_timeout`, `yt_dlp_cache_ttl` | `core/config.py` | Done |
-| 3.1.2 | Update `.env.example` | `.env.example` | Done |
-| 3.1.3 | Add deps: `yt-dlp>=2024.0.0` to `requirements.txt`, `hls.js@^1.5.0` to `package.json` | `requirements.txt`, `package.json` | Done |
-| 3.1.4 | Create `models/youtube.py` — `YouTubeExtractRequest`, `YouTubeStreamResponse`, `StreamFormat` | `models/youtube.py` | Done |
-| 3.1.5 | Create `services/youtube_service.py` stub | `services/youtube_service.py` | Done |
-| 3.1.6 | Create `services/hls_proxy.py` stub | `services/hls_proxy.py` | Done |
-| 3.1.7 | Create `routers/youtube.py` stub: `POST /youtube/extract`, `GET /youtube/proxy/{stream_type}/{path}` | `routers/youtube.py` | Done |
-| 3.1.8 | Register router in `main.py` | `main.py` | Done |
-| 3.1.9 | Write and pass `test_phase3_config.py` | `app/test/` | Done (11/11 pass) |
+| # | Task | File |
+|---|------|------|
+| 3.1.1 | Add config fields: `youtube_proxy_enabled`, `yt_dlp_timeout`, `yt_dlp_cache_ttl` | `core/config.py` |
+| 3.1.2 | Update `.env.example` | `.env.example` |
+| 3.1.3 | Add deps: `yt-dlp>=2024.0.0` to `requirements.txt`, `hls.js@^1.5.0` to `package.json` | `requirements.txt`, `package.json` |
+| 3.1.4 | Create `models/youtube.py` — `YouTubeExtractRequest`, `YouTubeStreamResponse`, `StreamFormat` | `models/youtube.py` |
+| 3.1.5 | Create `services/youtube_service.py` stub | `services/youtube_service.py` |
+| 3.1.6 | Create `services/hls_proxy.py` stub | `services/hls_proxy.py` |
+| 3.1.7 | Create `routers/youtube.py` stub: `POST /youtube/extract`, `GET /youtube/proxy/{stream_type}/{path}` | `routers/youtube.py` |
+| 3.1.8 | Register router in `main.py` | `main.py` |
+| 3.1.9 | Write and pass `test_phase3_config.py` | `app/test/` |
 
 ---
 
-### Phase 3.2 — YouTube URL Extraction Backend ✅ Complete
+### Phase 3.2 — YouTube URL Extraction Backend (0.5 day)
 
-yt-dlp wrapper service that extracts stream URLs and formats. Returns proxy-wrapped URLs pointing back to our HLS proxy.
+yt-dlp wrapper service that extracts separate video-only and audio-only HLS URLs. Returns proxy-wrapped URLs pointing back to our HLS proxy.
 
-**Test:** `test_phase3_youtube_extract.py` (18 tests)
+**Test:** `test_phase3_youtube_extract.py`
 
 **Acceptance Criteria:**
 - `POST /api/v1/youtube/extract` accepts `{"url": "https://www.youtube.com/watch?v=..."}`
-- Returns `{ video_id, title, is_live, video_proxy_url, audio_proxy_url, thumbnail_url, formats, error }`
-- VODs: extracts separate video-only + audio-only tracks, selects best ≤480p + highest-bitrate audio
-- Live streams: extracts combined HLS formats, uses same URL for video and audio (hls.js demuxes)
-- Upcoming/scheduled streams: returns `is_upcoming: true` with no proxy URLs
-- Invalid/private URLs: returns 200 with error field populated (yt-dlp exception caught)
-- URL expiration: in-memory cache with TTL (5 min for live, 30 min for VOD)
-- Service singleton: `@lru_cache` on `_get_youtube_service()` for cache persistence across requests
-
-**Implementation Discoveries:**
-- **No iOS client needed** — default yt-dlp works for both VOD (separate tracks) and live (combined HLS)
-- **Live streams use combined formats** — all live formats include both video+audio; same HLS URL serves both `<video>` and `<audio>` elements
-- **Format selection** (`_pick_best_video`): prefers ≤480p with HLS first, then falls back to ascending height + HLS preference
-- **Error response pattern**: extraction errors return HTTP 200 with `error` field (not 4xx); the API call itself succeeds but YouTube returned an error
-- **Proxy URL construction** (`_build_proxy_url`): URL-encodes upstream URL into `/api/v1/youtube/proxy/manifest.m3u8?url=<encoded>`
-
-**Real-URL Verification:**
-```
-VOD:  https://www.youtube.com/watch?v=5bF3tkO5jAA → 24 formats, separate video+audio ✓
-Live: https://www.youtube.com/watch?v=fN9uYWCjQaw → 6 combined formats, same URL ✓
-```
+- Returns `{ video_id, title, is_live, video_proxy_url, audio_proxy_url, thumbnail_url }`
+- VODs: extracts ~2–10 formats, returns best video+audio pair
+- Live streams: uses `ios` client for HLS, returns current live edge
+- Upcoming/scheduled streams: returns `is_upcoming: true` with scheduled start time
+- Invalid/private URLs: returns clear error
+- URL expiration: caches extraction result with TTL (5 min for live, 30 min for VOD)
 
 **Tasks:**
-| # | Task | File | Status |
-|---|------|------|--------|
-| 3.2.1 | Write tests first | `app/test/test_phase3_youtube_extract.py` | Done |
-| 3.2.2 | Implement `YouTubeService.extract_streams()` — yt-dlp wrapper with format selection | `services/youtube_service.py` | Done |
-| 3.2.3 | Implement `YouTubeService._select_best_formats()` + `_pick_best_video()` — separate video/audio from format list, prefer ≤480p, combined fallback | `services/youtube_service.py` | Done |
-| 3.2.4 | Implement format URL caching with TTL (live 5 min, VOD 30 min) | `services/youtube_service.py` | Done |
-| 3.2.5 | Implement `POST /api/v1/youtube/extract` route with response model + error handling | `routers/youtube.py` | Done |
-| 3.2.6 | Run tests → pass → verified with real URLs | — | Done (82/82 pass) |
+| # | Task | File |
+|---|------|------|
+| 3.2.1 | Write tests first | `app/test/test_phase3_youtube_extract.py` |
+| 3.2.2 | Implement `YouTubeService.extract_streams()` — yt-dlp wrapper with format selection | `services/youtube_service.py` |
+| 3.2.3 | Implement `YouTubeService._select_best_formats()` — separate video/audio from format list, prefer ≤480p | `services/youtube_service.py` |
+| 3.2.4 | Implement format URL caching with TTL | `services/youtube_service.py` |
+| 3.2.5 | Implement `POST /api/v1/youtube/extract` route | `routers/youtube.py` |
+| 3.2.6 | Run tests → pass → commit | — |
 
 ---
 
@@ -147,165 +131,108 @@ Proxy service that rewrites HLS manifests and proxies .ts segments. StreamingRes
 
 ---
 
-### Phase 3.4 — Frontend: YouTube Input + Video Player ✅ Complete
+### Phase 3.4 — Frontend: YouTube Input + Video Player (1 day)
 
-URL input component and hls.js-based video player. Two media elements: visible `<video muted>` and hidden `<audio>` (for Web Audio API routing).
+URL input component and hls.js-based video player. Two hidden media elements: visible `<video>` (video-only, muted) and hidden `<audio>` (audio-only, for Web Audio API routing).
 
-**Tests:** `test_phase3_YouTubeInput.test.tsx` (7 tests), `test_phase3_YouTubeVideoPlayer.test.tsx` (9 tests)
+**Tests:** `test_phase3_YouTubeInput.test.tsx`, `test_phase3_YouTubeVideoPlayer.test.tsx`
 
 **Acceptance Criteria:**
-- `YouTubeInput` accepts URL, validates format (youtube.com/watch, youtu.be, /live/, /shorts/), shows loading/error states
+- `YouTubeInput` accepts URL, validates format, shows loading/error states
 - `YouTubeVideoPlayer` uses `forwardRef<HTMLVideoElement>` (same pattern as `VideoPlayer`)
-- Video HLS loaded via hls.js into `<video muted>` element, quality capped ≤480p via `capLevelsTo480()`
-- Audio HLS loaded via hls.js into hidden `<audio>` element, exposed via `onAudioReady` callback
+- Video HLS loaded via hls.js into `<video muted>` element at 360p–480p (auto-best ≤ 480p)
+- Audio HLS loaded via hls.js into hidden `<audio>` element
+- Audio element exposes ref for parent to connect to AudioContext
 - Thumbnail displayed as placeholder until user presses play; video element replaces it on play
 - Video does NOT auto-play on load (waits for manual user play)
 - Loading spinner, error overlay, "LIVE" badge for live streams
-- hls.js: dynamic `import('hls.js')` with fallback if not supported (SSR-safe)
+- **HLS error recovery**: on `hls.js` fatal error → re-extract stream URL → retry up to 3× → show "Service unavailable" on exhaustion
 - CrossOrigin="anonymous" on both elements (required for AudioContext graph)
 - No quality selector (low resolution only, sufficient for reference video)
 
-**Implementation Notes:**
-- hls.js installed as npm dependency (was already in package.json from Phase 3.1)
-- YouTubeVideoPlayer uses `useImperativeHandle`-style callback ref for audio element exposure
-- Quality capping: on `MANIFEST_PARSED`, sets `hls.autoLevelCapping` to highest level with height ≤ 480
-- Thumbnail overlay: absolute-positioned `<img>` that hides on video `onPlay` event
-
 **Tasks:**
-| # | Task | File | Status |
-|---|------|------|--------|
-| 3.4.1 | Write tests first | `src/test/test_phase3_YouTubeInput.test.tsx`, `src/test/test_phase3_YouTubeVideoPlayer.test.tsx` | Done |
-| 3.4.2 | Add YouTube types to `types/index.ts` | `types/index.ts` | Done |
-| 3.4.3 | Add API functions to `lib/api.ts` | `lib/api.ts` | Done |
-| 3.4.4 | Add TanStack Query hooks to `lib/queries.tsx` | `lib/queries.tsx` | Done |
-| 3.4.5 | Create `components/YouTubeInput.tsx` — URL input, validation, loading/error states | `components/YouTubeInput.tsx` | Done |
-| 3.4.6 | Create `components/YouTubeVideoPlayer.tsx` — hls.js dual-element player, forwardRef, onAudioReady | `components/YouTubeVideoPlayer.tsx` | Done |
-| 3.4.7 | Run tests → pass → commit | — | Done (16/16 pass) |
+| # | Task | File |
+|---|------|------|
+| 3.4.1 | Write tests first | `src/test/test_phase3_YouTubeInput.test.tsx`, `src/test/test_phase3_YouTubeVideoPlayer.test.tsx` |
+| 3.4.2 | Add YouTube types to `types/index.ts` | `types/index.ts` |
+| 3.4.3 | Add API functions to `lib/api.ts` | `lib/api.ts` |
+| 3.4.4 | Add TanStack Query hooks to `lib/queries.tsx` | `lib/queries.tsx` |
+| 3.4.5 | Create `components/YouTubeInput.tsx` — URL input, validation, loading/error states | `components/YouTubeInput.tsx` |
+| 3.4.6 | Create `components/YouTubeVideoPlayer.tsx` — hls.js dual-element player, forwardRef | `components/YouTubeVideoPlayer.tsx` |
+| 3.4.7 | Run tests → pass → commit | — |
 
 ---
 
-### Phase 3.5 — Integration: YouTube → ASR Pipeline ✅ Complete
+### Phase 3.5 — Integration: YouTube → ASR Pipeline (1 day)
 
-Wire YouTube audio output into existing ASR pipeline. Creates `useYouTubeASR` hook (adapted from `useVideoASR`) and integrates YouTube components into `LTTPage` with a source toggle.
+Wire YouTube audio output into existing ASR pipeline. The key challenge: `useVideoASR` currently captures from `<video>` element; we need it to capture from the `<audio>` element loaded by hls.js.
 
-**Tests:** `test_phase3_useYouTubeASR.test.ts` (11 tests), `test_phase3_LTTPage_integration.test.tsx` (7 tests)
+**Tests:** `test_phase3_useYouTubeASR.test.ts`, `test_phase3_LTTPage_integration.test.tsx`
 
 **Acceptance Criteria:**
-- `useYouTubeASR` hook: accepts `audioElement` + `videoElement`, sets up AudioContext graph on mount
-- AudioContext.createMediaElementSource(audioElement) → ScriptProcessorNode → WebSocket (same as useVideoASR, but audio source from `<audio>` element)
-- Play/pause/ended events on `videoElement` (user controls video, audio follows)
+- `useYouTubeASR` hook: accepts `audioElement` ref, sets up AudioContext graph on mount
+- AudioContext.createMediaElementSource(audioElement) → ScriptProcessorNode → WebSocket
 - Auto-starts ASR on play, stops on pause/end (same lifecycle as `useVideoASR`)
-- Transcript flows into QueryInput (same `onFinalTranscript` + `partialTranscript` callbacks)
-- QueryInput remains editable during streaming — user can type corrections while ASR appends (already worked, no changes needed)
+- Transcript flows into QueryInput (same `onFinalTranscript` callback)
+- QueryInput remains editable during streaming — user can type corrections while ASR appends
 - "Full Transcript" button hidden when YouTube source is active
-- Source toggle: "Upload" / "YouTube" tabs at top of upper-left panel
-- Switching between "Upload" and "YouTube" sources clears previous YouTube state
-- Upload video state preserved when switching to YouTube and back
-
-**Implementation Notes:**
-- Both `useVideoASR` and `useYouTubeASR` initialized unconditionally at top of LTTPage
-- Hooks gracefully handle null elements (AudioContext setup aborts early if element is null)
-- Unified `asr` variable: `const asr = source === 'youtube' ? youtubeASR : uploadASR`
-- Source toggle uses `Upload`/`Youtube` icons from lucide-react, blue active / gray inactive state
-- `QueryInput.tsx` — zero changes needed (already supports `partialText` + `value` from any source)
-- `YouTubeVideoPlayer` exposes audio element via `onAudioReady` callback → LTTPage wires to `useYouTubeASR`
+- Switching between "Upload" and "YouTube" sources clears previous state
 
 **Tasks:**
-| # | Task | File | Status |
-|---|------|------|--------|
-| 3.5.1 | Write tests first | `src/test/test_phase3_useYouTubeASR.test.ts` | Done (11 tests) |
-| 3.5.2 | Create `hooks/useYouTubeASR.ts` | `hooks/useYouTubeASR.ts` | Done |
-| 3.5.3 | Update `QueryInput.tsx` | `components/QueryInput.tsx` | Done (no-op: already works) |
-| 3.5.4 | Update `LTTPage.tsx` — source toggle, wire components | `pages/LTTPage.tsx` | Done |
-| 3.5.5 | Create LTTPage integration test | `src/test/test_phase3_LTTPage_integration.test.tsx` | Done (7 tests) |
-| 3.5.6 | Run tests → pass → commit | — | Done (189/189 pass) |
+| # | Task | File |
+|---|------|------|
+| 3.5.1 | Write tests first | `src/test/test_phase3_useYouTubeASR.test.ts` |
+| 3.5.2 | Create `hooks/useYouTubeASR.ts` — adapted from `useVideoASR.ts`, targets `<audio>` element | `hooks/useYouTubeASR.ts` |
+| 3.5.3 | Update `QueryInput.tsx` — accept transcript from either source | `components/QueryInput.tsx` |
+| 3.5.4 | Update `LTTPage.tsx` — add source toggle (Upload / YouTube), wire YouTubeInput + YouTubeVideoPlayer | `pages/LTTPage.tsx` |
+| 3.5.5 | Create `test_phase3_LTTPage_integration.test.tsx` | `src/test/` |
+| 3.5.6 | Run tests → pass → commit | — |
 
 ---
 
-### Phase 3.6 — Integration & Acceptance Testing ✅ Complete
+### Phase 3.6 — Integration & Acceptance Testing (1 day)
 
-**Tests:** `test_integration_phase3.py` (6 tests), `test_acceptance_phase3_youtube.py` (3 tests), `test_acceptance_phase3_live.py` (3 tests)
-
-**Integration test** (`backend/app/test/test_integration_phase3.py`):
-- `TestExtractAndProxyFlow` — full extract→proxy flow (VOD manifest, VOD segment, live manifest), cache hit verification
-- `TestProxyAfterExtract` — upstream manifest unavailable after extract → 502
-- `TestExtractDisabled` — extract returns 503 when `youtube_proxy_enabled=false`
-- Mocked yt-dlp, real FastAPI TestClient, real HLSProxyService
-
-**Acceptance test VOD** (`backend/app/test/acceptance/test_acceptance_phase3_youtube.py`):
-- Real YouTube VOD extraction and proxy verification
-- Manifest proxy → verify M3U8 structure and CORS
-- Segment proxy → follow master→variant→segment chain, verify MPEG-TS data
-- Skips gracefully if `YOUTUBE_TEST_VOD_URL` not set
-
-**Acceptance test live** (`backend/app/test/acceptance/test_acceptance_phase3_live.py`):
-- Real YouTube live extraction (is_live=True, combined formats)
-- Live manifest proxy → verify no #EXT-X-ENDLIST
-- Cache refresh verification (same video_id on re-extract)
-- Skips gracefully if `YOUTUBE_TEST_LIVE_URL` not set or stream offline
-
-**How to run acceptance tests:**
-```bash
-cd backend && YOUTUBE_TEST_VOD_URL="https://www.youtube.com/watch?v=5bF3tkO5jAA" \
-  YOUTUBE_TEST_LIVE_URL="https://www.youtube.com/watch?v=fN9uYWCjQaw" \
-  python -m pytest app/test/acceptance/test_acceptance_phase3_youtube.py \
-    app/test/acceptance/test_acceptance_phase3_live.py -v -m acceptance
-```
+**Tests:** `test_integration_phase3.py`, `test_acceptance_phase3_youtube.py`, `test_acceptance_phase3_live.py`
 
 **Tasks:**
-| # | Task | Status |
-|---|------|--------|
-| 3.6.1 | Integration test (mocked yt-dlp, real httpx + HLSProxyService) | Done (6 tests) |
-| 3.6.2 | Acceptance: real YouTube VOD → extract → proxy | Done (3 tests) |
-| 3.6.3 | Acceptance: real YouTube live → extract → proxy | Done (3 tests) |
-| 3.6.4 | Full regression run | Done (234 pass, 1 pre-existing config mismatch) |
-| 3.6.5 | Fix failures, commit | Done |
+| # | Task |
+|---|------|
+| 3.6.1 | Implement integration test (mocked yt-dlp, real httpx proxy + hls.js) |
+| 3.6.2 | Implement acceptance: real YouTube VOD → extract → proxy → play |
+| 3.6.3 | Implement acceptance: real YouTube live stream → extract → proxy → play + ASR |
+| 3.6.4 | Full regression run (Phase 1 + 2 + 3 tests) |
+| 3.6.5 | Fix failures, final commit |
 
 ---
 
-### Phase 3.7 — Polish & Deployment ✅ Complete
+### Phase 3.7 — Polish & Deployment (0.5 day)
 
-**Tasks:**
-
-| # | Task | Status |
-|---|------|--------|
-| 3.7.1 | PO token expiration handling | Done — `_is_po_token_error()` detection, cache invalidation, 2 tests |
-| 3.7.2 | Dockerfile — verify ffmpeg + yt-dlp | Done — ffmpeg already installed, yt-dlp in requirements.txt |
-| 3.7.3 | docker-compose.yml — verify volumes/env vars | Done — no new volumes needed (in-memory only), env vars in .env.example |
-| 3.7.4 | Verify production build | Done — `npm run build` succeeds (27s, hls chunk 523KB) |
-| 3.7.5 | README.md — YouTube feature section | Done — added after Video Q&A section |
-| 3.7.6 | development_plan.md — mark Phase 3 complete | Done — Phase 3 row added, status updated to "Phase 1-3 Complete" |
-| 3.7.7 | Final commit | In progress |
-
-**PO Token Handling:**
-- `_is_po_token_error(msg)` helper detects YouTube bot-detection / PO token errors
-- On detection: logs warning, invalidates URL cache (forces re-extract on next attempt)
-- Graceful degradation: returns error field to frontend, which can retry
-- Indicators: "sign in to confirm", "not a bot", "bot detection", "po token", "potoken"
-
-**Docker/Infra:**
-- Dockerfile already includes ffmpeg and all Python deps via requirements.txt
-- docker-compose.yml unchanged (no new volumes or env vars needed)
-- Frontend production build: 1403 modules, builds clean in ~27s
-
-**Documentation:**
-- README.md: new "YouTube Live Stream Proxy (Phase 3)" section with architecture, usage, config, limitations
-- development_plan.md: Phase 3 timeline row, Phase 3 section (backend/frontend additions, design decisions)
+| # | Task |
+|---|------|
+| 3.7.1 | Handle PO token expiration for live streams (log warning, auto-re-extract on failure) |
+| 3.7.2 | Update Dockerfile — ensure ffmpeg + yt-dlp available in container |
+| 3.7.3 | Update `docker-compose.yml` — add any new volumes/env vars |
+| 3.7.4 | Verify production build (`npm run build`, `docker compose up -d --build`) |
+| 3.7.5 | Update `README.md` — YouTube feature section |
+| 3.7.6 | Update `development_plan.md` — mark Phase 3 status |
+| 3.7.7 | Final commit |
 
 ---
 
 ## 4. Timeline
 
-| Sub-Phase | Description | Effort | Depends On | Status |
-|---|---|---|---|---|---|
-| 3.1 | Config & Infrastructure | 0.5 day | — | ✅ Complete |
-| 3.2 | YouTube URL Extraction | 0.5 day | 3.1 | ✅ Complete |
-| 3.3 | HLS Proxy Backend | 1 day | 3.1 | ✅ Complete |
-| 3.4 | Frontend Input + Player | 1 day | 3.2, 3.3 | ✅ Complete |
-| 3.5 | YouTube → ASR Integration | 1 day | 3.4 | ✅ Complete |
-| 3.6 | Integration & Acceptance | 1 day | 3.5 | ✅ Complete |
-| 3.7 | Polish & Deployment | 0.5 day | 3.6 | ✅ Complete |
-| **Total** | | **5.5 days** | | **7/7 done ✅** |
+| Sub-Phase | Description | Effort | Depends On |
+|---|---|---|---|
+| 3.1 | Config & Infrastructure | 0.5 day | — |
+| 3.2 | YouTube URL Extraction | 0.5 day | 3.1 |
+| 3.3 | HLS Proxy Backend | 1 day | 3.1 |
+| 3.4 | Frontend Input + Player | 1 day | 3.2, 3.3 |
+| 3.5 | YouTube → ASR Integration | 1 day | 3.4 |
+| 3.6 | Integration & Acceptance | 1 day | 3.5 |
+| 3.7 | Polish & Deployment | 0.5 day | 3.6 |
+| **Total** | | **5.5 days** | |
+
+3.2 (extraction) and 3.3 (proxy) can run concurrently.
 
 ---
 
@@ -338,16 +265,13 @@ YT_DLP_CACHE_TTL=300
 ## 7. Key Design Decisions
 
 | Decision | Choice | Why |
-|---|---|---|---|
+|---|---|---|
 | Streaming protocol | HLS (m3u8) | hls.js plays it natively; DASH requires dash.js |
-| yt-dlp client | **Default** (no special client) | Default extractor works for both VOD (separate tracks) and live (combined HLS); iOS client caused "No video formats" errors on some live streams |
-| Live format strategy | **Combined formats, same URL** | Live HLS formats include both video+audio; same URL for `<video>` and `<audio>` elements — hls.js demuxes each independently |
+| yt-dlp client | `ios` for live, `web` for VOD | `ios` returns HLS for live streams with 60fps support; format selector prefers ≤480p |
 | HTTP client for proxy | httpx (already present) | Streaming support via `httpx.stream()`; no new dependency |
 | Manifest rewriting | Line-by-line streaming | Live manifests can be large; never buffer whole file |
 | Audio element | Hidden `<audio>` + hls.js | `createMediaElementSource` works on `<audio>` elements |
-| URL caching | In-memory dict with TTL | yt-dlp extraction is slow (~2-5s); reuse for 5 min live, 30 min VOD |
-| Service lifetime | `@lru_cache` singleton | Cache must persist across HTTP requests for caching to work |
-| Error response | **HTTP 200 with error field** | API call succeeded; YouTube error is a content-level failure, not a protocol failure |
+| URL caching | In-memory dict with TTL | yt-dlp extraction is slow (~2-5s); reuse for 5 min |
 | **Full Transcript for YouTube** | **Disabled** | Button hidden; real-time streaming ASR only |
 | **QueryInput during streaming** | **Editable** | User can type corrections while transcript streams (same as existing ASR) |
 | **Video quality** | **360p–480p auto-best** | Low resolution sufficient for reference; no quality selector |
@@ -363,47 +287,46 @@ YT_DLP_CACHE_TTL=300
 ### New Files
 ```
 backend/
-  app/models/youtube.py                        ✅ Created (3.1)
-  app/services/youtube_service.py              ✅ Created (3.1), implemented (3.2)
-  app/services/hls_proxy.py                    ✅ Stub created (3.1)
-  app/routers/youtube.py                       ✅ Created (3.1), implemented (3.2)
-  app/test/test_phase3_config.py               ✅ Written (3.1, 11 tests)
-  app/test/test_phase3_youtube_extract.py      ✅ Written (3.2, 18 tests)
-  app/test/test_phase3_hls_proxy.py            ⏳ Pending (3.3)
-  app/test/test_phase3_hls_manifest.py         ⏳ Pending (3.3)
-  app/test/test_integration_phase3.py          ⏳ Pending (3.6)
-  app/test/acceptance/test_acceptance_phase3_youtube.py  ⏳ Pending (3.6)
-  app/test/acceptance/test_acceptance_phase3_live.py     ⏳ Pending (3.6)
+  app/models/youtube.py
+  app/services/youtube_service.py
+  app/services/hls_proxy.py
+  app/routers/youtube.py
+  app/test/test_phase3_config.py
+  app/test/test_phase3_youtube_extract.py
+  app/test/test_phase3_hls_proxy.py
+  app/test/test_phase3_hls_manifest.py
+  app/test/test_integration_phase3.py
+  app/test/acceptance/test_acceptance_phase3_youtube.py
+  app/test/acceptance/test_acceptance_phase3_live.py
 
 frontend/src/
-  components/YouTubeInput.tsx                  ✅ Created (3.4)
-  components/YouTubeVideoPlayer.tsx            ✅ Created (3.4)
-  hooks/useYouTubeASR.ts                       ✅ Created (3.5)
-  pages/LTTPage.tsx                            ✅ Updated (3.5)
-  test/test_phase3_YouTubeInput.test.tsx        ✅ Written (3.4, 7 tests)
-  test/test_phase3_YouTubeVideoPlayer.test.tsx  ✅ Written (3.4, 9 tests)
-  test/test_phase3_useYouTubeASR.test.ts        ✅ Written (3.5, 11 tests)
-  test/test_phase3_LTTPage_integration.test.tsx  ✅ Written (3.5, 7 tests)
+  components/YouTubeInput.tsx
+  components/YouTubeVideoPlayer.tsx
+  hooks/useYouTubeASR.ts
+  test/test_phase3_YouTubeInput.test.tsx
+  test/test_phase3_YouTubeVideoPlayer.test.tsx
+  test/test_phase3_useYouTubeASR.test.ts
+  test/test_phase3_LTTPage_integration.test.tsx
 ```
 
 ### Modified Files
 ```
-backend/app/core/config.py                     ✅ Done (3 fields)
-backend/.env.example                            ✅ Done (3 vars)
-backend/main.py                                 ✅ Done (router registered)
-backend/requirements.txt                        ✅ Done (yt-dlp added)
+backend/app/core/config.py                     # Add 3 config fields
+backend/.env.example                            # Add 3 env vars
+backend/main.py                                 # Register youtube router
+backend/requirements.txt                        # Add yt-dlp
 
-frontend/package.json                           ✅ Done (hls.js added)
-frontend/src/types/index.ts                     ✅ Done (3.4)
-frontend/src/lib/api.ts                         ✅ Done (3.4)
-frontend/src/lib/queries.tsx                    ✅ Done (3.4)
-frontend/src/pages/LTTPage.tsx                  ✅ Done (3.5)
-frontend/src/components/QueryInput.tsx          ✅ Done (3.5 — no-op, already compatible)
+frontend/package.json                           # Add hls.js
+frontend/src/types/index.ts                     # Add YouTube types
+frontend/src/lib/api.ts                         # Add extractYouTube(), getYouTubeProxyUrl()
+frontend/src/lib/queries.tsx                    # Add useYouTubeExtract() mutation
+frontend/src/pages/LTTPage.tsx                  # Add source toggle + YouTube components
+frontend/src/components/QueryInput.tsx          # Accept transcript from either source
 
-Dockerfile                                      ⏳ Pending (3.7)
-docker-compose.yml                              ⏳ Pending (3.7)
-README.md                                       ⏳ Pending (3.7)
-development_plan.md                             ⏳ Pending (3.7)
+Dockerfile                                      # Add yt-dlp install step
+docker-compose.yml                              # Add env vars if needed
+README.md                                       # YouTube feature section
+development_plan.md                             # Mark Phase 3 status
 ```
 
 ---
@@ -414,7 +337,7 @@ development_plan.md                             ⏳ Pending (3.7)
 |---|---|---|
 | PO Token expiration (live streams cut at 30s) | High — live streams unusable without token | Auto-re-extract on HLS failure; document cookie-based workaround; acceptance test to quantify |
 | yt-dlp extraction slow (2-5s) | Medium — poor UX on "Load Stream" click | Cache results with TTL; show progress indicator |
-| YouTube format changes break yt-dlp | Medium — sudden breakage | Pin yt-dlp version; CI test with known-good URLs; `pip install -U yt-dlp` in maintenance. **Note**: iOS client caused "No video formats" on Phoenix TV live stream; default extractor works for both tested URLs. Monitor for regressions. |
+| YouTube format changes break yt-dlp | Medium — sudden breakage | Pin yt-dlp version; CI test with known-good URLs; `pip install -U yt-dlp` in maintenance |
 | hls.js audio sync drift vs video | Low — separate streams may drift | hls.js `liveSyncDuration` keeps both near live edge; test with 10+ min streams |
 | Safari `createMediaElementSource` on HLS | Low — known Safari bug with native HLS | hls.js uses MSE, not native HLS — works around Safari bug; Chrome/Firefox unaffected |
 | YouTube ToS for proxy | Low for internal demo | Personal/enterprise internal demo is generally fine; review for public product |
@@ -425,31 +348,17 @@ development_plan.md                             ⏳ Pending (3.7)
 
 ```
 POST /api/v1/youtube/extract
-  Body: {"url": "https://www.youtube.com/watch?v=5bF3tkO5jAA"}
+  Body: {"url": "https://www.youtube.com/watch?v=dQw4w9WgXcQ"}
   Response: {
-    "video_id": "5bF3tkO5jAA",
-    "title": "《2026年稅務(修訂)(自動交換資料)條例草案》委員會會議",
+    "video_id": "dQw4w9WgXcQ",
+    "title": "Rick Astley - Never Gonna Give You Up",
     "is_live": false,
-    "is_upcoming": false,
-    "video_proxy_url": "/api/v1/youtube/proxy/manifest.m3u8?url=https%3A%2F%2Frr2---sn-jna...",
-    "audio_proxy_url": "/api/v1/youtube/proxy/manifest.m3u8?url=https%3A%2F%2Frr2---sn-jna...",
-    "thumbnail_url": "https://i.ytimg.com/vi/5bF3tkO5jAA/hqdefault.jpg",
-    "formats": [...],
-    "error": null
+    "video_proxy_url": "/api/v1/youtube/proxy/manifest.m3u8?url=...&type=video",
+    "audio_proxy_url": "/api/v1/youtube/proxy/manifest.m3u8?url=...&type=audio",
+    "thumbnail_url": "https://i.ytimg.com/vi/dQw4w9WgXcQ/hqdefault.jpg"
   }
 
-# Live stream (combined formats → same URL for video and audio)
-POST /api/v1/youtube/extract
-  Body: {"url": "https://www.youtube.com/watch?v=fN9uYWCjQaw"}
-  Response: {
-    "video_id": "fN9uYWCjQaw",
-    "is_live": true,
-    "video_proxy_url": "/api/v1/youtube/proxy/manifest.m3u8?url=...",
-    "audio_proxy_url": "/api/v1/youtube/proxy/manifest.m3u8?url=...",
-    # video_proxy_url == audio_proxy_url (same combined HLS manifest)
-  }
-
-GET /api/v1/youtube/proxy/manifest.m3u8?url=<encoded_upstream_m3u8>
+GET /api/v1/youtube/proxy/manifest.m3u8?url=<encoded_upstream_m3u8>&type=video
   → Fetches upstream manifest from googlevideo.com
   → Rewrites segment URLs:
       segment_0.ts → /api/v1/youtube/proxy/segment.ts?url=<encoded_segment_url>
@@ -470,34 +379,3 @@ GET /api/v1/youtube/proxy/segment.ts?url=<encoded_upstream_ts>
 - **hls.js API docs**: [github.com/video-dev/hls.js/blob/master/docs/API.md](https://github.com/video-dev/hls.js/blob/master/docs/API.md)
 - **hls.js low-latency live**: `lowLatencyMode: true`, `liveSyncDuration: 1.5`
 - **Existing code patterns**: `.plans/phase2_implementation_plan.md`, `backend/app/routers/video.py`, `frontend/src/hooks/useVideoASR.ts`
-
----
-
-## 12. Test Results (Current)
-
-| Suite | Tests | Status |
-|-------|-------|--------|
-| Phase 2 backend (existing) | 53 | ✅ All pass |
-| Phase 2 frontend (existing) | 51 | ✅ All pass |
-| Phase 3.1 (config) | 11 | ✅ All pass |
-| Phase 3.2 (extraction) | 18 | ✅ All pass |
-| Phase 3.3 (HLS proxy) | 22 | ✅ All pass |
-| Phase 3.4 frontend (YouTube components) | 16 | ✅ All pass |
-| Phase 3.5 frontend (ASR integration) | 18 | ✅ All pass |
-| Phase 3.6 integration | 6 | ✅ All pass |
-| Phase 3.6 acceptance (VOD) | 3 | ⏭ Skip (needs env) |
-| Phase 3.6 acceptance (live) | 3 | ⏭ Skip (needs env) |
-| Phase 3.7 | 2 tests (PO token) | ✅ All pass |
-| **Total CI** | **197** | **0 failures** |
-
-**Pre-existing failures** (not from Phase 3):
-- `test_phase1_config.py::test_config_default_values` — model version mismatch (3.5 vs 3.6)
-- `test_phase3_history_service.py` (13 errors) — missing `highlight_prompt` column
-- `test_phase3_sqlite_db.py::test_seed_default_profiles_idempotent` — stale assertion
-- `e2e/query_flow.test.tsx` (3 failures) — Phase 4 file input tests, unrelated
-
-### Real-URL Smoke Tests
-| URL | Type | Result |
-|-----|------|--------|
-| `5bF3tkO5jAA` (LegCo meeting) | VOD | 24 formats, separate video+audio ✅ |
-| `fN9uYWCjQaw` (Phoenix TV 24h) | Live | 6 combined HLS formats, same URL ✅ |
diff --git a/README.md b/README.md
index 145206d..2a4a6c0 100644
--- a/README.md
+++ b/README.md
@@ -244,44 +244,6 @@ Video → Audio → DashScope ASR → Transcript → QueryInput → RAG Pipeline
 - `ffmpeg` on server (for batch transcription)
 - `dashscope` Python package (in `requirements.txt`)
 
-### YouTube Live Stream Proxy (Phase 3)
-
-Proxy YouTube live streams and VODs through the backend, with real-time ASR transcription piped into the RAG pipeline — no file upload needed.
-
-```
-YouTube URL → yt-dlp extract → HLS manifest URLs
-                ↓
-HLS Proxy (backend): rewrites segment URLs → client fetches via proxy
-                ↓
-Frontend: hls.js plays video/audio → AudioContext → WebSocket → ASR → transcript
-```
-
-**How to use:**
-1. Toggle source from "Upload" to "YouTube" in the video panel
-2. Paste a YouTube URL (live stream or VOD)
-3. Click "Load Stream" — backend extracts streams via yt-dlp
-4. Press play — video plays via hls.js, audio feeds real-time ASR
-5. Transcript flows into QueryInput as you watch
-
-**Configuration:**
-
-| Variable | Default | Description |
-|----------|---------|-------------|
-| `YOUTUBE_PROXY_ENABLED` | `false` | Enable YouTube proxy feature |
-| `YT_DLP_TIMEOUT` | `30` | yt-dlp extraction timeout (seconds) |
-| `YT_DLP_CACHE_TTL` | `300` | Cache TTL for extracted stream info |
-
-**Requirements:**
-- `YOUTUBE_PROXY_ENABLED=true` in `.env`
-- `yt-dlp` (auto-installed via `requirements.txt`)
-- `DASHSCOPE_API_KEY` in `.env` (for ASR)
-
-**Known limitations:**
-- YouTube may require PO tokens for some videos (especially live streams) — stream may need re-extraction if tokens expire
-- Video quality limited to 480p max (no quality selector in UI — low resolution sufficient for reference viewing)
-- YouTube segment URLs expire after ~6 hours
-- "Full Transcript" button hidden for YouTube source (streaming ASR only)
-
 ### Installing ffmpeg
 
 ```bash
diff --git a/backend/.env.example b/backend/.env.example
index 71a7c32..175d7b0 100644
--- a/backend/.env.example
+++ b/backend/.env.example
@@ -36,8 +36,3 @@ ASR_REALTIME_MODEL_NAME=qwen3-asr-flash-realtime
 # Video upload (Phase 2)
 VIDEO_UPLOAD_DIR=./uploads
 MAX_VIDEO_SIZE_MB=300
-
-# YouTube Proxy (Phase 3)
-YOUTUBE_PROXY_ENABLED=true
-YT_DLP_TIMEOUT=30
-YT_DLP_CACHE_TTL=300
diff --git a/backend/app/core/config.py b/backend/app/core/config.py
index 68714db..c8dc62c 100644
--- a/backend/app/core/config.py
+++ b/backend/app/core/config.py
@@ -54,11 +54,6 @@ class Settings(BaseSettings):
     max_video_size_mb: int = 300
     supported_video_formats: list[str] = [".mp4", ".webm", ".mov", ".avi", ".mkv"]
 
-    # YouTube Proxy (Phase 3)
-    youtube_proxy_enabled: bool = True
-    yt_dlp_timeout: int = 30
-    yt_dlp_cache_ttl: int = 300  # seconds (live=5min shared; VOD=30min computed in service)
-
     # Development helpers
     model_config = {"env_file": ".env", "env_file_encoding": "utf-8"}
 
diff --git a/backend/app/main.py b/backend/app/main.py
index 41b7564..d111747 100644
--- a/backend/app/main.py
+++ b/backend/app/main.py
@@ -7,7 +7,7 @@ from fastapi import FastAPI
 from fastapi.middleware.cors import CORSMiddleware
 from fastapi.responses import FileResponse
 
-from app.routers import ingest, query, documents, prompts, history, chunks, video, ws_asr, youtube
+from app.routers import ingest, query, documents, prompts, history, chunks, video, ws_asr
 from app.core.config import get_settings
 from app.core.sqlite_db import (
     get_prompts_db,
@@ -58,7 +58,6 @@ app.include_router(history.router)
 app.include_router(chunks.router)
 app.include_router(video.router, prefix="/api/v1")
 app.include_router(ws_asr.router)
-app.include_router(youtube.router, prefix="/api/v1")
 
 _prompts_conn = get_prompts_db()
 init_prompts_db(_prompts_conn)
diff --git a/backend/app/models/youtube.py b/backend/app/models/youtube.py
deleted file mode 100644
index de30f2f..0000000
--- a/backend/app/models/youtube.py
+++ /dev/null
@@ -1,28 +0,0 @@
-"""YouTube stream extraction models (Phase 3)."""
-
-from pydantic import BaseModel
-
-
-class YouTubeExtractRequest(BaseModel):
-    url: str
-
-
-class StreamFormat(BaseModel):
-    format_id: str
-    url: str
-    resolution: str | None = None
-    is_audio_only: bool = False
-    is_video_only: bool = False
-    codec: str | None = None
-
-
-class YouTubeStreamResponse(BaseModel):
-    video_id: str
-    title: str
-    is_live: bool = False
-    is_upcoming: bool = False
-    video_proxy_url: str | None = None
-    audio_proxy_url: str | None = None
-    thumbnail_url: str | None = None
-    formats: list[StreamFormat] = []
-    error: str | None = None
diff --git a/backend/app/routers/youtube.py b/backend/app/routers/youtube.py
deleted file mode 100644
index 2bad89d..0000000
--- a/backend/app/routers/youtube.py
+++ /dev/null
@@ -1,123 +0,0 @@
-import logging
-import time
-from functools import lru_cache
-from urllib.parse import unquote
-
-import httpx
-from fastapi import APIRouter, HTTPException, Query
-from fastapi.responses import StreamingResponse
-
-from app.models.youtube import YouTubeExtractRequest, YouTubeStreamResponse, StreamFormat
-
-logger = logging.getLogger(__name__)
-router = APIRouter(tags=["youtube"])
-
-
-@lru_cache
-def _get_youtube_service():
-    from app.core.config import get_settings
-    from app.services.youtube_service import YouTubeService
-
-    s = get_settings()
-    return YouTubeService(timeout=s.yt_dlp_timeout, cache_ttl=s.yt_dlp_cache_ttl)
-
-
-@router.post("/youtube/extract", response_model=YouTubeStreamResponse)
-async def extract_youtube_stream(req: YouTubeExtractRequest):
-    from app.core.config import get_settings
-
-    settings = get_settings()
-    if not settings.youtube_proxy_enabled:
-        raise HTTPException(status_code=503, detail="YouTube proxy is disabled")
-
-    service = _get_youtube_service()
-    started = time.monotonic()
-    logger.info("youtube-extract-started url=%s", req.url)
-
-    try:
-        data = await service.extract_streams(req.url)
-    except Exception as e:
-        logger.error("youtube-extract-failed url=%s error=%s", req.url, e)
-        raise HTTPException(status_code=500, detail=str(e))
-
-    if data.get("error"):
-        logger.warning(
-            "youtube-extract-error url=%s error=%s duration=%.1fs",
-            req.url,
-            data["error"],
-            time.monotonic() - started,
-        )
-        return YouTubeStreamResponse(
-            video_id=data.get("video_id", ""),
-            title=data.get("title", ""),
-            error=data["error"],
-        )
-
-    formats = [
-        StreamFormat(
-            format_id=f.get("format_id", ""),
-            url=f.get("url", ""),
-            resolution=f.get("resolution"),
-            is_audio_only=f.get("acodec", "none") != "none" and f.get("vcodec", "none") == "none",
-            is_video_only=f.get("vcodec", "none") != "none" and f.get("acodec", "none") == "none",
-            codec=f.get("vcodec") or f.get("acodec"),
-        )
-        for f in data.get("formats", [])
-    ]
-
-    logger.info(
-        "youtube-extract-completed url=%s video_id=%s is_live=%s fmt_count=%d duration=%.1fs",
-        req.url,
-        data["video_id"],
-        data["is_live"],
-        len(formats),
-        time.monotonic() - started,
-    )
-
-    return YouTubeStreamResponse(
-        video_id=data["video_id"],
-        title=data["title"],
-        is_live=data["is_live"],
-        is_upcoming=data["is_upcoming"],
-        video_proxy_url=data.get("video_proxy_url"),
-        audio_proxy_url=data.get("audio_proxy_url"),
-        thumbnail_url=data.get("thumbnail_url"),
-        formats=formats,
-    )
-
-
-@router.get("/youtube/proxy/manifest.m3u8")
-async def proxy_manifest(url: str = Query(..., description="URL-encoded upstream HLS manifest URL")):
-    upstream_url = unquote(url)
-    from app.services.hls_proxy import HLSProxyService
-
-    client = httpx.AsyncClient(timeout=30.0)
-    req = client.build_request("GET", upstream_url)
-    upstream = await client.send(req, stream=True)
-    if upstream.status_code != 200:
-        await upstream.aclose()
-        await client.aclose()
-        raise HTTPException(status_code=502, detail="Upstream manifest unavailable")
-
-    service = HLSProxyService()
-
-    async def _stream():
-        async for line in service.rewrite_manifest(upstream_url, upstream):
-            yield line.encode("utf-8")
-        await upstream.aclose()
-        await client.aclose()
-
-    return StreamingResponse(
-        _stream(),
-        media_type="application/vnd.apple.mpegurl",
-        headers={"access-control-allow-origin": "*"},
-    )
-
-
-@router.get("/youtube/proxy/segment.ts")
-async def proxy_segment(url: str = Query(..., description="URL-encoded upstream .ts segment URL")):
-    upstream_url = unquote(url)
-    from app.services.hls_proxy import HLSProxyService
-
-    service = HLSProxyService()
-    return await service.proxy_segment(upstream_url)
diff --git a/backend/app/services/hls_proxy.py b/backend/app/services/hls_proxy.py
deleted file mode 100644
index 142c861..0000000
--- a/backend/app/services/hls_proxy.py
+++ /dev/null
@@ -1,75 +0,0 @@
-"""HLS manifest proxy service (Phase 3.3).
-
-Rewrites HLS manifests and proxies .ts segments so the browser treats
-them as same-origin, enabling Web Audio API access to the audio track.
-"""
-
-import logging
-import re
-from typing import AsyncGenerator
-from urllib.parse import quote, urljoin
-
-import httpx
-from fastapi.responses import StreamingResponse
-
-logger = logging.getLogger(__name__)
-
-
-class HLSProxyService:
-    """Streams and rewrites HLS manifests; proxies .ts segments with zero re-encoding."""
-
-    async def rewrite_manifest(self, upstream_url: str, upstream: httpx.Response) -> AsyncGenerator[str, None]:
-        base_url = upstream_url
-        async for line in upstream.aiter_lines():
-            rewritten = self._rewrite_line(line, base_url)
-            yield rewritten + "\n"
-
-    def _rewrite_line(self, line: str, base_url: str) -> str:
-        stripped = line.rstrip("\r\n")
-
-        if not stripped:
-            return stripped
-
-        if stripped.startswith("#"):
-            if stripped.startswith("#EXT-X-KEY:") and 'URI="' in stripped:
-                return self._rewrite_key_uri(stripped, base_url)
-            return stripped
-
-        if "://" in stripped:
-            absolute_uri = stripped
-        else:
-            absolute_uri = urljoin(base_url, stripped)
-
-        return self._build_proxy_url_for_uri(absolute_uri)
-
-    def _rewrite_key_uri(self, line: str, base_url: str) -> str:
-        match = re.match(r'(#EXT-X-KEY:.*URI=")(.+?)(".*)', line)
-        if not match:
-            return line
-        prefix, uri, suffix = match.group(1), match.group(2), match.group(3)
-        if "://" in uri:
-            absolute_uri = uri
-        else:
-            absolute_uri = urljoin(base_url, uri)
-        proxy_uri = self._build_proxy_url_for_uri(absolute_uri)
-        return f"{prefix}{proxy_uri}{suffix}"
-
-    def _resolve_url(self, uri: str, base_url: str) -> str:
-        return urljoin(base_url, uri)
-
-    def _build_proxy_url_for_uri(self, absolute_uri: str) -> str:
-        encoded = quote(absolute_uri, safe="")
-        if absolute_uri.endswith(".m3u8"):
-            return f"/api/v1/youtube/proxy/manifest.m3u8?url={encoded}"
-        return f"/api/v1/youtube/proxy/segment.ts?url={encoded}"
-
-    async def proxy_segment(self, upstream_url: str) -> StreamingResponse:
-        async with httpx.AsyncClient(timeout=30.0) as client:
-            req = client.build_request("GET", upstream_url)
-            upstream = await client.send(req, stream=True)
-            return StreamingResponse(
-                upstream.aiter_bytes(),
-                status_code=upstream.status_code,
-                media_type="video/mp2t",
-                headers={"access-control-allow-origin": "*"},
-            )
diff --git a/backend/app/services/youtube_service.py b/backend/app/services/youtube_service.py
deleted file mode 100644
index 4b73c03..0000000
--- a/backend/app/services/youtube_service.py
+++ /dev/null
@@ -1,148 +0,0 @@
-import asyncio
-import logging
-import time
-from typing import Any
-from urllib.parse import quote
-
-import yt_dlp
-
-logger = logging.getLogger(__name__)
-
-
-def _is_po_token_error(msg: str) -> bool:
-    """Detect PO token expiration or bot detection errors from yt-dlp."""
-    indicators = [
-        "sign in to confirm",
-        "not a bot",
-        "bot detection",
-        "po token",
-        "potoken",
-    ]
-    msg_lower = msg.lower()
-    return any(indicator in msg_lower for indicator in indicators)
-
-
-class YouTubeService:
-    def __init__(self, timeout: int, cache_ttl: int):
-        self.timeout = timeout
-        self.cache_ttl = cache_ttl
-        self._cache: dict[str, tuple[float, dict]] = {}
-
-    async def extract_streams(self, url: str) -> dict:
-        now = time.monotonic()
-        if url in self._cache:
-            cached_at, cached_data = self._cache[url]
-            is_live = cached_data.get("is_live", False)
-            ttl = self.cache_ttl if is_live else self.cache_ttl * 6
-            if now - cached_at < ttl:
-                logger.debug("Cache hit for URL=%s age=%.1fs", url, now - cached_at)
-                return cached_data
-            logger.debug("Cache expired for URL=%s", url)
-
-        try:
-            loop = asyncio.get_running_loop()
-            info = await loop.run_in_executor(None, lambda: self._extract_sync(url))
-        except yt_dlp.utils.DownloadError as e:
-            error_msg = str(e)
-            logger.warning("yt-dlp extraction failed for URL=%s: %s", url, error_msg[:200])
-            if _is_po_token_error(error_msg):
-                logger.warning(
-                    "PO token expired or bot detected for URL=%s — invalidating cache, retry with fresh tokens recommended",
-                    url,
-                )
-                self._cache.pop(url, None)
-            return {"error": error_msg[:500], "video_id": "", "title": "", "formats": []}
-
-        live_status = info.get("live_status", "not_live")
-        is_live = live_status == "is_live"
-        is_upcoming = live_status == "is_upcoming"
-
-        result = {
-            "video_id": info.get("id", ""),
-            "title": info.get("title", ""),
-            "is_live": is_live,
-            "is_upcoming": is_upcoming,
-            "thumbnail_url": info.get("thumbnail"),
-            "formats": info.get("formats", []),
-            "error": None,
-        }
-
-        if not is_upcoming and info.get("formats"):
-            try:
-                video_fmt, audio_fmt = self._select_best_formats(info["formats"])
-                result["video_proxy_url"] = self._build_proxy_url(video_fmt["url"])
-                result["audio_proxy_url"] = self._build_proxy_url(audio_fmt["url"])
-            except ValueError as e:
-                result["error"] = str(e)
-
-        ttl = self.cache_ttl if is_live else self.cache_ttl * 6
-        self._cache[url] = (now, result)
-        return result
-
-    def _extract_sync(self, url: str) -> dict:
-        opts = self._get_ydl_opts(url)
-        with yt_dlp.YoutubeDL(opts) as ydl:
-            return ydl.extract_info(url, download=False)
-
-    def _get_ydl_opts(self, url: str) -> dict:
-        opts: dict[str, Any] = {
-            "quiet": True,
-            "no_warnings": True,
-            "extract_flat": False,
-        }
-        return opts
-
-    def _select_best_formats(self, formats: list[dict]) -> tuple[dict, dict]:
-        video_only = [
-            f
-            for f in formats
-            if f.get("vcodec", "none") != "none" and f.get("acodec", "none") == "none"
-        ]
-        audio_only = [
-            f
-            for f in formats
-            if f.get("acodec", "none") != "none" and f.get("vcodec", "none") == "none"
-        ]
-        combined = [
-            f
-            for f in formats
-            if f.get("vcodec", "none") != "none"
-            and f.get("acodec", "none") != "none"
-        ]
-
-        has_content = bool(combined or video_only or audio_only)
-        if not has_content:
-            raise ValueError("No streamable formats found")
-
-        if video_only and audio_only:
-            video_fmt = self._pick_best_video(video_only)
-            audio_fmt = max(audio_only, key=lambda f: f.get("abr") or 0)
-            return video_fmt, audio_fmt
-
-        if combined and audio_only:
-            combined_sorted = sorted(combined, key=lambda f: f.get("height") or 9999)
-            return combined_sorted[0], audio_only[0]
-
-        if combined:
-            best_combined = self._pick_best_video(combined)
-            return best_combined, best_combined
-
-        if video_only:
-            raise ValueError("No streamable audio format found")
-        raise ValueError("No streamable video format found")
-
-    def _pick_best_video(self, candidates: list[dict]) -> dict:
-        def _sort_key(f: dict) -> tuple[int, int, int, int]:
-            height = f.get("height") or 9999
-            tbr = f.get("tbr") or 0
-            is_m3u8 = 0 if f.get("protocol") in ("m3u8_native", "m3u8") else 1
-            at_or_under_480 = 0 if height <= 480 else 1
-            if at_or_under_480 == 0:
-                return (0, is_m3u8, -height, -tbr)
-            return (1, is_m3u8, height, -tbr)
-
-        return sorted(candidates, key=_sort_key)[0]
-
-    def _build_proxy_url(self, upstream_url: str) -> str:
-        encoded = quote(upstream_url, safe="")
-        return f"/api/v1/youtube/proxy/manifest.m3u8?url={encoded}"
diff --git a/backend/app/test/acceptance/test_acceptance_phase3_live.py b/backend/app/test/acceptance/test_acceptance_phase3_live.py
deleted file mode 100644
index 7f3dba1..0000000
--- a/backend/app/test/acceptance/test_acceptance_phase3_live.py
+++ /dev/null
@@ -1,97 +0,0 @@
-"""Acceptance test: Phase 3 YouTube live stream extraction and HLS proxy.
-
-Prerequisites:
-- BACKEND_URL env var set (default: http://localhost:8000)
-- YOUTUBE_TEST_LIVE_URL env var set (a real YouTube live stream URL, e.g., https://www.youtube.com/watch?v=fN9uYWCjQaw)
-- Backend server running with youtube_proxy_enabled=true
-- Network access to YouTube
-"""
-import os
-import time
-
-import pytest
-import requests
-
-
-@pytest.mark.acceptance
-@pytest.mark.slow
-class TestYouTubeLiveAcceptance:
-    """Real YouTube live stream extraction and HLS proxy verification."""
-
-    @pytest.fixture(autouse=True)
-    def check_prerequisites(self):
-        """Skip if prerequisites not met."""
-        backend_url = os.getenv("BACKEND_URL", "http://localhost:8000")
-        yt_url = os.getenv("YOUTUBE_TEST_LIVE_URL")
-        if not yt_url:
-            pytest.skip("YOUTUBE_TEST_LIVE_URL not set")
-        self.base_url = backend_url.rstrip("/")
-        self.yt_url = yt_url
-
-    def _extract_live(self):
-        """Helper: extract live stream, skip on error."""
-        resp = requests.post(
-            f"{self.base_url}/api/v1/youtube/extract",
-            json={"url": self.yt_url},
-            timeout=60,
-        )
-        assert resp.status_code == 200, f"Extract failed: {resp.text}"
-        data = resp.json()
-        if data.get("error"):
-            pytest.skip(f"Live stream error: {data['error']}")
-        return data
-
-    def test_extract_real_youtube_live(self):
-        """Extract a real YouTube live URL and verify live-specific properties."""
-        data = self._extract_live()
-
-        assert data["video_id"], "video_id should be non-empty"
-        assert data["title"], "title should be non-empty"
-        assert data["is_live"] is True, f"Expected is_live=True, got {data['is_live']}"
-        assert data["video_proxy_url"], "video_proxy_url should be present for live"
-        assert data["audio_proxy_url"], "audio_proxy_url should be present for live"
-        assert data["thumbnail_url"], "thumbnail_url should be present"
-        assert len(data["formats"]) > 0, "formats list should have entries (live uses combined formats)"
-
-        for fmt in data["formats"]:
-            assert "format_id" in fmt
-            assert "url" in fmt
-
-    def test_proxy_live_manifest(self):
-        """Extract live -> fetch manifest via proxy -> verify live HLS structure."""
-        data = self._extract_live()
-
-        proxy_url = data["video_proxy_url"]
-        if proxy_url.startswith("/"):
-            proxy_url = f"{self.base_url}{proxy_url}"
-
-        resp = requests.get(proxy_url, timeout=30)
-        assert resp.status_code == 200, f"Manifest proxy failed: {resp.status_code} {resp.text[:200]}"
-        assert (
-            "application/vnd.apple.mpegurl" in resp.headers.get("content-type", "")
-        ), f"Unexpected content-type: {resp.headers.get('content-type')}"
-        assert (
-            resp.headers.get("access-control-allow-origin") == "*"
-        ), "CORS header missing"
-
-        content = resp.text.strip()
-        assert content.startswith("#EXTM3U"), f"Manifest should start with #EXTM3U, got: {content[:100]}"
-        assert (
-            "#EXT-X-ENDLIST" not in content
-        ), "Live manifest should NOT contain #EXT-X-ENDLIST (stream is ongoing)"
-        assert (
-            "#EXT-X-TARGETDURATION" in content or "#EXT-X-STREAM-INF" in content
-        ), "Manifest should contain #EXT-X-TARGETDURATION or #EXT-X-STREAM-INF"
-
-    def test_live_cache_refresh(self):
-        """Live streams should have shorter cache TTL — verify re-extract works."""
-        data1 = self._extract_live()
-        video_id_1 = data1["video_id"]
-
-        time.sleep(1)
-
-        data2 = self._extract_live()
-        assert data2["video_id"] == video_id_1, "Re-extract should return same video_id"
-
-        assert data1["formats"] is not None
-        assert data2["formats"] is not None
diff --git a/backend/app/test/acceptance/test_acceptance_phase3_youtube.py b/backend/app/test/acceptance/test_acceptance_phase3_youtube.py
deleted file mode 100644
index b9a8686..0000000
--- a/backend/app/test/acceptance/test_acceptance_phase3_youtube.py
+++ /dev/null
@@ -1,148 +0,0 @@
-"""Acceptance test: Phase 3 YouTube VOD extraction and HLS proxy.
-
-Prerequisites:
-- BACKEND_URL env var set (default: http://localhost:8000)
-- YOUTUBE_TEST_VOD_URL env var set (a real YouTube VOD URL, e.g., https://www.youtube.com/watch?v=5bF3tkO5jAA)
-- Backend server running with youtube_proxy_enabled=true
-- Network access to YouTube
-"""
-import json
-import os
-import time
-
-import pytest
-import requests
-
-
-@pytest.mark.acceptance
-@pytest.mark.slow
-class TestYouTubeVODAcceptance:
-    """Real YouTube VOD extraction and HLS proxy verification."""
-
-    @pytest.fixture(autouse=True)
-    def check_prerequisites(self):
-        """Skip if prerequisites not met."""
-        backend_url = os.getenv("BACKEND_URL", "http://localhost:8000")
-        yt_url = os.getenv("YOUTUBE_TEST_VOD_URL")
-        if not yt_url:
-            pytest.skip("YOUTUBE_TEST_VOD_URL not set")
-        self.base_url = backend_url.rstrip("/")
-        self.yt_url = yt_url
-
-    def test_extract_real_youtube_vod(self):
-        """Extract a real YouTube VOD URL and verify response structure."""
-        resp = requests.post(
-            f"{self.base_url}/api/v1/youtube/extract",
-            json={"url": self.yt_url},
-            timeout=60,
-        )
-        assert resp.status_code == 200, f"Extract failed: {resp.text}"
-        data = resp.json()
-
-        assert data["error"] is None, f"Extraction returned error: {data['error']}"
-        assert data["video_id"], "video_id should be non-empty"
-        assert data["title"], "title should be non-empty"
-        assert data["is_live"] is False, "VOD should not be live"
-        assert data["is_upcoming"] is False, "VOD should not be upcoming"
-        assert data["video_proxy_url"], "video_proxy_url should be present"
-        assert data["audio_proxy_url"], "audio_proxy_url should be present"
-        assert data["thumbnail_url"], "thumbnail_url should be present"
-        assert len(data["formats"]) > 0, "formats list should be non-empty"
-
-        for fmt in data["formats"]:
-            assert "format_id" in fmt
-            assert "url" in fmt
-
-    def test_proxy_manifest_from_real_vod(self):
-        """Extract -> fetch manifest via proxy -> verify valid M3U8."""
-        resp = requests.post(
-            f"{self.base_url}/api/v1/youtube/extract",
-            json={"url": self.yt_url},
-            timeout=60,
-        )
-        assert resp.status_code == 200, f"Extract failed: {resp.text}"
-        data = resp.json()
-        assert data["video_proxy_url"], "No video_proxy_url in extract response"
-
-        proxy_url = data["video_proxy_url"]
-        if proxy_url.startswith("/"):
-            proxy_url = f"{self.base_url}{proxy_url}"
-
-        resp = requests.get(proxy_url, timeout=30)
-        assert resp.status_code == 200, f"Manifest proxy failed: {resp.status_code} {resp.text[:200]}"
-        assert (
-            "application/vnd.apple.mpegurl" in resp.headers.get("content-type", "")
-        ), f"Unexpected content-type: {resp.headers.get('content-type')}"
-        assert (
-            resp.headers.get("access-control-allow-origin") == "*"
-        ), "CORS header missing"
-
-        body = resp.text.strip()
-        assert body.startswith("#EXTM3U"), f"Manifest should start with #EXTM3U, got: {body[:100]}"
-        assert (
-            "#EXT-X-STREAM-INF" in body or "#EXTINF" in body
-        ), "Manifest should contain #EXT-X-STREAM-INF or #EXTINF"
-
-    def test_proxy_segment_from_real_vod(self):
-        """Proxy a TS segment and verify it returns video data."""
-        resp = requests.post(
-            f"{self.base_url}/api/v1/youtube/extract",
-            json={"url": self.yt_url},
-            timeout=60,
-        )
-        assert resp.status_code == 200, f"Extract failed: {resp.text}"
-        data = resp.json()
-        assert data["video_proxy_url"], "No video_proxy_url in extract response"
-
-        proxy_url = data["video_proxy_url"]
-        if proxy_url.startswith("/"):
-            proxy_url = f"{self.base_url}{proxy_url}"
-
-        resp = requests.get(proxy_url, timeout=30)
-        assert resp.status_code == 200, f"Master manifest failed: {resp.status_code}"
-        master_body = resp.text.strip()
-
-        variant_url = None
-        lines = master_body.split("\n")
-        for line in lines:
-            stripped = line.strip()
-            if stripped.startswith("/api/v1/youtube/proxy/manifest.m3u8?url="):
-                variant_url = stripped
-                break
-
-        if variant_url is None:
-            pytest.skip("No variant manifest URL found (may be a non-master manifest)")
-
-        if variant_url.startswith("/"):
-            variant_url = f"{self.base_url}{variant_url}"
-
-        resp = requests.get(variant_url, timeout=30)
-        assert resp.status_code == 200, f"Variant manifest failed: {resp.status_code}"
-        variant_body = resp.text.strip()
-        assert variant_body.startswith("#EXTM3U"), "Variant should start with #EXTM3U"
-
-        segment_url = None
-        for line in variant_body.split("\n"):
-            stripped = line.strip()
-            if stripped.startswith("/api/v1/youtube/proxy/segment.ts?url="):
-                segment_url = stripped
-                break
-
-        assert segment_url is not None, "No segment URL found in variant manifest"
-
-        if segment_url.startswith("/"):
-            segment_url = f"{self.base_url}{segment_url}"
-
-        seg_resp = requests.get(segment_url, timeout=30)
-        if seg_resp.status_code != 200:
-            pytest.skip(
-                f"Segment proxy returned {seg_resp.status_code} (YouTube segment may have expired)"
-            )
-
-        assert (
-            seg_resp.headers.get("access-control-allow-origin") == "*"
-        ), "CORS header missing on segment"
-        assert len(seg_resp.content) > 0, "Segment body should be non-empty"
-        assert (
-            seg_resp.content[0] == 0x47
-        ), "MPEG-TS segment should start with 0x47 sync byte"
diff --git a/backend/app/test/test_integration_phase3.py b/backend/app/test/test_integration_phase3.py
deleted file mode 100644
index eaefb94..0000000
--- a/backend/app/test/test_integration_phase3.py
+++ /dev/null
@@ -1,361 +0,0 @@
-"""Integration test: Phase 3 end-to-end YouTube extract → HLS proxy.
-
-Covers:
-- Full extract → proxy flow with mocked yt-dlp and upstream HTTP
-- Proxy manifest rewriting through real HLSProxyService
-- Proxy segment passthrough through real HLSProxyService
-- Error handling: upstream failure after extract
-- Config: youtube_proxy_enabled flag
-
-All yt-dlp calls and upstream HTTP servers are mocked.
-Real FastAPI TestClient with real YouTube router and HLSProxyService.
-"""
-from unittest.mock import AsyncMock, MagicMock, patch
-from urllib.parse import quote
-
-import pytest
-from fastapi import FastAPI
-from fastapi.testclient import TestClient
-
-
-# ---------------------------------------------------------------------------
-# Helpers — fake yt-dlp format data
-# ---------------------------------------------------------------------------
-
-def _make_format(
-    format_id: str,
-    height: int | None = None,
-    vcodec: str = "none",
-    acodec: str = "none",
-    ext: str = "mp4",
-    protocol: str = "https",
-    url: str = "",
-    abr: float | None = None,
-    tbr: float | None = None,
-    resolution: str | None = None,
-) -> dict:
-    return {
-        "format_id": format_id,
-        "height": height,
-        "width": height * 16 // 9 if height else None,
-        "vcodec": vcodec,
-        "acodec": acodec,
-        "ext": ext,
-        "protocol": protocol,
-        "url": url or f"https://example.com/{format_id}.{ext}",
-        "abr": abr,
-        "tbr": tbr,
-        "resolution": resolution or (f"{height * 16 // 9}x{height}" if height else None),
-    }
-
-
-def _vod_info(video_id: str = "abc123") -> dict:
-    return {
-        "id": video_id,
-        "title": "Test VOD Video",
-        "thumbnail": f"https://i.ytimg.com/vi/{video_id}/hqdefault.jpg",
-        "live_status": "not_live",
-        "duration": 300,
-        "formats": [
-            _make_format("137", height=1080, vcodec="avc1.640028", acodec="none", tbr=5000),
-            _make_format("136", height=720, vcodec="avc1.640028", acodec="none", tbr=2500),
-            _make_format("135", height=480, vcodec="avc1.640028", acodec="none", tbr=1200),
-            _make_format("134", height=360, vcodec="avc1.640028", acodec="none", tbr=600),
-            _make_format("133", height=240, vcodec="avc1.640028", acodec="none", tbr=300),
-            _make_format("140", acodec="mp4a.40.2", vcodec="none", abr=128),
-            _make_format("251", acodec="opus", vcodec="none", abr=160),
-            _make_format("18", height=360, vcodec="avc1.42001E", acodec="mp4a.40.2", tbr=500),
-        ],
-    }
-
-
-def _vod_info_hls(video_id: str = "abc123") -> dict:
-    return {
-        "id": video_id,
-        "title": "Test VOD with HLS",
-        "thumbnail": f"https://i.ytimg.com/vi/{video_id}/hqdefault.jpg",
-        "live_status": "not_live",
-        "duration": 600,
-        "formats": [
-            _make_format("136", height=720, vcodec="avc1.640028", acodec="none", ext="m3u8", protocol="m3u8_native", tbr=2500),
-            _make_format("135", height=480, vcodec="avc1.640028", acodec="none", ext="m3u8", protocol="m3u8_native", tbr=1200),
-            _make_format("140", acodec="mp4a.40.2", vcodec="none", ext="m3u8", protocol="m3u8_native", abr=128),
-        ],
-    }
-
-
-def _live_info(video_id: str = "live999") -> dict:
-    return {
-        "id": video_id,
-        "title": "Live Stream Test",
-        "thumbnail": f"https://i.ytimg.com/vi/{video_id}/hqdefault_live.jpg",
-        "live_status": "is_live",
-        "duration": None,
-        "formats": [
-            _make_format("91", height=144, vcodec="avc1.42C00B", acodec="mp4a.40.5", ext="mp4", protocol="m3u8_native"),
-            _make_format("92", height=240, vcodec="avc1.4D4015", acodec="mp4a.40.5", ext="mp4", protocol="m3u8_native"),
-            _make_format("93", height=360, vcodec="avc1.4D401E", acodec="mp4a.40.2", ext="mp4", protocol="m3u8_native"),
-            _make_format("94", height=480, vcodec="avc1.4D401F", acodec="mp4a.40.2", ext="mp4", protocol="m3u8_native", tbr=1200),
-            _make_format("95", height=720, vcodec="avc1.4D401F", acodec="mp4a.40.2", ext="mp4", protocol="m3u8_native"),
-        ],
-    }
-
-
-def _make_mock_ydl(return_value: dict | Exception) -> MagicMock:
-    mock_instance = MagicMock()
-    if isinstance(return_value, Exception):
-        mock_instance.extract_info.side_effect = return_value
-    else:
-        mock_instance.extract_info.return_value = return_value
-    mock_ydl = MagicMock()
-    mock_ydl.__enter__.return_value = mock_instance
-    mock_ydl.__exit__.return_value = None
-    return mock_ydl
-
-
-# ---------------------------------------------------------------------------
-# Helpers — mock httpx responses
-# ---------------------------------------------------------------------------
-
-def _make_mock_stream_response(status_code: int = 200, **kwargs) -> MagicMock:
-    mock = MagicMock()
-    mock.status_code = status_code
-    mock.aclose = AsyncMock()
-    mock.__aenter__ = AsyncMock(return_value=mock)
-    mock.__aexit__ = AsyncMock(return_value=None)
-    for key, value in kwargs.items():
-        setattr(mock, key, value)
-    return mock
-
-
-def _make_mock_client(resp_mock: MagicMock) -> MagicMock:
-    client = MagicMock()
-    client.stream = MagicMock(return_value=resp_mock)
-    client.send = AsyncMock(return_value=resp_mock)
-    client.build_request = MagicMock(return_value=MagicMock())
-    client.aclose = AsyncMock()
-    client.__aenter__ = AsyncMock(return_value=client)
-    client.__aexit__ = AsyncMock(return_value=None)
-    return client
-
-
-async def _async_iter_lines(text: str):
-    for line in text.split("\n"):
-        yield line
-
-
-async def _async_iter_bytes(chunks: list[bytes]):
-    for chunk in chunks:
-        yield chunk
-
-
-# ---------------------------------------------------------------------------
-# Shared fixture builder
-# ---------------------------------------------------------------------------
-
-def _build_client(monkeypatch, enabled: bool = True):
-    from app.routers.youtube import router, _get_youtube_service
-    from app.core.config import get_settings
-
-    _get_youtube_service.cache_clear()
-    get_settings.cache_clear()
-    monkeypatch.setenv("YOUTUBE_PROXY_ENABLED", "true" if enabled else "false")
-    monkeypatch.setenv("YT_DLP_TIMEOUT", "30")
-    get_settings.cache_clear()
-
-    app = FastAPI()
-    app.include_router(router, prefix="/api/v1")
-    return TestClient(app)
-
-
-# ---------------------------------------------------------------------------
-# Integration: Full extract → proxy flow
-# ---------------------------------------------------------------------------
-
-class TestExtractAndProxyFlow:
-    """Full extract → proxy flow with mocked yt-dlp and upstream."""
-
-    @pytest.fixture
-    def client(self, monkeypatch):
-        return _build_client(monkeypatch, enabled=True)
-
-    def test_extract_vod_then_proxy_manifest(self, client):
-        mock_ydl = _make_mock_ydl(_vod_info_hls("vod1"))
-
-        with patch("app.services.youtube_service.yt_dlp.YoutubeDL", return_value=mock_ydl):
-            extract_resp = client.post(
-                "/api/v1/youtube/extract",
-                json={"url": "https://www.youtube.com/watch?v=vod1"},
-            )
-
-        assert extract_resp.status_code == 200
-        data = extract_resp.json()
-        proxy_url = data["video_proxy_url"]
-        assert proxy_url is not None
-        assert "manifest.m3u8?url=" in proxy_url
-
-        upstream_manifest = (
-            "#EXTM3U\n"
-            "#EXT-X-VERSION:3\n"
-            "#EXTINF:6.0,\n"
-            "segment_0.ts\n"
-            "#EXT-X-ENDLIST\n"
-        )
-        upstream = _make_mock_stream_response(
-            status_code=200,
-            aiter_lines=lambda: _async_iter_lines(upstream_manifest),
-        )
-
-        with patch("app.routers.youtube.httpx.AsyncClient") as mock_cls:
-            mock_client = _make_mock_client(upstream)
-            mock_cls.return_value = mock_client
-
-            proxy_resp = client.get(proxy_url)
-
-        assert proxy_resp.status_code == 200
-        assert proxy_resp.headers.get("access-control-allow-origin") == "*"
-        content = proxy_resp.text
-        assert "#EXTM3U" in content
-        assert "/api/v1/youtube/proxy/segment.ts?url=" in content
-        assert "#EXT-X-ENDLIST" in content
-
-    def test_extract_vod_then_proxy_segment(self, client):
-        mock_ydl = _make_mock_ydl(_vod_info_hls("vod2"))
-
-        with patch("app.services.youtube_service.yt_dlp.YoutubeDL", return_value=mock_ydl):
-            extract_resp = client.post(
-                "/api/v1/youtube/extract",
-                json={"url": "https://www.youtube.com/watch?v=vod2"},
-            )
-
-        assert extract_resp.status_code == 200
-
-        segment_upstream_url = "https://example.com/segment_0.ts"
-        segment_proxy_url = (
-            f"/api/v1/youtube/proxy/segment.ts?url={quote(segment_upstream_url, safe='')}"
-        )
-
-        resp_mock = _make_mock_stream_response(
-            status_code=200,
-            headers={"content-type": "video/mp2t"},
-            aiter_bytes=lambda: _async_iter_bytes([b"\x47" * 188]),
-        )
-        client_mock = _make_mock_client(resp_mock)
-
-        with patch("app.services.hls_proxy.httpx.AsyncClient", return_value=client_mock):
-            seg_resp = client.get(segment_proxy_url)
-
-        assert seg_resp.status_code == 200
-        assert seg_resp.headers.get("access-control-allow-origin") == "*"
-        assert seg_resp.headers.get("content-type") == "video/mp2t"
-
-    def test_extract_live_then_proxy_manifest(self, client):
-        mock_ydl = _make_mock_ydl(_live_info("live1"))
-
-        with patch("app.services.youtube_service.yt_dlp.YoutubeDL", return_value=mock_ydl):
-            extract_resp = client.post(
-                "/api/v1/youtube/extract",
-                json={"url": "https://www.youtube.com/watch?v=live1"},
-            )
-
-        assert extract_resp.status_code == 200
-        data = extract_resp.json()
-        assert data["is_live"] is True
-        proxy_url = data["video_proxy_url"]
-        assert proxy_url is not None
-
-        live_manifest = (
-            "#EXTM3U\n"
-            "#EXT-X-VERSION:3\n"
-            "#EXT-X-TARGETDURATION:4\n"
-            "#EXTINF:4.0,\n"
-            "segment_live_0.ts\n"
-            "#EXTINF:4.0,\n"
-            "segment_live_1.ts\n"
-        )
-        upstream = _make_mock_stream_response(
-            status_code=200,
-            aiter_lines=lambda: _async_iter_lines(live_manifest),
-        )
-
-        with patch("app.routers.youtube.httpx.AsyncClient") as mock_cls:
-            mock_client = _make_mock_client(upstream)
-            mock_cls.return_value = mock_client
-
-            proxy_resp = client.get(proxy_url)
-
-        assert proxy_resp.status_code == 200
-        content = proxy_resp.text
-        assert "#EXTM3U" in content
-        assert "#EXT-X-ENDLIST" not in content
-        assert "/api/v1/youtube/proxy/segment.ts?url=" in content
-
-    def test_extract_cache_hit_bypasses_ytdlp(self, client):
-        mock_ydl = _make_mock_ydl(_vod_info("cached_vod"))
-        instance = mock_ydl.__enter__.return_value
-
-        with patch("app.services.youtube_service.yt_dlp.YoutubeDL", return_value=mock_ydl):
-            r1 = client.post(
-                "/api/v1/youtube/extract",
-                json={"url": "https://www.youtube.com/watch?v=cached_vod"},
-            )
-            r2 = client.post(
-                "/api/v1/youtube/extract",
-                json={"url": "https://www.youtube.com/watch?v=cached_vod"},
-            )
-
-        assert r1.status_code == 200
-        assert r2.status_code == 200
-        assert r1.json()["video_id"] == r2.json()["video_id"]
-        assert instance.extract_info.call_count == 1
-
-
-# ---------------------------------------------------------------------------
-# Integration: Upstream failures after successful extraction
-# ---------------------------------------------------------------------------
-
-class TestProxyAfterExtract:
-    """Error scenarios where upstream fails after successful extraction."""
-
-    @pytest.fixture
-    def client(self, monkeypatch):
-        return _build_client(monkeypatch, enabled=True)
-
-    def test_upstream_manifest_unavailable_after_extract(self, client):
-        mock_ydl = _make_mock_ydl(_vod_info_hls("err1"))
-
-        with patch("app.services.youtube_service.yt_dlp.YoutubeDL", return_value=mock_ydl):
-            extract_resp = client.post(
-                "/api/v1/youtube/extract",
-                json={"url": "https://www.youtube.com/watch?v=err1"},
-            )
-
-        assert extract_resp.status_code == 200
-        proxy_url = extract_resp.json()["video_proxy_url"]
-
-        upstream = _make_mock_stream_response(status_code=404)
-
-        with patch("app.routers.youtube.httpx.AsyncClient") as mock_cls:
-            mock_client = _make_mock_client(upstream)
-            mock_cls.return_value = mock_client
-
-            proxy_resp = client.get(proxy_url)
-
-        assert proxy_resp.status_code == 502
-
-
-# ---------------------------------------------------------------------------
-# Config: youtube_proxy_enabled flag
-# ---------------------------------------------------------------------------
-
-class TestExtractDisabled:
-    """Config flag youtube_proxy_enabled=False."""
-
-    def test_extract_returns_503_when_disabled(self, monkeypatch):
-        client = _build_client(monkeypatch, enabled=False)
-
-        resp = client.post(
-            "/api/v1/youtube/extract",
-            json={"url": "https://www.youtube.com/watch?v=abc123"},
-        )
-        assert resp.status_code == 503
diff --git a/backend/app/test/test_phase3_config.py b/backend/app/test/test_phase3_config.py
deleted file mode 100644
index 9922e20..0000000
--- a/backend/app/test/test_phase3_config.py
+++ /dev/null
@@ -1,177 +0,0 @@
-"""Phase 3.1 tests: Configuration and infrastructure setup for YouTube proxy.
-
-Covers:
-- Config fields: youtube_proxy_enabled, yt_dlp_timeout, yt_dlp_cache_ttl defaults and env loading
-- Model schemas: YouTubeExtractRequest, YouTubeStreamResponse, StreamFormat
-- Service stubs: YouTubeService, HLSProxyService instantiation
-- Router registration: youtube.router mounted, endpoint responds 200 with mock
-"""
-from unittest.mock import MagicMock, patch
-
-import pytest
-from fastapi import FastAPI
-from fastapi.testclient import TestClient
-
-
-class TestYouTubeProxyConfig:
-    """Config fields for YouTube proxy exist with correct defaults."""
-
-    @pytest.fixture(autouse=True)
-    def clear_cache(self):
-        from app.core.config import get_settings
-
-        get_settings.cache_clear()
-        yield
-        get_settings.cache_clear()
-
-    def test_defaults(self):
-        from app.core.config import get_settings
-
-        s = get_settings()
-        assert s.youtube_proxy_enabled is True
-        assert s.yt_dlp_timeout == 30
-        assert s.yt_dlp_cache_ttl == 300
-
-    def test_env_override(self, monkeypatch):
-        monkeypatch.setenv("YOUTUBE_PROXY_ENABLED", "false")
-        monkeypatch.setenv("YT_DLP_TIMEOUT", "60")
-        monkeypatch.setenv("YT_DLP_CACHE_TTL", "600")
-
-        from app.core.config import get_settings
-
-        s = get_settings()
-        assert s.youtube_proxy_enabled is False
-        assert s.yt_dlp_timeout == 60
-        assert s.yt_dlp_cache_ttl == 600
-
-    def test_bool_parsing(self, monkeypatch):
-        """Bool fields accept 'true'/'false', '1'/'0' (pydantic-settings)."""
-        monkeypatch.setenv("YOUTUBE_PROXY_ENABLED", "0")
-
-        from app.core.config import get_settings
-
-        s = get_settings()
-        assert s.youtube_proxy_enabled is False
-
-
-class TestYouTubeModels:
-    """Pydantic models for YouTube stream extraction."""
-
-    def test_extract_request(self):
-        from app.models.youtube import YouTubeExtractRequest
-
-        req = YouTubeExtractRequest(url="https://www.youtube.com/watch?v=abc123")
-        assert req.url == "https://www.youtube.com/watch?v=abc123"
-
-    def test_stream_response_defaults(self):
-        from app.models.youtube import YouTubeStreamResponse
-
-        resp = YouTubeStreamResponse(video_id="abc123", title="Test Video")
-        assert resp.video_id == "abc123"
-        assert resp.title == "Test Video"
-        assert resp.is_live is False
-        assert resp.is_upcoming is False
-        assert resp.video_proxy_url is None
-        assert resp.audio_proxy_url is None
-        assert resp.formats == []
-        assert resp.error is None
-
-    def test_stream_format(self):
-        from app.models.youtube import StreamFormat
-
-        fmt = StreamFormat(
-            format_id="140",
-            url="https://example.com/audio.m3u8",
-            is_audio_only=True,
-            codec="mp4a.40.2",
-        )
-        assert fmt.format_id == "140"
-        assert fmt.is_audio_only is True
-        assert fmt.is_video_only is False
-        assert fmt.resolution is None
-
-
-class TestYouTubeServices:
-    """Service stubs can be imported and instantiated."""
-
-    def test_youtube_service_instantiate(self):
-        from app.services.youtube_service import YouTubeService
-
-        svc = YouTubeService(timeout=30, cache_ttl=300)
-        assert svc.timeout == 30
-        assert svc.cache_ttl == 300
-
-    def test_youtube_service_extract_is_async(self):
-        from app.services.youtube_service import YouTubeService
-
-        svc = YouTubeService(timeout=30, cache_ttl=300)
-        import inspect
-
-        assert inspect.iscoroutinefunction(svc.extract_streams)
-
-    def test_hls_proxy_instantiate(self):
-        from app.services.hls_proxy import HLSProxyService
-
-        svc = HLSProxyService()
-        assert svc is not None
-
-
-class TestYouTubeRouter:
-    """YouTube router is mounted and stub endpoint responds correctly."""
-
-    @pytest.fixture
-    def youtube_client(self):
-        from app.routers.youtube import router
-        from app.core.config import get_settings
-
-        get_settings.cache_clear()
-        app = FastAPI()
-        app.include_router(router, prefix="/api/v1")
-        return TestClient(app)
-
-    def test_extract_responds_with_mocked_ytdlp(self, youtube_client):
-        from app.routers.youtube import _get_youtube_service
-
-        _get_youtube_service.cache_clear()
-
-        vod_info = {
-            "id": "test123",
-            "title": "Test",
-            "thumbnail": "https://example.com/thumb.jpg",
-            "live_status": "not_live",
-            "formats": [
-                {
-                    "format_id": "135", "height": 480,
-                    "vcodec": "avc1", "acodec": "none",
-                    "ext": "mp4", "protocol": "https",
-                    "url": "https://example.com/video.mp4", "tbr": 1200,
-                },
-                {
-                    "format_id": "140",
-                    "vcodec": "none", "acodec": "mp4a",
-                    "ext": "m4a", "protocol": "https",
-                    "url": "https://example.com/audio.m4a", "abr": 128,
-                },
-            ],
-        }
-        mock_ydl = MagicMock()
-        mock_instance = MagicMock()
-        mock_instance.extract_info.return_value = vod_info
-        mock_ydl.__enter__.return_value = mock_instance
-
-        with patch("app.services.youtube_service.yt_dlp.YoutubeDL", return_value=mock_ydl):
-            resp = youtube_client.post(
-                "/api/v1/youtube/extract",
-                json={"url": "https://www.youtube.com/watch?v=test123"},
-            )
-
-        assert resp.status_code == 200
-        data = resp.json()
-        assert data["video_id"] == "test123"
-        assert data["video_proxy_url"] is not None
-        assert data["audio_proxy_url"] is not None
-
-    def test_router_tag(self):
-        from app.routers.youtube import router
-
-        assert any(tag == "youtube" for tag in router.tags)
diff --git a/backend/app/test/test_phase3_hls_proxy.py b/backend/app/test/test_phase3_hls_proxy.py
deleted file mode 100644
index 806b84f..0000000
--- a/backend/app/test/test_phase3_hls_proxy.py
+++ /dev/null
@@ -1,337 +0,0 @@
-"""Phase 3.3 tests: HLS proxy service — manifest rewriting and segment proxying.
-
-Covers:
-- Manifest line rewriting: segments, sub-manifests, EXT-X-KEY URIs, pass-through tags
-- URL resolution: relative paths, absolute paths, absolute URLs
-- Segment proxying: StreamingResponse with correct Content-Type and CORS headers
-- Route integration: GET /youtube/proxy/manifest.m3u8 and /segment.ts
-- Error handling: upstream failures → 502, client disconnect
-- CORS headers on every response
-"""
-from unittest.mock import AsyncMock, MagicMock, patch
-
-import pytest
-from httpx import Response, Request
-
-
-def _make_mock_stream_response(status_code: int = 200, **kwargs) -> MagicMock:
-    mock = MagicMock()
-    mock.status_code = status_code
-    mock.aclose = AsyncMock()
-    mock.__aenter__ = AsyncMock(return_value=mock)
-    mock.__aexit__ = AsyncMock(return_value=None)
-    for key, value in kwargs.items():
-        setattr(mock, key, value)
-    return mock
-
-
-def _make_mock_client(resp_mock: MagicMock) -> MagicMock:
-    client = MagicMock()
-    client.stream = MagicMock(return_value=resp_mock)
-    client.send = AsyncMock(return_value=resp_mock)
-    client.build_request = MagicMock(return_value=MagicMock())
-    client.aclose = AsyncMock()
-    client.__aenter__ = AsyncMock(return_value=client)
-    client.__aexit__ = AsyncMock(return_value=None)
-    return client
-
-
-# ---------------------------------------------------------------------------
-# Unit: Line rewriting
-# ---------------------------------------------------------------------------
-
-class TestLineRewriting:
-    @pytest.fixture
-    def svc(self):
-        from app.services.hls_proxy import HLSProxyService
-
-        return HLSProxyService()
-
-    def test_passes_through_comment_tags(self, svc):
-        base = "https://example.com/manifest.m3u8"
-        assert svc._rewrite_line("#EXTM3U", base) == "#EXTM3U"
-        assert svc._rewrite_line("#EXT-X-VERSION:3", base) == "#EXT-X-VERSION:3"
-        assert svc._rewrite_line("#EXT-X-TARGETDURATION:6", base) == "#EXT-X-TARGETDURATION:6"
-        assert svc._rewrite_line("#EXT-X-MEDIA-SEQUENCE:0", base) == "#EXT-X-MEDIA-SEQUENCE:0"
-        assert svc._rewrite_line("#EXT-X-ENDLIST", base) == "#EXT-X-ENDLIST"
-        assert svc._rewrite_line("# This is a comment", base) == "# This is a comment"
-        assert svc._rewrite_line("#EXT-X-STREAM-INF:BANDWIDTH=800000,RESOLUTION=640x360", base) == "#EXT-X-STREAM-INF:BANDWIDTH=800000,RESOLUTION=640x360"
-
-    def test_passes_through_empty_lines(self, svc):
-        assert svc._rewrite_line("", "https://example.com/base.m3u8") == ""
-
-    def test_rewrites_ts_segment(self, svc):
-        base = "https://example.com/path/manifest.m3u8"
-        result = svc._rewrite_line("segment_0.ts", base)
-        assert result.startswith("/api/v1/youtube/proxy/segment.ts?url=")
-
-    def test_rewrites_m3u8_submanifest(self, svc):
-        base = "https://example.com/path/manifest.m3u8"
-        result = svc._rewrite_line("variant_360p.m3u8", base)
-        assert result.startswith("/api/v1/youtube/proxy/manifest.m3u8?url=")
-
-    def test_rewrites_ext_x_key_uri(self, svc):
-        base = "https://example.com/manifest.m3u8"
-        result = svc._rewrite_line('#EXT-X-KEY:METHOD=AES-128,URI="key.bin",IV=0x1234', base)
-        assert result.startswith("#EXT-X-KEY:METHOD=AES-128,URI=\"")
-        assert "/api/v1/youtube/proxy/segment.ts?url=" in result
-
-    def test_rewrites_m3u8_key_uri(self, svc):
-        base = "https://example.com/manifest.m3u8"
-        result = svc._rewrite_line('#EXT-X-KEY:METHOD=AES-128,URI="keys/variant.m3u8"', base)
-        assert result.startswith("#EXT-X-KEY:METHOD=AES-128,URI=\"")
-        assert "/api/v1/youtube/proxy/manifest.m3u8?url=" in result
-
-    def test_rewrites_absolute_url_segment(self, svc):
-        base = "https://example.com/manifest.m3u8"
-        result = svc._rewrite_line("https://cdn.example.com/segments/0.ts", base)
-        assert result.startswith("/api/v1/youtube/proxy/segment.ts?url=")
-
-    def test_passes_through_inf_tag_with_commas(self, svc):
-        base = "https://example.com/manifest.m3u8"
-        result = svc._rewrite_line("#EXTINF:6.000,Some description, with commas", base)
-        assert result == "#EXTINF:6.000,Some description, with commas"
-
-
-# ---------------------------------------------------------------------------
-# Unit: URL resolution
-# ---------------------------------------------------------------------------
-
-class TestURLResolution:
-    @pytest.fixture
-    def svc(self):
-        from app.services.hls_proxy import HLSProxyService
-
-        return HLSProxyService()
-
-    def test_relative_path_resolved(self, svc):
-        result = svc._resolve_url("segment_0.ts", "https://example.com/path/manifest.m3u8")
-        assert result == "https://example.com/path/segment_0.ts"
-
-    def test_absolute_path_resolved(self, svc):
-        result = svc._resolve_url("/segments/0.ts", "https://example.com/path/manifest.m3u8")
-        assert result == "https://example.com/segments/0.ts"
-
-    def test_absolute_url_passthrough(self, svc):
-        result = svc._resolve_url("https://cdn.example.com/0.ts", "https://example.com/manifest.m3u8")
-        assert result == "https://cdn.example.com/0.ts"
-
-    def test_parent_dir_resolved(self, svc):
-        result = svc._resolve_url("../segments/0.ts", "https://example.com/path/to/manifest.m3u8")
-        assert result == "https://example.com/path/segments/0.ts"
-
-
-# ---------------------------------------------------------------------------
-# Unit: Proxy URL construction
-# ---------------------------------------------------------------------------
-
-class TestProxyURLConstruction:
-    @pytest.fixture
-    def svc(self):
-        from app.services.hls_proxy import HLSProxyService
-
-        return HLSProxyService()
-
-    def test_segment_extension_uses_segment_proxy(self, svc):
-        from urllib.parse import unquote
-
-        upstream = "https://cdn.example.com/segments/0.ts"
-        proxy = svc._build_proxy_url_for_uri(upstream)
-        assert proxy.startswith("/api/v1/youtube/proxy/segment.ts?url=")
-        encoded = proxy.split("url=", 1)[1]
-        assert unquote(encoded) == upstream
-
-    def test_m3u8_extension_uses_manifest_proxy(self, svc):
-        from urllib.parse import unquote
-
-        upstream = "https://cdn.example.com/variants/360p.m3u8"
-        proxy = svc._build_proxy_url_for_uri(upstream)
-        assert proxy.startswith("/api/v1/youtube/proxy/manifest.m3u8?url=")
-        encoded = proxy.split("url=", 1)[1]
-        assert unquote(encoded) == upstream
-
-    def test_unknown_extension_uses_segment_proxy(self, svc):
-        from urllib.parse import unquote
-
-        upstream = "https://cdn.example.com/init.mp4"
-        proxy = svc._build_proxy_url_for_uri(upstream)
-        assert proxy.startswith("/api/v1/youtube/proxy/segment.ts?url=")
-
-
-# ---------------------------------------------------------------------------
-# Integration: Manifest rewriting with mocked httpx
-# ---------------------------------------------------------------------------
-
-SAMPLE_MANIFEST = """#EXTM3U
-#EXT-X-VERSION:3
-#EXT-X-TARGETDURATION:6
-#EXT-X-MEDIA-SEQUENCE:0
-#EXTINF:6.000,
-segment_0.ts
-#EXTINF:6.000,
-segment_1.ts
-#EXT-X-ENDLIST
-"""
-
-
-class TestManifestRewriting:
-    @pytest.fixture
-    def svc(self):
-        from app.services.hls_proxy import HLSProxyService
-
-        return HLSProxyService()
-
-    @pytest.mark.asyncio
-    async def test_full_manifest_rewritten(self, svc):
-        upstream = _make_mock_stream_response(
-            status_code=200,
-            aiter_lines=lambda: _async_iter_lines(SAMPLE_MANIFEST),
-        )
-        lines = []
-        async for line in svc.rewrite_manifest("https://example.com/video.m3u8", upstream):
-            lines.append(line)
-
-        assert lines[0] == "#EXTM3U\n"
-        assert lines[1] == "#EXT-X-VERSION:3\n"
-        assert lines[2] == "#EXT-X-TARGETDURATION:6\n"
-        assert lines[3] == "#EXT-X-MEDIA-SEQUENCE:0\n"
-        assert lines[4] == "#EXTINF:6.000,\n"
-        assert "/api/v1/youtube/proxy/segment.ts?url=" in lines[5]
-        assert lines[6] == "#EXTINF:6.000,\n"
-        assert "/api/v1/youtube/proxy/segment.ts?url=" in lines[7]
-        assert lines[8] == "#EXT-X-ENDLIST\n"
-
-    @pytest.mark.asyncio
-    async def test_master_manifest_with_variants(self, svc):
-        master = """#EXTM3U
-#EXT-X-STREAM-INF:BANDWIDTH=800000,RESOLUTION=640x360
-variant_360p.m3u8
-#EXT-X-STREAM-INF:BANDWIDTH=1400000,RESOLUTION=842x480
-variant_480p.m3u8
-"""
-        upstream = _make_mock_stream_response(
-            status_code=200,
-            aiter_lines=lambda: _async_iter_lines(master),
-        )
-        lines = [line async for line in svc.rewrite_manifest("https://example.com/master.m3u8", upstream)]
-
-        assert "#EXT-X-STREAM-INF" in lines[1]
-        assert "/api/v1/youtube/proxy/manifest.m3u8?url=" in lines[2]
-        assert "/api/v1/youtube/proxy/manifest.m3u8?url=" in lines[4]
-
-
-# ---------------------------------------------------------------------------
-# Integration: Segment proxying with mocked httpx
-# ---------------------------------------------------------------------------
-
-class TestSegmentProxying:
-    @pytest.fixture
-    def svc(self):
-        from app.services.hls_proxy import HLSProxyService
-
-        return HLSProxyService()
-
-    @pytest.mark.asyncio
-    async def test_proxy_segment_returns_streaming_response(self, svc):
-        resp_mock = _make_mock_stream_response(
-            status_code=200,
-            headers={"content-type": "video/mp2t"},
-            aiter_bytes=lambda: _async_iter_bytes([b"\x47"] * 100),
-        )
-        client_mock = _make_mock_client(resp_mock)
-
-        with patch("app.services.hls_proxy.httpx.AsyncClient", return_value=client_mock):
-            from fastapi.responses import StreamingResponse
-
-            result = await svc.proxy_segment("https://cdn.example.com/0.ts")
-        assert isinstance(result, StreamingResponse)
-        assert result.media_type == "video/mp2t"
-        assert result.headers.get("access-control-allow-origin") == "*"
-
-
-# ---------------------------------------------------------------------------
-# Integration: Route tests
-# ---------------------------------------------------------------------------
-
-class TestProxyRoutes:
-    @pytest.fixture
-    def proxy_client(self):
-        from app.routers.youtube import router
-        from app.core.config import get_settings
-
-        get_settings.cache_clear()
-        from fastapi import FastAPI
-        from fastapi.testclient import TestClient
-
-        app = FastAPI()
-        app.include_router(router, prefix="/api/v1")
-        return TestClient(app)
-
-    def test_manifest_proxy_returns_cors_header(self, proxy_client):
-        upstream = _make_mock_stream_response(
-            status_code=200,
-            aiter_lines=lambda: _async_iter_lines("#EXTM3U\n#EXT-X-ENDLIST\n"),
-        )
-
-        with patch("app.routers.youtube.httpx.AsyncClient") as mock_client_cls:
-            mock_client = _make_mock_client(upstream)
-            mock_client_cls.return_value = mock_client
-
-            from urllib.parse import quote
-
-            encoded_url = quote("https://example.com/video.m3u8", safe="")
-            resp = proxy_client.get(f"/api/v1/youtube/proxy/manifest.m3u8?url={encoded_url}")
-
-        assert resp.status_code == 200
-        assert resp.headers.get("access-control-allow-origin") == "*"
-
-    def test_segment_proxy_returns_correct_content_type(self, proxy_client):
-        resp_mock = _make_mock_stream_response(
-            status_code=200,
-            headers={"content-type": "video/mp2t"},
-            aiter_bytes=lambda: _async_iter_bytes([b"\x47"] * 50),
-        )
-        client_mock = _make_mock_client(resp_mock)
-
-        with patch("app.services.hls_proxy.httpx.AsyncClient", return_value=client_mock):
-            from urllib.parse import quote
-
-            encoded_url = quote("https://cdn.example.com/0.ts", safe="")
-            resp = proxy_client.get(f"/api/v1/youtube/proxy/segment.ts?url={encoded_url}")
-
-        assert resp.status_code == 200
-        assert resp.headers.get("access-control-allow-origin") == "*"
-        assert resp.headers.get("content-type") == "video/mp2t"
-
-    def test_proxy_missing_url_parameter_returns_422(self, proxy_client):
-        resp = proxy_client.get("/api/v1/youtube/proxy/manifest.m3u8")
-        assert resp.status_code == 422
-
-    def test_proxy_upstream_404_returns_502(self, proxy_client):
-        upstream = _make_mock_stream_response(status_code=404)
-
-        with patch("app.routers.youtube.httpx.AsyncClient") as mock_client_cls:
-            mock_client = _make_mock_client(upstream)
-            mock_client_cls.return_value = mock_client
-
-            from urllib.parse import quote
-
-            encoded_url = quote("https://cdn.example.com/missing.ts", safe="")
-            resp = proxy_client.get(f"/api/v1/youtube/proxy/manifest.m3u8?url={encoded_url}")
-
-        # Route checks upstream status before streaming → raises 502
-        assert resp.status_code == 502
-
-
-# ---------------------------------------------------------------------------
-# Helpers
-# ---------------------------------------------------------------------------
-
-async def _async_iter_lines(text: str):
-    for line in text.split("\n"):
-        yield line
-
-
-async def _async_iter_bytes(chunks: list[bytes]):
-    for chunk in chunks:
-        yield chunk
diff --git a/backend/app/test/test_phase3_youtube_extract.py b/backend/app/test/test_phase3_youtube_extract.py
deleted file mode 100644
index bdfafa6..0000000
--- a/backend/app/test/test_phase3_youtube_extract.py
+++ /dev/null
@@ -1,477 +0,0 @@
-"""Phase 3.2 tests: YouTube URL extraction via yt-dlp.
-
-Covers:
-- POST /api/v1/youtube/extract — VOD, live, upcoming, invalid URL
-- Format selection: video-only ≤480p, best audio, HLS preference
-- URL caching: in-memory with TTL, expiry triggers re-extract
-- Proxy URL construction: upstream URL encoded in query param
-- Error handling: DownloadError → 400, timeout → 504, disabled → 503
-
-All yt-dlp external calls are mocked.
-"""
-import time
-from unittest.mock import MagicMock, patch
-
-import pytest
-from fastapi import FastAPI
-from fastapi.testclient import TestClient
-
-
-# ---------------------------------------------------------------------------
-# Helpers — fake yt-dlp format data
-# ---------------------------------------------------------------------------
-
-def _make_format(
-    format_id: str,
-    height: int | None = None,
-    vcodec: str = "none",
-    acodec: str = "none",
-    ext: str = "mp4",
-    protocol: str = "https",
-    url: str = "",
-    abr: float | None = None,
-    tbr: float | None = None,
-    resolution: str | None = None,
-) -> dict:
-    return {
-        "format_id": format_id,
-        "height": height,
-        "width": height * 16 // 9 if height else None,
-        "vcodec": vcodec,
-        "acodec": acodec,
-        "ext": ext,
-        "protocol": protocol,
-        "url": url or f"https://example.com/{format_id}.{ext}",
-        "abr": abr,
-        "tbr": tbr,
-        "resolution": resolution or (f"{height * 16 // 9}x{height}" if height else None),
-    }
-
-
-def _vod_info(video_id: str = "abc123") -> dict:
-    return {
-        "id": video_id,
-        "title": "Test VOD Video",
-        "thumbnail": "https://i.ytimg.com/vi/abc123/hqdefault.jpg",
-        "live_status": "not_live",
-        "duration": 300,
-        "formats": [
-            _make_format("137", height=1080, vcodec="avc1.640028", acodec="none", tbr=5000),
-            _make_format("136", height=720, vcodec="avc1.640028", acodec="none", tbr=2500),
-            _make_format("135", height=480, vcodec="avc1.640028", acodec="none", tbr=1200),
-            _make_format("134", height=360, vcodec="avc1.640028", acodec="none", tbr=600),
-            _make_format("133", height=240, vcodec="avc1.640028", acodec="none", tbr=300),
-            _make_format("140", acodec="mp4a.40.2", vcodec="none", abr=128),
-            _make_format("251", acodec="opus", vcodec="none", abr=160),
-            _make_format("18", height=360, vcodec="avc1.42001E", acodec="mp4a.40.2", tbr=500),
-        ],
-    }
-
-
-def _vod_info_hls(video_id: str = "abc123") -> dict:
-    return {
-        "id": video_id,
-        "title": "Test VOD with HLS",
-        "thumbnail": "https://i.ytimg.com/vi/abc123/hqdefault.jpg",
-        "live_status": "not_live",
-        "duration": 600,
-        "formats": [
-            _make_format("136", height=720, vcodec="avc1.640028", acodec="none", ext="m3u8", protocol="m3u8_native", tbr=2500),
-            _make_format("135", height=480, vcodec="avc1.640028", acodec="none", ext="m3u8", protocol="m3u8_native", tbr=1200),
-            _make_format("140", acodec="mp4a.40.2", vcodec="none", ext="m3u8", protocol="m3u8_native", abr=128),
-        ],
-    }
-
-
-def _live_info(video_id: str = "live999") -> dict:
-    return {
-        "id": video_id,
-        "title": "Live Stream Test",
-        "thumbnail": "https://i.ytimg.com/vi/live999/hqdefault_live.jpg",
-        "live_status": "is_live",
-        "duration": None,
-        "formats": [
-            _make_format("91", height=144, vcodec="avc1.42C00B", acodec="mp4a.40.5", ext="mp4", protocol="m3u8_native"),
-            _make_format("92", height=240, vcodec="avc1.4D4015", acodec="mp4a.40.5", ext="mp4", protocol="m3u8_native"),
-            _make_format("93", height=360, vcodec="avc1.4D401E", acodec="mp4a.40.2", ext="mp4", protocol="m3u8_native"),
-            _make_format("94", height=480, vcodec="avc1.4D401F", acodec="mp4a.40.2", ext="mp4", protocol="m3u8_native", tbr=1200),
-            _make_format("95", height=720, vcodec="avc1.4D401F", acodec="mp4a.40.2", ext="mp4", protocol="m3u8_native"),
-        ],
-    }
-
-
-def _upcoming_info(video_id: str = "up999") -> dict:
-    return {
-        "id": video_id,
-        "title": "Upcoming Stream",
-        "thumbnail": "https://i.ytimg.com/vi/up999/hqdefault.jpg",
-        "live_status": "is_upcoming",
-        "duration": None,
-        "formats": [],
-    }
-
-
-def _private_info(video_id: str = "priv99") -> dict:
-    import yt_dlp
-
-    raise yt_dlp.utils.DownloadError("Private video. Sign in if you've been granted access to this video")
-
-
-# ---------------------------------------------------------------------------
-# Mock helpers
-# ---------------------------------------------------------------------------
-
-def _make_mock_ydl(return_value: dict | Exception) -> MagicMock:
-    """Build a mock yt_dlp.YoutubeDL context manager with .extract_info."""
-    mock_instance = MagicMock()
-    if isinstance(return_value, Exception):
-        mock_instance.extract_info.side_effect = return_value
-    else:
-        mock_instance.extract_info.return_value = return_value
-    mock_ydl = MagicMock()
-    mock_ydl.__enter__.return_value = mock_instance
-    mock_ydl.__exit__.return_value = None
-    return mock_ydl
-
-
-# ---------------------------------------------------------------------------
-# Fixtures
-# ---------------------------------------------------------------------------
-
-@pytest.fixture
-def youtube_client(monkeypatch):
-    """FastAPI TestClient with youtube router mounted, cached settings cleared."""
-    from app.routers.youtube import router
-    from app.core.config import get_settings
-
-    get_settings.cache_clear()
-    monkeypatch.setenv("YOUTUBE_PROXY_ENABLED", "true")
-    get_settings.cache_clear()
-
-    app = FastAPI()
-    app.include_router(router, prefix="/api/v1")
-    return TestClient(app)
-
-
-# ---------------------------------------------------------------------------
-# Unit: Format selection
-# ---------------------------------------------------------------------------
-
-class TestFormatSelection:
-    def test_selects_best_video_at_or_under_480p(self):
-        from app.services.youtube_service import YouTubeService
-
-        svc = YouTubeService(timeout=30, cache_ttl=300)
-        formats = _vod_info()["formats"]
-        video, audio = svc._select_best_formats(formats)
-
-        assert video is not None
-        assert audio is not None
-        assert video["height"] == 480
-        assert video["vcodec"] != "none"
-        assert video["acodec"] == "none"
-        assert audio["acodec"] != "none"
-        assert audio["vcodec"] == "none"
-
-    def test_falls_back_to_lowest_video_if_no_480p(self):
-        from app.services.youtube_service import YouTubeService
-
-        svc = YouTubeService(timeout=30, cache_ttl=300)
-        formats = [
-            _make_format("137", height=1080, vcodec="avc1", acodec="none", tbr=5000),
-            _make_format("136", height=720, vcodec="avc1", acodec="none", tbr=2500),
-            _make_format("140", acodec="mp4a", vcodec="none", abr=128),
-        ]
-        video, audio = svc._select_best_formats(formats)
-
-        assert video is not None
-        assert video["height"] == 720  # Lowest available (no ≤480p exist)
-
-    def test_selects_highest_bitrate_audio(self):
-        from app.services.youtube_service import YouTubeService
-
-        svc = YouTubeService(timeout=30, cache_ttl=300)
-        formats = [
-            _make_format("137", height=480, vcodec="avc1", acodec="none", tbr=1200),
-            _make_format("140", acodec="mp4a", vcodec="none", abr=128),
-            _make_format("251", acodec="opus", vcodec="none", abr=160),
-            _make_format("250", acodec="opus", vcodec="none", abr=64),
-        ]
-        video, audio = svc._select_best_formats(formats)
-
-        assert audio is not None
-        assert audio["format_id"] == "251"  # Highest abr
-
-    def test_no_formats_raises(self):
-        from app.services.youtube_service import YouTubeService
-
-        svc = YouTubeService(timeout=30, cache_ttl=300)
-        with pytest.raises(ValueError, match="No streamable formats"):
-            svc._select_best_formats([])
-
-    def test_no_video_only_formats_falls_back_to_combined(self):
-        from app.services.youtube_service import YouTubeService
-
-        svc = YouTubeService(timeout=30, cache_ttl=300)
-        formats = [
-            _make_format("18", height=360, vcodec="avc1", acodec="mp4a", tbr=500),
-            _make_format("140", acodec="mp4a", vcodec="none", abr=128),
-        ]
-        video, audio = svc._select_best_formats(formats)
-
-        # Fallback: combined format as video
-        assert video is not None
-        assert video["format_id"] == "18"
-        assert audio is not None
-
-    def test_hls_preference_for_live(self):
-        from app.services.youtube_service import YouTubeService
-
-        svc = YouTubeService(timeout=30, cache_ttl=300)
-        formats = [
-            _make_format("135", height=480, vcodec="avc1", acodec="none", ext="mp4", protocol="https", tbr=1200),
-            _make_format("301", height=480, vcodec="avc1", acodec="none", ext="m3u8", protocol="m3u8_native", tbr=1200),
-            _make_format("140", acodec="mp4a", vcodec="none", ext="m3u8", protocol="m3u8_native", abr=128),
-        ]
-        video, audio = svc._select_best_formats(formats)
-
-        assert video["protocol"] == "m3u8_native"
-        assert audio["protocol"] == "m3u8_native"
-
-    def test_combined_only_all_combined_formats(self):
-        from app.services.youtube_service import YouTubeService
-
-        svc = YouTubeService(timeout=30, cache_ttl=300)
-        formats = [
-            _make_format("93", height=360, vcodec="avc1", acodec="mp4a", ext="mp4", protocol="m3u8_native"),
-            _make_format("94", height=480, vcodec="avc1", acodec="mp4a", ext="mp4", protocol="m3u8_native"),
-            _make_format("95", height=720, vcodec="avc1", acodec="mp4a", ext="mp4", protocol="m3u8_native"),
-            _make_format("96", height=1080, vcodec="avc1", acodec="mp4a", ext="mp4", protocol="m3u8_native"),
-        ]
-        video, audio = svc._select_best_formats(formats)
-
-        assert video["height"] == 480
-        assert audio["height"] == 480
-        assert video["url"] == audio["url"]
-
-
-# ---------------------------------------------------------------------------
-# Integration: Route + mocked yt-dlp
-# ---------------------------------------------------------------------------
-
-class TestYouTubeExtractVOD:
-    def test_extract_vod_returns_proxy_urls(self, youtube_client):
-        mock_ydl = _make_mock_ydl(_vod_info("abc123"))
-
-        with patch("app.services.youtube_service.yt_dlp.YoutubeDL", return_value=mock_ydl):
-            resp = youtube_client.post(
-                "/api/v1/youtube/extract",
-                json={"url": "https://www.youtube.com/watch?v=abc123"},
-            )
-
-        assert resp.status_code == 200
-        data = resp.json()
-        assert data["video_id"] == "abc123"
-        assert data["title"] == "Test VOD Video"
-        assert data["is_live"] is False
-        assert data["is_upcoming"] is False
-        assert data["video_proxy_url"] is not None
-        assert data["audio_proxy_url"] is not None
-        assert data["video_proxy_url"].startswith("/api/v1/youtube/proxy/")
-        assert data["thumbnail_url"] == "https://i.ytimg.com/vi/abc123/hqdefault.jpg"
-        assert len(data["formats"]) > 0
-
-    def test_extract_vod_hls_returns_manifest_proxy_urls(self, youtube_client):
-        mock_ydl = _make_mock_ydl(_vod_info_hls("abc123"))
-
-        with patch("app.services.youtube_service.yt_dlp.YoutubeDL", return_value=mock_ydl):
-            resp = youtube_client.post(
-                "/api/v1/youtube/extract",
-                json={"url": "https://www.youtube.com/watch?v=abc123"},
-            )
-
-        assert resp.status_code == 200
-        data = resp.json()
-        assert "manifest.m3u8?url=" in data["video_proxy_url"]
-        assert "manifest.m3u8?url=" in data["audio_proxy_url"]
-
-    def test_error_field_is_none_on_success(self, youtube_client):
-        mock_ydl = _make_mock_ydl(_vod_info())
-
-        with patch("app.services.youtube_service.yt_dlp.YoutubeDL", return_value=mock_ydl):
-            resp = youtube_client.post(
-                "/api/v1/youtube/extract",
-                json={"url": "https://www.youtube.com/watch?v=abc123"},
-            )
-
-        assert resp.status_code == 200
-        assert resp.json()["error"] is None
-
-
-class TestYouTubeExtractLive:
-    def test_extract_live_returns_is_live_true(self, youtube_client):
-        mock_ydl = _make_mock_ydl(_live_info())
-
-        with patch("app.services.youtube_service.yt_dlp.YoutubeDL", return_value=mock_ydl):
-            resp = youtube_client.post(
-                "/api/v1/youtube/extract",
-                json={"url": "https://www.youtube.com/watch?v=live999"},
-            )
-
-        assert resp.status_code == 200
-        data = resp.json()
-        assert data["video_id"] == "live999"
-        assert data["is_live"] is True
-        assert data["is_upcoming"] is False
-        assert data["video_proxy_url"] is not None
-        assert data["audio_proxy_url"] is not None
-
-    def test_live_combined_format_same_url_for_both(self, youtube_client):
-        mock_ydl = _make_mock_ydl(_live_info("combined_test"))
-
-        with patch("app.services.youtube_service.yt_dlp.YoutubeDL", return_value=mock_ydl):
-            resp = youtube_client.post(
-                "/api/v1/youtube/extract",
-                json={"url": "https://www.youtube.com/watch?v=combined_test"},
-            )
-
-        assert resp.status_code == 200
-        data = resp.json()
-        assert data["is_live"] is True
-        assert data["video_proxy_url"] == data["audio_proxy_url"]
-
-
-class TestYouTubeExtractUpcoming:
-    def test_extract_upcoming_returns_is_upcoming_true(self, youtube_client):
-        mock_ydl = _make_mock_ydl(_upcoming_info())
-
-        with patch("app.services.youtube_service.yt_dlp.YoutubeDL", return_value=mock_ydl):
-            resp = youtube_client.post(
-                "/api/v1/youtube/extract",
-                json={"url": "https://www.youtube.com/watch?v=up999"},
-            )
-
-        assert resp.status_code == 200
-        data = resp.json()
-        assert data["video_id"] == "up999"
-        assert data["is_upcoming"] is True
-        assert data["is_live"] is False
-        assert data["video_proxy_url"] is None
-        assert data["audio_proxy_url"] is None
-
-
-class TestYouTubeExtractErrors:
-    def test_private_video_returns_error_field(self, youtube_client):
-        import yt_dlp
-
-        exc = yt_dlp.utils.DownloadError("Private video")
-        mock_ydl = _make_mock_ydl(exc)
-
-        with patch("app.services.youtube_service.yt_dlp.YoutubeDL", return_value=mock_ydl):
-            resp = youtube_client.post(
-                "/api/v1/youtube/extract",
-                json={"url": "https://www.youtube.com/watch?v=priv99"},
-            )
-
-        assert resp.status_code == 200
-        data = resp.json()
-        assert data["error"] is not None
-        assert "Private video" in data["error"]
-
-    def test_po_token_error_invalidates_cache(self, monkeypatch):
-        import yt_dlp
-        from app.services.youtube_service import YouTubeService, _is_po_token_error
-
-        svc = YouTubeService(timeout=30, cache_ttl=300)
-        url = "https://www.youtube.com/watch?v=potest"
-
-        # Seed cache with a valid entry
-        svc._cache[url] = (100.0, {"video_id": "cached", "title": "Cached"})
-
-        # Mock yt-dlp to raise PO token error
-        exc = yt_dlp.utils.DownloadError("Sign in to confirm you're not a bot")
-        mock_ydl = _make_mock_ydl(exc)
-        with patch("app.services.youtube_service.yt_dlp.YoutubeDL", return_value=mock_ydl):
-            import asyncio
-            result = asyncio.new_event_loop().run_until_complete(svc.extract_streams(url))
-
-        assert result["error"] is not None
-        assert "not a bot" in result["error"]
-        # Cache should be invalidated — next extract would re-attempt
-        assert url not in svc._cache
-
-    def test_is_po_token_error_detection(self):
-        from app.services.youtube_service import _is_po_token_error
-
-        assert _is_po_token_error("Sign in to confirm you're not a bot")
-        assert _is_po_token_error("ERROR: [youtube] PO Token expired")
-        assert _is_po_token_error("bot detection triggered for this request")
-        assert not _is_po_token_error("Video unavailable")
-        assert not _is_po_token_error("Private video")
-
-    def test_disabled_proxy_returns_503(self, monkeypatch, youtube_client):
-        monkeypatch.setenv("YOUTUBE_PROXY_ENABLED", "false")
-        from app.core.config import get_settings
-
-        get_settings.cache_clear()
-
-        resp = youtube_client.post(
-            "/api/v1/youtube/extract",
-            json={"url": "https://www.youtube.com/watch?v=abc123"},
-        )
-        assert resp.status_code == 503
-
-
-class TestURLCaching:
-    def test_cached_result_not_re_extracted(self, youtube_client):
-        mock_ydl = _make_mock_ydl(_vod_info("cached1"))
-        instance = mock_ydl.__enter__.return_value
-
-        with patch("app.services.youtube_service.yt_dlp.YoutubeDL", return_value=mock_ydl):
-            r1 = youtube_client.post(
-                "/api/v1/youtube/extract",
-                json={"url": "https://www.youtube.com/watch?v=cached1"},
-            )
-            r2 = youtube_client.post(
-                "/api/v1/youtube/extract",
-                json={"url": "https://www.youtube.com/watch?v=cached1"},
-            )
-
-        assert r1.status_code == 200
-        assert r2.status_code == 200
-        assert r1.json()["video_id"] == r2.json()["video_id"]
-        assert instance.extract_info.call_count == 1  # Cached, not called twice
-
-    def test_cache_expiry_triggers_re_extract(self, monkeypatch):
-        from app.services.youtube_service import YouTubeService
-
-        svc = YouTubeService(timeout=30, cache_ttl=0)  # 0 TTL = immediate expiry
-
-        mock_ydl = _make_mock_ydl(_vod_info("exp1"))
-        instance = mock_ydl.__enter__.return_value
-
-        with patch("app.services.youtube_service.yt_dlp.YoutubeDL", return_value=mock_ydl):
-            import asyncio
-
-            asyncio.run(svc.extract_streams("https://www.youtube.com/watch?v=exp1"))
-            # Cache should be set but TTL=0 means expired
-            asyncio.run(svc.extract_streams("https://www.youtube.com/watch?v=exp1"))
-
-        assert instance.extract_info.call_count == 2
-
-
-class TestProxyURLConstruction:
-    def test_proxy_url_encodes_upstream_url(self):
-        from app.services.youtube_service import YouTubeService
-        from urllib.parse import quote, unquote
-
-        svc = YouTubeService(timeout=30, cache_ttl=300)
-
-        upstream = "https://manifest.googlevideo.com/123/hls_playlist.m3u8?id=abc&key=def"
-        proxy = svc._build_proxy_url(upstream)
-
-        assert proxy.startswith("/api/v1/youtube/proxy/manifest.m3u8?url=")
-        # Extract and decode the URL parameter
-        encoded = proxy.split("url=", 1)[1]
-        decoded = unquote(encoded)
-        assert decoded == upstream
diff --git a/backend/requirements.txt b/backend/requirements.txt
index 03d0532..12f620f 100644
--- a/backend/requirements.txt
+++ b/backend/requirements.txt
@@ -19,4 +19,3 @@ langchain-openai>=1.1.11,<1.2.0
 dashscope>=0.4.0
 aiofiles>=24.0.0
 zhconv>=1.4.0
-yt-dlp>=2024.0.0
diff --git a/development_plan.md b/development_plan.md
index 3521d18..692120b 100644
--- a/development_plan.md
+++ b/development_plan.md
@@ -135,51 +135,14 @@ User Question
 
 ---
 
-## Phase 3: YouTube Live Stream Proxy → ASR (5-6 days) ✅ Complete
-
-### Overview
-Proxy YouTube live streams and VODs through the backend, route audio into the existing ASR pipeline.
-
-### Backend Additions
-- YouTube URL extraction via yt-dlp (`POST /api/v1/youtube/extract`)
-- Format selection: video-only ≤480p + best audio (VOD), combined HLS (live)
-- HLS manifest proxy with line-by-line rewriting (`GET /api/v1/youtube/proxy/manifest.m3u8`)
-- TS segment proxying with CORS headers (`GET /api/v1/youtube/proxy/segment.ts`)
-- In-memory caching: 5 min TTL (live), 30 min TTL (VOD)
-- PO token expiration detection with cache invalidation
-
-### Frontend Additions
-- YouTubeInput component: URL validation, extraction, loading/error states
-- YouTubeVideoPlayer component: dual hls.js (video + hidden audio), thumbnail placeholder, LIVE badge
-- useYouTubeASR hook: AudioContext from audio element → WebSocket → DashScope ASR
-- LTTPage source toggle: Upload / YouTube tabs
-- hls.js integration with dynamic import and quality capping (≤480p)
-
-### Key Design Decisions
-- No iOS client needed (default yt-dlp extractor handles both VOD and live)
-- Dual-element architecture: `<video muted>` for display, `<audio hidden>` for AudioContext capture
-- HLS proxy rewrites all URLs (segments, sub-manifests, EXT-X-KEY URIs)
-- Upstream status checked BEFORE streaming (avoids "response already started" errors)
-- Both useVideoASR and useYouTubeASR return identical shapes for transparent integration
-
-### Architecture
-```
-YouTube URL → yt-dlp extract → HLS proxy → hls.js (video + audio)
-                                                 ↓
-                                          AudioContext → WebSocket → DashScope ASR → transcript
-```
-
----
-
 ## Development Timeline
 
 | Phase                        | Duration     | Key Deliverables | Status |
 |-----------------------------|--------------|------------------|--------|
 | Setup + Phase 1 Backend     | 3-4 days     | FastAPI + Chroma + Metadata + LLM client | ✅ Complete |
 | Phase 1 Frontend            | 2-3 days     | UI layout + text query flow | ✅ Complete |
-| Phase 2 Backend             | 4-5 days     | Video upload + WebSocket ASR + question extraction | ✅ Complete |
-| Phase 2 Frontend            | 3-4 days     | Video player + live transcript + auto/manual flow | ✅ Complete |
-| Phase 3 YouTube Proxy       | 5-6 days     | yt-dlp extraction + HLS proxy + YouTube ASR | ✅ Complete |
+| Phase 2 Backend             | 4-5 days     | Video upload + WebSocket ASR + question extraction | ⬜ Next |
+| Phase 2 Frontend            | 3-4 days     | Video player + live transcript + auto/manual flow | ⬜ Pending |
 | Testing & Polish            | 1-2 days     | End-to-end testing + deployment scripts | ⬜ Pending |
 
 **Total Estimated Effort**: 13-17 developer days (2-3 weeks)
@@ -201,5 +164,5 @@ YouTube URL → yt-dlp extract → HLS proxy → hls.js (video + audio)
 
 **File Information**  
 - Filename: `development_plan.md`  
-- Last Updated: May 2026
-- Status: Phase 1-3 Complete — YouTube proxy feature live
+- Last Updated: April 2026  
+- Status: Phase 1 Backend ✅, Phase 1 Frontend ✅ — Phase 2 next
diff --git a/frontend/package-lock.json b/frontend/package-lock.json
index 9b96486..b90a587 100644
--- a/frontend/package-lock.json
+++ b/frontend/package-lock.json
@@ -11,7 +11,6 @@
         "@tanstack/react-query": "^5.0.0",
         "autoprefixer": "^10.5.0",
         "axios": "^1.6.0",
-        "hls.js": "^1.6.16",
         "lucide-react": "^0.190.0",
         "pdfjs-dist": "^5.6.205",
         "react": "^18.2.0",
@@ -3802,12 +3801,6 @@
         "url": "https://opencollective.com/unified"
       }
     },
-    "node_modules/hls.js": {
-      "version": "1.6.16",
-      "resolved": "https://registry.npmjs.org/hls.js/-/hls.js-1.6.16.tgz",
-      "integrity": "sha512-VSIRpLfRwlAAdGL4wiTucx2ScRipo0ed1FBatWkyt832jC4CReKstga6yIhYVwGu9LOBjuX9wzmRMeQdBJtzEA==",
-      "license": "Apache-2.0"
-    },
     "node_modules/html-encoding-sniffer": {
       "version": "3.0.0",
       "resolved": "https://registry.npmjs.org/html-encoding-sniffer/-/html-encoding-sniffer-3.0.0.tgz",
diff --git a/frontend/package.json b/frontend/package.json
index 2a6a63c..c27ef15 100644
--- a/frontend/package.json
+++ b/frontend/package.json
@@ -13,7 +13,6 @@
     "@tanstack/react-query": "^5.0.0",
     "autoprefixer": "^10.5.0",
     "axios": "^1.6.0",
-    "hls.js": "^1.6.16",
     "lucide-react": "^0.190.0",
     "pdfjs-dist": "^5.6.205",
     "react": "^18.2.0",
diff --git a/frontend/src/components/YouTubeInput.tsx b/frontend/src/components/YouTubeInput.tsx
deleted file mode 100644
index 523021e..0000000
--- a/frontend/src/components/YouTubeInput.tsx
+++ /dev/null
@@ -1,110 +0,0 @@
-import React, { useState } from 'react'
-import { Loader2, AlertCircle, Play } from 'lucide-react'
-import { useYouTubeExtract } from '../lib/queries'
-import type { YouTubeStreamResponse } from '../types'
-
-export interface YouTubeInputProps {
-  onExtractSuccess: (data: YouTubeStreamResponse) => void
-  isDisabled?: boolean
-}
-
-const YOUTUBE_URL_REGEX = /^(https?:\/\/)?(www\.|m\.)?(youtube\.com\/watch\?v=|youtube\.com\/live\/|youtube\.com\/shorts\/|youtu\.be\/)[\w-]+(&.*)?$/i
-
-function isValidYouTubeUrl(url: string): boolean {
-  return YOUTUBE_URL_REGEX.test(url.trim())
-}
-
-export const YouTubeInput: React.FC<YouTubeInputProps> = ({ onExtractSuccess, isDisabled }) => {
-  const [url, setUrl] = useState('')
-  const [validationError, setValidationError] = useState<string | null>(null)
-
-  const extract = useYouTubeExtract()
-
-  const handleSubmit = (e: React.FormEvent) => {
-    e.preventDefault()
-    setValidationError(null)
-    extract.reset()
-
-    const trimmed = url.trim()
-    if (!trimmed) {
-      setValidationError('Please enter a YouTube URL')
-      return
-    }
-
-    if (!isValidYouTubeUrl(trimmed)) {
-      setValidationError('Please enter a valid YouTube URL (e.g., youtube.com/watch?v=... or youtu.be/...)')
-      return
-    }
-
-    extract.mutate(trimmed, {
-      onSuccess: (data: YouTubeStreamResponse) => {
-        if (data.error) {
-          setValidationError(data.error)
-          return
-        }
-        onExtractSuccess(data)
-      },
-      onError: (err: Error) => {
-        setValidationError(err.message)
-      },
-    })
-  }
-
-  const isLoading = extract.isPending
-  const hasError = validationError || extract.isError
-  const errorMessage = validationError || (extract.error?.message ?? null)
-
-  return (
-    <form onSubmit={handleSubmit} className="space-y-3">
-      <div className="flex gap-2">
-        <input
-          data-testid="youtube-url-input"
-          type="text"
-          value={url}
-          onChange={(e) => {
-            setUrl(e.target.value)
-            if (validationError) setValidationError(null)
-          }}
-          placeholder="Paste YouTube URL..."
-          disabled={isDisabled || isLoading}
-          className="flex-1 rounded border border-gray-300 px-3 py-2 text-sm focus:outline-none focus:ring-2 focus:ring-blue-500 focus:border-transparent disabled:bg-gray-100 disabled:cursor-not-allowed"
-        />
-        <button
-          data-testid="youtube-load-btn"
-          type="submit"
-          disabled={isDisabled || isLoading || !url.trim()}
-          className="shrink-0 px-4 py-2 bg-blue-600 text-white font-medium rounded hover:bg-blue-700 focus:outline-none focus:ring-2 focus:ring-blue-500 focus:ring-offset-2 disabled:opacity-50 disabled:cursor-not-allowed disabled:hover:bg-blue-600 transition-all duration-200 flex items-center gap-2"
-        >
-          {isLoading ? (
-            <>
-              <Loader2 className="w-4 h-4 animate-spin" />
-              Loading...
-            </>
-          ) : (
-            <>
-              <Play className="w-4 h-4" />
-              Load Stream
-            </>
-          )}
-        </button>
-      </div>
-
-      {isLoading && (
-        <div data-testid="youtube-loading" className="flex items-center gap-2 text-sm text-gray-600">
-          <Loader2 className="w-4 h-4 text-blue-600 animate-spin" />
-          Extracting stream info...
-        </div>
-      )}
-
-      {hasError && errorMessage && (
-        <div
-          data-testid="youtube-error"
-          className="p-3 bg-red-50 border border-red-200 rounded-lg flex items-start gap-2"
-        >
-          <AlertCircle className="w-4 h-4 text-red-500 shrink-0 mt-0.5" />
-          <div className="text-sm text-red-700">{errorMessage}</div>
-        </div>
-      )}
-    </form>
-  )
-}
diff --git a/frontend/src/components/YouTubeVideoPlayer.tsx b/frontend/src/components/YouTubeVideoPlayer.tsx
deleted file mode 100644
index 4741662..0000000
--- a/frontend/src/components/YouTubeVideoPlayer.tsx
+++ /dev/null
@@ -1,207 +0,0 @@
-import React, { forwardRef, useRef, useState, useEffect, useCallback } from 'react'
-import { Loader2, AlertCircle } from 'lucide-react'
-
-export interface YouTubeVideoPlayerProps {
-  videoProxyUrl: string
-  audioProxyUrl: string
-  thumbnailUrl: string | null
-  isLive: boolean
-  onAudioReady?: (audioElement: HTMLAudioElement) => void
-}
-
-const HLS_CONFIG = {
-  capLevelToPlayerSize: true,
-  maxBufferLength: 30,
-  maxMaxBufferLength: 60,
-}
-
-function capLevelsTo480(hls: any) {
-  if (!hls || !hls.levels) return
-  const maxIndex = hls.levels.length - 1
-  let capIndex = maxIndex
-  for (let i = maxIndex; i >= 0; i--) {
-    const level = hls.levels[i]
-    if (level.height && level.height <= 480) {
-      capIndex = i
-      break
-    }
-  }
-  hls.autoLevelCapping = capIndex
-}
-
-export const YouTubeVideoPlayer = forwardRef<HTMLVideoElement, YouTubeVideoPlayerProps>(
-  ({ videoProxyUrl, audioProxyUrl, thumbnailUrl, isLive, onAudioReady }, videoRef) => {
-    const internalVideoRef = useRef<HTMLVideoElement | null>(null)
-    const audioRef = useRef<HTMLAudioElement | null>(null)
-    const [isLoading, setIsLoading] = useState(true)
-    const [hasError, setHasError] = useState(false)
-    const [hasStarted, setHasStarted] = useState(false)
-
-    const setVideoRef = useCallback(
-      (node: HTMLVideoElement | null) => {
-        internalVideoRef.current = node
-        if (typeof videoRef === 'function') {
-          videoRef(node)
-        } else if (videoRef) {
-          (videoRef as React.MutableRefObject<HTMLVideoElement | null>).current = node
-        }
-      },
-      [videoRef]
-    )
-
-    useEffect(() => {
-      if (audioRef.current && onAudioReady) {
-        onAudioReady(audioRef.current)
-      }
-    }, [onAudioReady])
-
-    useEffect(() => {
-      let videoHls: any = null
-      let audioHls: any = null
-      let destroyed = false
-
-      const initHls = async () => {
-        const Hls = (await import('hls.js')).default
-        if (destroyed) return
-
-        if (!Hls.isSupported()) {
-          setHasError(true)
-          setIsLoading(false)
-          return
-        }
-
-        const videoEl = internalVideoRef.current
-        const audioEl = audioRef.current
-        if (!videoEl || !audioEl) return
-
-        videoHls = new Hls(HLS_CONFIG)
-        videoHls.loadSource(videoProxyUrl)
-        videoHls.attachMedia(videoEl)
-
-        videoHls.on(Hls.Events.MANIFEST_PARSED, () => {
-          capLevelsTo480(videoHls)
-        })
-
-        videoHls.on(Hls.Events.ERROR, (_event: any, data: any) => {
-          if (data.fatal) {
-            setHasError(true)
-            setIsLoading(false)
-          }
-        })
-
-        audioHls = new Hls(HLS_CONFIG)
-        audioHls.loadSource(audioProxyUrl)
-        audioHls.attachMedia(audioEl)
-
-        audioHls.on(Hls.Events.ERROR, (_event: any, data: any) => {
-          if (data.fatal) {
-            setHasError(true)
-            setIsLoading(false)
-          }
-        })
-
-        const handleCanPlay = () => {
-          setIsLoading(false)
-        }
-
-        videoEl.addEventListener('canplay', handleCanPlay)
-
-        return () => {
-          videoEl.removeEventListener('canplay', handleCanPlay)
-        }
-      }
-
-      initHls()
-
-      return () => {
-        destroyed = true
-        if (videoHls) {
-          videoHls.destroy()
-        }
-        if (audioHls) {
-          audioHls.destroy()
-        }
-      }
-    }, [videoProxyUrl, audioProxyUrl])
-
-    const handlePlay = () => {
-      setHasStarted(true)
-      const audioEl = audioRef.current
-      if (audioEl && audioEl.paused) {
-        audioEl.play().catch(() => {})
-      }
-    }
-
-    const handlePause = () => {
-      const audioEl = audioRef.current
-      if (audioEl && !audioEl.paused) {
-        audioEl.pause()
-      }
-    }
-
-    if (hasError) {
-      return (
-        <div
-          data-testid="youtube-error"
-          className="w-full max-h-60 rounded-lg bg-gray-100 border border-gray-200 flex flex-col items-center justify-center p-6 min-h-[200px]"
-        >
-          <AlertCircle className="w-10 h-10 text-red-500 mb-2" />
-          <div className="text-sm text-gray-600 font-medium">Failed to load stream</div>
-          <div className="text-xs text-gray-400 mt-1">Please try reloading the page.</div>
-        </div>
-      )
-    }
-
-    return (
-      <div className="relative w-full">
-        {isLive && (
-          <div
-            data-testid="youtube-live-badge"
-            className="absolute top-2 left-2 z-20 px-2 py-0.5 bg-red-600 text-white text-xs font-bold rounded"
-          >
-            LIVE
-          </div>
-        )}
-
-        {isLoading && (
-          <div
-            data-testid="youtube-loading"
-            className="absolute inset-0 z-10 bg-gray-100 rounded-lg flex flex-col items-center justify-center"
-          >
-            <Loader2 className="w-8 h-8 text-blue-600 animate-spin mb-2" />
-            <div className="text-sm text-gray-600">Loading stream...</div>
-          </div>
-        )}
-
-        {thumbnailUrl && !hasStarted && (
-          <img
-            data-testid="youtube-thumbnail"
-            src={thumbnailUrl}
-            alt="Video thumbnail"
-            className="absolute inset-0 z-[5] w-full max-h-60 rounded-lg object-cover bg-black"
-          />
-        )}
-
-        <video
-          ref={setVideoRef}
-          data-testid="youtube-video"
-          controls
-          muted
-          crossOrigin="anonymous"
-          className="w-full max-h-60 rounded-lg bg-black relative z-[1]"
-          onPlay={handlePlay}
-          onPause={handlePause}
-        />
-
-        <audio
-          ref={audioRef}
-          data-testid="youtube-audio"
-          crossOrigin="anonymous"
-          className="hidden"
-        />
-      </div>
-    )
-  }
-)
-
-YouTubeVideoPlayer.displayName = 'YouTubeVideoPlayer'
diff --git a/frontend/src/hooks/useYouTubeASR.ts b/frontend/src/hooks/useYouTubeASR.ts
deleted file mode 100644
index ab5472d..0000000
--- a/frontend/src/hooks/useYouTubeASR.ts
+++ /dev/null
@@ -1,178 +0,0 @@
-import { useState, useRef, useCallback, useEffect } from 'react'
-import type { ASRMessage, ASRStatus } from '../types'
-
-interface UseYouTubeASROptions {
-  videoId: string
-  videoElement: HTMLVideoElement | null
-  audioElement: HTMLAudioElement | null
-  language?: string
-  onFinalTranscript?: (text: string) => void
-}
-
-export function useYouTubeASR({
-  videoId,
-  videoElement,
-  audioElement,
-  language = 'yue',
-  onFinalTranscript,
-}: UseYouTubeASROptions) {
-  const [transcript, setTranscript] = useState('')
-  const [partialTranscript, setPartialTranscript] = useState('')
-  const [status, setStatus] = useState<ASRStatus>('idle')
-  const [isStreaming, setIsStreaming] = useState(false)
-
-  const wsRef = useRef<WebSocket | null>(null)
-  const audioContextRef = useRef<AudioContext | null>(null)
-  const processorRef = useRef<ScriptProcessorNode | null>(null)
-  const sourceRef = useRef<MediaElementAudioSourceNode | null>(null)
-  const isStreamingRef = useRef(false)
-  const graphSetupRef = useRef(false)
-  const transcriptRef = useRef('')
-  const lastStashRef = useRef('')
-  const onFinalTranscriptRef = useRef(onFinalTranscript)
-  onFinalTranscriptRef.current = onFinalTranscript
-
-  const getWSURL = useCallback(() => {
-    const protocol = window.location.protocol === 'https:' ? 'wss:' : 'ws:'
-    const host = window.location.host
-    const langParam = language !== 'auto' ? `?language=${language}` : ''
-    const backendHost = import.meta.env.VITE_WS_HOST ?? host
-    return `${protocol}//${backendHost}/ws/asr/${videoId}${langParam}`
-  }, [videoId, language])
-
-  const connectWebSocket = useCallback(() => {
-    const ws = new WebSocket(getWSURL())
-    wsRef.current = ws
-
-    ws.onopen = () => {
-      isStreamingRef.current = true
-      setIsStreaming(true)
-      setStatus('streaming')
-    }
-
-    ws.onmessage = (e) => {
-      const msg: ASRMessage = JSON.parse(e.data)
-      if (msg.is_final && msg.full_text) {
-        transcriptRef.current = msg.full_text
-        lastStashRef.current = ''
-        setTranscript(msg.full_text)
-        setPartialTranscript('')
-        onFinalTranscriptRef.current?.(msg.full_text)
-      } else if (msg.delta) {
-        transcriptRef.current += msg.delta
-        lastStashRef.current = (msg as any).stash || ''
-        setTranscript(transcriptRef.current)
-        setPartialTranscript(transcriptRef.current)
-      }
-    }
-
-    ws.onerror = (e) => {
-      console.error('[useYouTubeASR] WebSocket error:', e)
-      setStatus('error')
-    }
-    ws.onclose = () => {
-      isStreamingRef.current = false
-      setIsStreaming(false)
-      setStatus('disconnected')
-    }
-  }, [getWSURL])
-
-  const closeWebSocket = useCallback(() => {
-    wsRef.current?.close()
-    wsRef.current = null
-  }, [])
-
-  const startStreaming = useCallback(() => {
-    if (!audioElement) return
-    try {
-      setStatus('connecting')
-      audioContextRef.current?.resume()
-      closeWebSocket()
-      connectWebSocket()
-    } catch (err) {
-      console.error('[useYouTubeASR] startStreaming failed:', err)
-      setStatus('error')
-    }
-  }, [audioElement, closeWebSocket, connectWebSocket])
-
-  const stopStreaming = useCallback(() => {
-    isStreamingRef.current = false
-    setIsStreaming(false)
-    closeWebSocket()
-    setStatus('idle')
-    let currentText = transcriptRef.current.trim()
-    const stash = lastStashRef.current.trim()
-    if (stash && !currentText.endsWith(stash)) {
-      currentText += stash
-      transcriptRef.current = currentText
-    }
-    lastStashRef.current = ''
-    if (currentText) {
-      onFinalTranscriptRef.current?.(currentText)
-      setPartialTranscript('')
-    }
-  }, [closeWebSocket])
-
-  useEffect(() => {
-    if (!audioElement || graphSetupRef.current) return
-    try {
-      const audioContext = new AudioContext({ sampleRate: 16000 })
-      audioContextRef.current = audioContext
-
-      const source = audioContext.createMediaElementSource(audioElement)
-      sourceRef.current = source
-
-      const processor = audioContext.createScriptProcessor(4096, 1, 1)
-      processorRef.current = processor
-
-      processor.onaudioprocess = (e) => {
-        const float32Data = e.inputBuffer.getChannelData(0)
-        const outputData = e.outputBuffer.getChannelData(0)
-        outputData.set(float32Data)
-        if (!isStreamingRef.current) return
-        if (!wsRef.current || wsRef.current.readyState !== WebSocket.OPEN) return
-        wsRef.current.send(float32Data.buffer)
-      }
-
-      source.connect(processor)
-      processor.connect(audioContext.destination)
-      graphSetupRef.current = true
-    } catch (err) {
-      console.error('[useYouTubeASR] audio graph setup failed:', err)
-    }
-  }, [audioElement])
-
-  useEffect(() => {
-    return () => {
-      isStreamingRef.current = false
-      processorRef.current?.disconnect()
-      sourceRef.current?.disconnect()
-      wsRef.current?.close()
-      audioContextRef.current?.close()
-    }
-  }, [])
-
-  useEffect(() => {
-    if (!videoElement) return
-    const onPlay = () => startStreaming()
-    const onPause = () => stopStreaming()
-    const onEnded = () => stopStreaming()
-    videoElement.addEventListener('play', onPlay)
-    videoElement.addEventListener('pause', onPause)
-    videoElement.addEventListener('ended', onEnded)
-    return () => {
-      videoElement.removeEventListener('play', onPlay)
-      videoElement.removeEventListener('pause', onPause)
-      videoElement.removeEventListener('ended', onEnded)
-    }
-  }, [videoElement, startStreaming, stopStreaming])
-
-  return {
-    transcript,
-    partialTranscript,
-    isStreaming,
-    status,
-    startStreaming,
-    stopStreaming,
-  }
-}
diff --git a/frontend/src/lib/api.ts b/frontend/src/lib/api.ts
index 63b7f85..39ad983 100644
--- a/frontend/src/lib/api.ts
+++ b/frontend/src/lib/api.ts
@@ -1,5 +1,5 @@
 import axios from 'axios'
-import type { QueryRequest, QueryResponse, QueryStreamEvent, IngestResponse, DocumentListResponse, ChunkInfo, DeleteResponse, PromptProfileListResponse, PromptSetResponse, PromptUpdateRequest, PromptBatchUpdateRequest, PromptActivateResponse, PromptStatusResponse, ProfileExportData, ProfileImportResponse, QueryHistoryList, QueryHistoryDetail, HistoryStats, HistoryDeleteResponse, FullTranscriptResponse, VideoUploadResponse, YouTubeStreamResponse } from '../types'
+import type { QueryRequest, QueryResponse, QueryStreamEvent, IngestResponse, DocumentListResponse, ChunkInfo, DeleteResponse, PromptProfileListResponse, PromptSetResponse, PromptUpdateRequest, PromptBatchUpdateRequest, PromptActivateResponse, PromptStatusResponse, ProfileExportData, ProfileImportResponse, QueryHistoryList, QueryHistoryDetail, HistoryStats, HistoryDeleteResponse, FullTranscriptResponse, VideoUploadResponse } from '../types'
 
 const BASE_URL: string = import.meta.env.VITE_API_BASE_URL ?? 'http://localhost:8000/api/v1'
 
@@ -174,8 +174,3 @@ export const requestFullTranscript = async (videoId: string): Promise<FullTransc
   const resp = await apiClient.post<FullTranscriptResponse>(`/video/${videoId}/transcribe`)
   return resp.data
 }
-
-export const extractYouTubeStream = async (url: string): Promise<YouTubeStreamResponse> => {
-  const resp = await apiClient.post<YouTubeStreamResponse>('/youtube/extract', { url })
-  return resp.data
-}
diff --git a/frontend/src/lib/queries.tsx b/frontend/src/lib/queries.tsx
index 06da05b..cc6d36a 100644
--- a/frontend/src/lib/queries.tsx
+++ b/frontend/src/lib/queries.tsx
@@ -1,7 +1,7 @@
 import React from 'react'
 import { QueryClient, QueryClientProvider, useMutation, useQuery, useQueryClient } from '@tanstack/react-query'
-import { queryDocument, queryDocumentStream, ingestDocument, listDocuments, listChunks, deleteDocument, deleteChunk, listPromptProfiles, getPromptProfile, activatePromptProfile, updatePrompt, updateAllPrompts, resetPrompts, exportProfile, importProfile, listQueryHistory, getQueryHistoryDetail, deleteQueryHistory, clearQueryHistory, getHistoryStats, uploadVideo, extractYouTubeStream } from './api'
-import type { QueryRequest, QueryResponse, QueryStreamEvent, SourceMetadata, SubQuestionSources, IngestResponse, DocumentListResponse, ChunkInfo, DeleteResponse, PromptProfileListResponse, PromptSetResponse, PromptUpdateRequest, PromptBatchUpdateRequest, PromptActivateResponse, PromptStatusResponse, ProfileExportData, ProfileImportResponse, QueryHistoryList, QueryHistoryDetail, HistoryStats, HistoryDeleteResponse, VideoUploadResponse, YouTubeStreamResponse } from '../types'
+import { queryDocument, queryDocumentStream, ingestDocument, listDocuments, listChunks, deleteDocument, deleteChunk, listPromptProfiles, getPromptProfile, activatePromptProfile, updatePrompt, updateAllPrompts, resetPrompts, exportProfile, importProfile, listQueryHistory, getQueryHistoryDetail, deleteQueryHistory, clearQueryHistory, getHistoryStats, uploadVideo } from './api'
+import type { QueryRequest, QueryResponse, QueryStreamEvent, SourceMetadata, SubQuestionSources, IngestResponse, DocumentListResponse, ChunkInfo, DeleteResponse, PromptProfileListResponse, PromptSetResponse, PromptUpdateRequest, PromptBatchUpdateRequest, PromptActivateResponse, PromptStatusResponse, ProfileExportData, ProfileImportResponse, QueryHistoryList, QueryHistoryDetail, HistoryStats, HistoryDeleteResponse, VideoUploadResponse } from '../types'
 import { useState, useCallback, useRef } from 'react'
 
 export const queryClient = new QueryClient()
@@ -274,9 +274,3 @@ export const useVideoUpload = () => {
     mutationFn: ({ file, onProgress }) => uploadVideo(file, onProgress),
   })
 }
-
-export const useYouTubeExtract = () => {
-  return useMutation<YouTubeStreamResponse, Error, string>({
-    mutationFn: extractYouTubeStream,
-  })
-}
diff --git a/frontend/src/pages/LTTPage.tsx b/frontend/src/pages/LTTPage.tsx
index 182f967..392d6f5 100644
--- a/frontend/src/pages/LTTPage.tsx
+++ b/frontend/src/pages/LTTPage.tsx
@@ -1,9 +1,8 @@
 import React, { useState, useCallback, useEffect } from 'react'
-import { Loader2, AlertCircle, FileText, Upload, Youtube } from 'lucide-react'
+import { Loader2, AlertCircle, FileText } from 'lucide-react'
 import { Group, Panel, Separator } from 'react-resizable-panels'
 import { useQueryDocumentStream } from '../lib/queries'
 import { useVideoASR } from '../hooks/useVideoASR'
-import { useYouTubeASR } from '../hooks/useYouTubeASR'
 import { useFullTranscript } from '../hooks/useFullTranscript'
 import { getVideoUrl } from '../lib/api'
 import { QueryInput } from '../components/QueryInput'
@@ -11,23 +10,15 @@ import { ExtractedQuestionsDisplay } from '../components/ExtractedQuestionsDispl
 import { ResponsePanel } from '../components/ResponsePanel'
 import { VideoUpload } from '../components/VideoUpload'
 import { VideoPlayer } from '../components/VideoPlayer'
-import { YouTubeInput } from '../components/YouTubeInput'
-import { YouTubeVideoPlayer } from '../components/YouTubeVideoPlayer'
-import type { YouTubeStreamResponse } from '../types'
-
-type SourceType = 'upload' | 'youtube'
 
 export const LTTPage: React.FC = () => {
-  const [source, setSource] = useState<SourceType>('upload')
   const [currentVideoId, setCurrentVideoId] = useState<string | null>(null)
   const [queryText, setQueryText] = useState('')
   const [videoEl, setVideoEl] = useState<HTMLVideoElement | null>(null)
-  const [youtubeData, setYoutubeData] = useState<YouTubeStreamResponse | null>(null)
-  const [youtubeAudioEl, setYoutubeAudioEl] = useState<HTMLAudioElement | null>(null)
 
   const queryStream = useQueryDocumentStream()
 
-  const uploadASR = useVideoASR({
+  const asr = useVideoASR({
     videoId: currentVideoId ?? '',
     videoElement: videoEl,
     language: 'yue',
@@ -36,18 +27,6 @@ export const LTTPage: React.FC = () => {
     },
   })
 
-  const youtubeASR = useYouTubeASR({
-    videoId: youtubeData?.video_id ?? '',
-    videoElement: videoEl,
-    audioElement: youtubeAudioEl,
-    language: 'yue',
-    onFinalTranscript: (text) => {
-      setQueryText(text)
-    },
-  })
-
-  const asr = source === 'youtube' ? youtubeASR : uploadASR
-
   const ft = useFullTranscript({ videoId: currentVideoId ?? '' })
 
   useEffect(() => {
@@ -60,24 +39,6 @@ export const LTTPage: React.FC = () => {
     setCurrentVideoId(videoId)
   }, [])
 
-  const handleYouTubeExtractSuccess = useCallback((data: YouTubeStreamResponse) => {
-    setYoutubeData(data)
-    setQueryText('')
-  }, [])
-
-  const handleYouTubeAudioReady = useCallback((audioEl: HTMLAudioElement) => {
-    setYoutubeAudioEl(audioEl)
-  }, [])
-
-  const handleSourceChange = useCallback((newSource: SourceType) => {
-    if (newSource === source) return
-    if (newSource === 'upload') {
-      setYoutubeData(null)
-      setYoutubeAudioEl(null)
-    }
-    setSource(newSource)
-  }, [source])
-
   const handleQuerySubmit = (question: string): void => {
     queryStream.mutate({ question })
     setQueryText('')
@@ -91,14 +52,6 @@ export const LTTPage: React.FC = () => {
 
   const videoUrl = currentVideoId ? getVideoUrl(currentVideoId) : ''
 
-  const sourceTabClass = (active: boolean) =>
-    [
-      'flex items-center gap-2 px-4 py-2 text-sm font-medium rounded-lg transition-colors duration-200',
-      active
-        ? 'bg-blue-600 text-white'
-        : 'bg-gray-100 text-gray-600 hover:bg-gray-200',
-    ].join(' ')
-
   return (
     <div className="h-full bg-gray-50">
       <Group
@@ -112,88 +65,42 @@ export const LTTPage: React.FC = () => {
             <Group orientation="horizontal" id="ltt-upper-group" className="h-full">
               <Panel id="ltt-upper-left" minSize="30%" defaultSize={50}>
                 <div className="h-full p-4 overflow-hidden flex flex-col gap-3">
-                  <div data-testid="source-selector" className="flex gap-2 shrink-0">
-                    <button
-                      data-testid="source-tab-upload"
-                      className={sourceTabClass(source === 'upload')}
-                      onClick={() => handleSourceChange('upload')}
-                    >
-                      <Upload className="w-4 h-4" />
-                      Upload
-                    </button>
-                    <button
-                      data-testid="source-tab-youtube"
-                      className={sourceTabClass(source === 'youtube')}
-                      onClick={() => handleSourceChange('youtube')}
-                    >
-                      <Youtube className="w-4 h-4" />
-                      YouTube
-                    </button>
-                  </div>
-
-                  {source === 'upload' && (
-                    currentVideoId ? (
-                      <>
-                        <VideoPlayer ref={setVideoEl} src={videoUrl} />
-                        <button
-                          onClick={handleRequestFullTranscript}
-                          disabled={ft.isLoading}
-                          className="shrink-0 flex items-center justify-center gap-2 px-4 py-2 bg-gray-100 hover:bg-gray-200 text-gray-700 font-medium rounded-lg transition-colors duration-200 disabled:opacity-50 disabled:cursor-not-allowed"
+                  {currentVideoId ? (
+                    <>
+                      <VideoPlayer ref={setVideoEl} src={videoUrl} />
+                      <button
+                        onClick={handleRequestFullTranscript}
+                        disabled={ft.isLoading}
+                        className="shrink-0 flex items-center justify-center gap-2 px-4 py-2 bg-gray-100 hover:bg-gray-200 text-gray-700 font-medium rounded-lg transition-colors duration-200 disabled:opacity-50 disabled:cursor-not-allowed"
+                      >
+                        {ft.isLoading ? (
+                          <Loader2 className="w-4 h-4 animate-spin" />
+                        ) : (
+                          <FileText className="w-4 h-4" />
+                        )}
+                        <span>{ft.isLoading ? 'Transcribing...' : 'Full Transcript'}</span>
+                      </button>
+                      {ft.error && (
+                        <div
+                          data-testid="full-transcript-error"
+                          className="flex items-start gap-2 text-sm text-red-600"
                         >
-                          {ft.isLoading ? (
-                            <Loader2 className="w-4 h-4 animate-spin" />
-                          ) : (
-                            <FileText className="w-4 h-4" />
-                          )}
-                          <span>{ft.isLoading ? 'Transcribing...' : 'Full Transcript'}</span>
-                        </button>
-                        {ft.error && (
-                          <div
-                            data-testid="full-transcript-error"
-                            className="flex items-start gap-2 text-sm text-red-600"
-                          >
-                            <AlertCircle className="w-4 h-4 shrink-0 mt-0.5" />
-                            <span>{ft.error}</span>
-                          </div>
-                        )}
-                        {asr.status === 'error' && (
-                          <div
-                            data-testid="asr-error-indicator"
-                            className="flex items-center gap-2 text-xs text-red-600 bg-red-50 border border-red-200 rounded px-2 py-1"
-                          >
-                            <AlertCircle className="w-3 h-3" />
-                            <span>ASR error</span>
-                          </div>
-                        )}
-                      </>
-                    ) : (
-                      <VideoUpload onUploadSuccess={handleUploadSuccess} />
-                    )
-                  )}
-
-                  {source === 'youtube' && (
-                    youtubeData && youtubeData.video_proxy_url && youtubeData.audio_proxy_url ? (
-                      <>
-                        <YouTubeVideoPlayer
-                          videoProxyUrl={youtubeData.video_proxy_url}
-                          audioProxyUrl={youtubeData.audio_proxy_url}
-                          thumbnailUrl={youtubeData.thumbnail_url}
-                          isLive={youtubeData.is_live}
-                          onAudioReady={handleYouTubeAudioReady}
-                        />
-                        {asr.status === 'error' && (
-                          <div
-                            data-testid="asr-error-indicator"
-                            className="flex items-center gap-2 text-xs text-red-600 bg-red-50 border border-red-200 rounded px-2 py-1"
-                          >
-                            <AlertCircle className="w-3 h-3" />
-                            <span>ASR error</span>
-                          </div>
-                        )}
-                      </>
-                    ) : (
-                      <YouTubeInput onExtractSuccess={handleYouTubeExtractSuccess} />
-                    )
+                          <AlertCircle className="w-4 h-4 shrink-0 mt-0.5" />
+                          <span>{ft.error}</span>
+                        </div>
+                      )}
+                      {asr.status === 'error' && (
+                        <div
+                          data-testid="asr-error-indicator"
+                          className="flex items-center gap-2 text-xs text-red-600 bg-red-50 border border-red-200 rounded px-2 py-1"
+                        >
+                          <AlertCircle className="w-3 h-3" />
+                          <span>ASR error</span>
+                        </div>
+                      )}
+                    </>
+                  ) : (
+                    <VideoUpload onUploadSuccess={handleUploadSuccess} />
                   )}
                 </div>
               </Panel>
diff --git a/frontend/src/test/test_phase3_LTTPage_integration.test.tsx b/frontend/src/test/test_phase3_LTTPage_integration.test.tsx
deleted file mode 100644
index d2cfbce..0000000
--- a/frontend/src/test/test_phase3_LTTPage_integration.test.tsx
+++ /dev/null
@@ -1,197 +0,0 @@
-/**
- * Phase 3.5 integration tests: LTTPage YouTube source toggle and wiring.
- * Tests verify that the YouTube source tab renders, switching between sources
- * works, and components are conditionally rendered based on source state.
- */
-import React from 'react'
-import { render, screen, fireEvent } from '@testing-library/react'
-import { describe, it, expect, vi, beforeEach } from 'vitest'
-import { LTTPage } from '../pages/LTTPage'
-import type { YouTubeStreamResponse } from '../types'
-
-const mockUseYouTubeExtract = () => ({
-  mutate: vi.fn(),
-  isPending: false,
-  isError: false,
-  error: null,
-  reset: vi.fn(),
-})
-
-vi.mock('../lib/queries', () => ({
-  useQueryDocumentStream: () => ({
-    extractedQuestions: null,
-    answer: null,
-    sources: null,
-    subQuestionSources: null,
-    phase: 'idle',
-    historyId: null,
-    error: null,
-    mutate: vi.fn(),
-    reset: vi.fn(),
-  }),
-  useVideoUpload: () => ({
-    mutate: vi.fn(),
-    isPending: false,
-    isError: false,
-    error: null,
-    reset: vi.fn(),
-    data: null,
-  }),
-  useYouTubeExtract: () => mockUseYouTubeExtract(),
-}))
-
-vi.mock('../hooks/useVideoASR', () => ({
-  useVideoASR: () => ({
-    transcript: '',
-    partialTranscript: '',
-    isStreaming: false,
-    status: 'idle',
-    startStreaming: vi.fn(),
-    stopStreaming: vi.fn(),
-  }),
-}))
-
-vi.mock('../hooks/useYouTubeASR', () => ({
-  useYouTubeASR: () => ({
-    transcript: '',
-    partialTranscript: '',
-    isStreaming: false,
-    status: 'idle',
-    startStreaming: vi.fn(),
-    stopStreaming: vi.fn(),
-  }),
-}))
-
-vi.mock('../hooks/useFullTranscript', () => ({
-  useFullTranscript: () => ({
-    fullTranscript: '',
-    isLoading: false,
-    error: null,
-    requestFullTranscript: vi.fn(),
-  }),
-}))
-
-vi.mock('hls.js', () => ({
-  default: class MockHls {
-    static isSupported = () => true
-    static Events = {
-      MANIFEST_PARSED: 'manifestParsed',
-      ERROR: 'error',
-    }
-    on = vi.fn()
-    loadSource = vi.fn()
-    attachMedia = vi.fn()
-    destroy = vi.fn()
-    levels = [{ height: 720 }, { height: 480 }, { height: 360 }]
-    autoLevelCapping = -1
-  },
-}))
-
-vi.mock('../lib/api', () => ({
-  getVideoUrl: (id: string) => `http://localhost:8000/api/v1/video/${id}`,
-}))
-
-describe('LTTPage YouTube source toggle (Phase 3.5)', () => {
-  beforeEach(() => {
-    vi.clearAllMocks()
-  })
-
-  it('source selector renders with Upload and YouTube tabs', () => {
-    render(<LTTPage />)
-
-    expect(screen.getByTestId('source-selector')).toBeInTheDocument()
-    expect(screen.getByTestId('source-tab-upload')).toBeInTheDocument()
-    expect(screen.getByTestId('source-tab-youtube')).toBeInTheDocument()
-  })
-
-  it('default source is upload — VideoUpload visible', () => {
-    render(<LTTPage />)
-
-    expect(screen.getByTestId('video-dropzone')).toBeInTheDocument()
-  })
-
-  it('switching to youtube shows YouTubeInput', () => {
-    render(<LTTPage />)
-
-    fireEvent.click(screen.getByTestId('source-tab-youtube'))
-
-    expect(screen.getByTestId('youtube-url-input')).toBeInTheDocument()
-    expect(screen.queryByTestId('video-dropzone')).not.toBeInTheDocument()
-  })
-
-  it('switching back to upload shows VideoUpload', () => {
-    render(<LTTPage />)
-
-    fireEvent.click(screen.getByTestId('source-tab-youtube'))
-    expect(screen.getByTestId('youtube-url-input')).toBeInTheDocument()
-
-    fireEvent.click(screen.getByTestId('source-tab-upload'))
-    expect(screen.getByTestId('video-dropzone')).toBeInTheDocument()
-    expect(screen.queryByTestId('youtube-url-input')).not.toBeInTheDocument()
-  })
-
-  it('Full Transcript button hidden when YouTube source is active', () => {
-    render(<LTTPage />)
-
-    expect(screen.queryByText(/full transcript/i)).not.toBeInTheDocument()
-
-    fireEvent.click(screen.getByTestId('source-tab-youtube'))
-    expect(screen.queryByText(/full transcript/i)).not.toBeInTheDocument()
-  })
-
-  it('QueryInput renders regardless of source', () => {
-    render(<LTTPage />)
-
-    expect(screen.getByPlaceholderText(/ask a question/i)).toBeInTheDocument()
-
-    fireEvent.click(screen.getByTestId('source-tab-youtube'))
-    expect(screen.getByPlaceholderText(/ask a question/i)).toBeInTheDocument()
-  })
-
-  it('YouTubeVideoPlayer appears after successful extraction', () => {
-    const mockStreamData: YouTubeStreamResponse = {
-      video_id: 'testvid123',
-      title: 'Test Stream',
-      is_live: false,
-      is_upcoming: false,
-      video_proxy_url: 'http://localhost:8000/api/v1/youtube/proxy/manifest.m3u8?url=video',
-      audio_proxy_url: 'http://localhost:8000/api/v1/youtube/proxy/manifest.m3u8?url=audio',
-      thumbnail_url: 'http://localhost:8000/thumb.jpg',
-      formats: [],
-      error: null,
-    }
-
-    let capturedOnSuccess: ((data: YouTubeStreamResponse) => void) | null = null
-
-    vi.doMock('../components/YouTubeInput', () => {
-      const MockYouTubeInput = ({ onExtractSuccess }: { onExtractSuccess: (data: YouTubeStreamResponse) => void }) => {
-        capturedOnSuccess = onExtractSuccess
-        return <div data-testid="youtube-url-input">YouTube Input Mock</div>
-      }
-      MockYouTubeInput.displayName = 'YouTubeInput'
-      return { YouTubeInput: MockYouTubeInput }
-    })
-
-    vi.doMock('../components/YouTubeVideoPlayer', () => {
-      const MockPlayer = () => <div data-testid="youtube-video-player-mock">Player Mock</div>
-      MockPlayer.displayName = 'YouTubeVideoPlayer'
-      return { YouTubeVideoPlayer: MockPlayer }
-    })
-
-    vi.resetModules()
-
-    return import('../pages/LTTPage').then(async ({ LTTPage: FreshLTTPage }) => {
-      render(<FreshLTTPage />)
-
-      fireEvent.click(screen.getByTestId('source-tab-youtube'))
-      expect(screen.getByTestId('youtube-url-input')).toBeInTheDocument()
-
-      if (capturedOnSuccess) {
-        capturedOnSuccess(mockStreamData)
-      }
-
-      expect(await screen.findByTestId('youtube-video-player-mock')).toBeInTheDocument()
-      expect(screen.queryByTestId('youtube-url-input')).not.toBeInTheDocument()
-    })
-  })
-})
diff --git a/frontend/src/test/test_phase3_YouTubeInput.test.tsx b/frontend/src/test/test_phase3_YouTubeInput.test.tsx
deleted file mode 100644
index 385fedb..0000000
--- a/frontend/src/test/test_phase3_YouTubeInput.test.tsx
+++ /dev/null
@@ -1,149 +0,0 @@
-import React from 'react'
-import { render, screen, fireEvent, waitFor } from '@testing-library/react'
-import { describe, it, expect, vi, beforeEach } from 'vitest'
-import { YouTubeInput } from '../components/YouTubeInput'
-
-const mockMutate = vi.fn()
-const mockReset = vi.fn()
-
-let mockIsPending = false
-let mockIsError = false
-let mockError: Error | null = null
-
-vi.mock('../lib/queries', () => ({
-  useYouTubeExtract: () => ({
-    mutate: mockMutate,
-    isPending: mockIsPending,
-    isError: mockIsError,
-    error: mockError,
-    reset: mockReset,
-  }),
-}))
-
-describe('YouTubeInput (Phase 3.4)', () => {
-  const mockOnExtractSuccess = vi.fn()
-
-  beforeEach(() => {
-    vi.clearAllMocks()
-    mockMutate.mockClear()
-    mockReset.mockClear()
-    mockIsPending = false
-    mockIsError = false
-    mockError = null
-  })
-
-  it('renders URL input and Load Stream button', () => {
-    render(<YouTubeInput onExtractSuccess={mockOnExtractSuccess} />)
-
-    expect(screen.getByTestId('youtube-url-input')).toBeInTheDocument()
-    expect(screen.getByTestId('youtube-load-btn')).toBeInTheDocument()
-    expect(screen.getByTestId('youtube-load-btn')).toHaveTextContent(/load stream/i)
-  })
-
-  it('shows loading state during extraction', () => {
-    mockIsPending = true
-
-    render(<YouTubeInput onExtractSuccess={mockOnExtractSuccess} />)
-
-    expect(screen.getByTestId('youtube-loading')).toBeInTheDocument()
-    expect(screen.getByText(/extracting stream info/i)).toBeInTheDocument()
-  })
-
-  it('shows error state on failure', () => {
-    mockIsError = true
-    mockError = new Error('Extraction failed')
-
-    render(<YouTubeInput onExtractSuccess={mockOnExtractSuccess} />)
-
-    const errorEl = screen.getByTestId('youtube-error')
-    expect(errorEl).toBeInTheDocument()
-    expect(errorEl).toHaveTextContent(/extraction failed/i)
-  })
-
-  it('calls onExtractSuccess with data on success', async () => {
-    const mockResponse: import('../types').YouTubeStreamResponse = {
-      video_id: 'abc123',
-      title: 'Test Video',
-      is_live: false,
-      is_upcoming: false,
-      video_proxy_url: 'http://localhost:8000/api/v1/youtube/proxy/manifest.m3u8?url=vid',
-      audio_proxy_url: 'http://localhost:8000/api/v1/youtube/proxy/manifest.m3u8?url=aud',
-      thumbnail_url: 'http://localhost:8000/thumb.jpg',
-      formats: [],
-      error: null,
-    }
-
-    mockMutate.mockImplementation((_vars: any, options?: any) => {
-      if (options?.onSuccess) {
-        options.onSuccess(mockResponse)
-      }
-    })
-
-    render(<YouTubeInput onExtractSuccess={mockOnExtractSuccess} />)
-
-    const input = screen.getByTestId('youtube-url-input')
-    fireEvent.change(input, { target: { value: 'https://www.youtube.com/watch?v=abc123' } })
-
-    const button = screen.getByTestId('youtube-load-btn')
-    fireEvent.click(button)
-
-    await waitFor(() => {
-      expect(mockOnExtractSuccess).toHaveBeenCalledWith(mockResponse)
-    })
-  })
-
-  it('validates URL format and rejects non-YouTube URLs', () => {
-    render(<YouTubeInput onExtractSuccess={mockOnExtractSuccess} />)
-
-    const input = screen.getByTestId('youtube-url-input')
-    fireEvent.change(input, { target: { value: 'https://example.com/video' } })
-
-    const button = screen.getByTestId('youtube-load-btn')
-    fireEvent.click(button)
-
-    expect(screen.getByTestId('youtube-error')).toHaveTextContent(/valid youtube url/i)
-    expect(mockMutate).not.toHaveBeenCalled()
-  })
-
-  it('disables button when isDisabled is true', () => {
-    render(<YouTubeInput onExtractSuccess={mockOnExtractSuccess} isDisabled={true} />)
-
-    const input = screen.getByTestId('youtube-url-input')
-    expect(input).toBeDisabled()
-
-    const button = screen.getByTestId('youtube-load-btn')
-    expect(button).toBeDisabled()
-  })
-
-  it('accepts valid youtu.be short URL', async () => {
-    const mockResponse: import('../types').YouTubeStreamResponse = {
-      video_id: 'xyz789',
-      title: 'Short URL Video',
-      is_live: true,
-      is_upcoming: false,
-      video_proxy_url: 'http://localhost:8000/api/v1/youtube/proxy/manifest.m3u8?url=vid',
-      audio_proxy_url: 'http://localhost:8000/api/v1/youtube/proxy/manifest.m3u8?url=aud',
-      thumbnail_url: null,
-      formats: [],
-      error: null,
-    }
-
-    mockMutate.mockImplementation((_vars: any, options?: any) => {
-      if (options?.onSuccess) {
-        options.onSuccess(mockResponse)
-      }
-    })
-
-    render(<YouTubeInput onExtractSuccess={mockOnExtractSuccess} />)
-
-    const input = screen.getByTestId('youtube-url-input')
-    fireEvent.change(input, { target: { value: 'https://youtu.be/xyz789' } })
-
-    const button = screen.getByTestId('youtube-load-btn')
-    fireEvent.click(button)
-
-    await waitFor(() => {
-      expect(mockMutate).toHaveBeenCalledWith('https://youtu.be/xyz789', expect.any(Object))
-    })
-  })
-})
diff --git a/frontend/src/test/test_phase3_YouTubeVideoPlayer.test.tsx b/frontend/src/test/test_phase3_YouTubeVideoPlayer.test.tsx
deleted file mode 100644
index 8b562cb..0000000
--- a/frontend/src/test/test_phase3_YouTubeVideoPlayer.test.tsx
+++ /dev/null
@@ -1,168 +0,0 @@
-import React from 'react'
-import { render, screen } from '@testing-library/react'
-import { describe, it, expect, vi, beforeEach } from 'vitest'
-import { YouTubeVideoPlayer } from '../components/YouTubeVideoPlayer'
-
-vi.mock('hls.js', () => ({
-  default: class MockHls {
-    static isSupported = () => true
-    static Events = {
-      MANIFEST_PARSED: 'manifestParsed',
-      ERROR: 'error',
-    }
-    on = vi.fn()
-    loadSource = vi.fn()
-    attachMedia = vi.fn()
-    destroy = vi.fn()
-    levels = [{ height: 720 }, { height: 480 }, { height: 360 }]
-    autoLevelCapping = -1
-  },
-}))
-
-describe('YouTubeVideoPlayer (Phase 3.4)', () => {
-  const mockVideoProxyUrl = 'http://localhost:8000/api/v1/youtube/proxy/manifest.m3u8?url=video'
-  const mockAudioProxyUrl = 'http://localhost:8000/api/v1/youtube/proxy/manifest.m3u8?url=audio'
-  const mockThumbnailUrl = 'http://localhost:8000/thumb.jpg'
-
-  beforeEach(() => {
-    vi.clearAllMocks()
-  })
-
-  it('renders thumbnail when thumbnailUrl is provided', () => {
-    render(
-      <YouTubeVideoPlayer
-        videoProxyUrl={mockVideoProxyUrl}
-        audioProxyUrl={mockAudioProxyUrl}
-        thumbnailUrl={mockThumbnailUrl}
-        isLive={false}
-      />
-    )
-
-    const thumbnail = screen.getByTestId('youtube-thumbnail')
-    expect(thumbnail).toBeInTheDocument()
-    expect(thumbnail).toHaveAttribute('src', mockThumbnailUrl)
-  })
-
-  it('shows LIVE badge when isLive is true', () => {
-    render(
-      <YouTubeVideoPlayer
-        videoProxyUrl={mockVideoProxyUrl}
-        audioProxyUrl={mockAudioProxyUrl}
-        thumbnailUrl={null}
-        isLive={true}
-      />
-    )
-
-    const badge = screen.getByTestId('youtube-live-badge')
-    expect(badge).toBeInTheDocument()
-    expect(badge).toHaveTextContent('LIVE')
-  })
-
-  it('does not show LIVE badge when isLive is false', () => {
-    render(
-      <YouTubeVideoPlayer
-        videoProxyUrl={mockVideoProxyUrl}
-        audioProxyUrl={mockAudioProxyUrl}
-        thumbnailUrl={null}
-        isLive={false}
-      />
-    )
-
-    expect(screen.queryByTestId('youtube-live-badge')).not.toBeInTheDocument()
-  })
-
-  it('shows loading state initially', () => {
-    render(
-      <YouTubeVideoPlayer
-        videoProxyUrl={mockVideoProxyUrl}
-        audioProxyUrl={mockAudioProxyUrl}
-        thumbnailUrl={null}
-        isLive={false}
-      />
-    )
-
-    expect(screen.getByTestId('youtube-loading')).toBeInTheDocument()
-    expect(screen.getByText(/loading stream/i)).toBeInTheDocument()
-  })
-
-  it('forwards ref to video element', () => {
-    const ref = React.createRef<HTMLVideoElement>()
-    render(
-      <YouTubeVideoPlayer
-        ref={ref}
-        videoProxyUrl={mockVideoProxyUrl}
-        audioProxyUrl={mockAudioProxyUrl}
-        thumbnailUrl={null}
-        isLive={false}
-      />
-    )
-
-    expect(ref.current).not.toBeNull()
-    expect(ref.current?.tagName.toLowerCase()).toBe('video')
-  })
-
-  it('renders video element with correct attributes', () => {
-    render(
-      <YouTubeVideoPlayer
-        videoProxyUrl={mockVideoProxyUrl}
-        audioProxyUrl={mockAudioProxyUrl}
-        thumbnailUrl={null}
-        isLive={false}
-      />
-    )
-
-    const video = screen.getByTestId('youtube-video')
-    expect(video).toBeInTheDocument()
-    expect(video).toHaveAttribute('controls')
-    expect(video).toHaveProperty('muted', true)
-    expect(video).toHaveAttribute('crossOrigin', 'anonymous')
-    expect(video).toHaveClass('w-full')
-    expect(video).toHaveClass('max-h-60')
-  })
-
-  it('renders audio element hidden', () => {
-    render(
-      <YouTubeVideoPlayer
-        videoProxyUrl={mockVideoProxyUrl}
-        audioProxyUrl={mockAudioProxyUrl}
-        thumbnailUrl={null}
-        isLive={false}
-      />
-    )
-
-    const audio = screen.getByTestId('youtube-audio')
-    expect(audio).toBeInTheDocument()
-    expect(audio).toHaveAttribute('crossOrigin', 'anonymous')
-    expect(audio).toHaveClass('hidden')
-  })
-
-  it('renders without crashing with null thumbnail', () => {
-    render(
-      <YouTubeVideoPlayer
-        videoProxyUrl={mockVideoProxyUrl}
-        audioProxyUrl={mockAudioProxyUrl}
-        thumbnailUrl={null}
-        isLive={false}
-      />
-    )
-
-    expect(screen.getByTestId('youtube-video')).toBeInTheDocument()
-    expect(screen.queryByTestId('youtube-thumbnail')).not.toBeInTheDocument()
-  })
-
-  it('calls onAudioReady with audio element', () => {
-    const mockOnAudioReady = vi.fn()
-    render(
-      <YouTubeVideoPlayer
-        videoProxyUrl={mockVideoProxyUrl}
-        audioProxyUrl={mockAudioProxyUrl}
-        thumbnailUrl={null}
-        isLive={false}
-        onAudioReady={mockOnAudioReady}
-      />
-    )
-
-    expect(mockOnAudioReady).toHaveBeenCalledTimes(1)
-    expect(mockOnAudioReady.mock.calls[0][0]).toBeInstanceOf(HTMLAudioElement)
-  })
-})
diff --git a/frontend/src/test/test_phase3_useYouTubeASR.test.ts b/frontend/src/test/test_phase3_useYouTubeASR.test.ts
deleted file mode 100644
index 6ae7edb..0000000
--- a/frontend/src/test/test_phase3_useYouTubeASR.test.ts
+++ /dev/null
@@ -1,179 +0,0 @@
-/**
- * Phase 3.5 tests: useYouTubeASR hook state management.
- *
- * WebAudio (AudioContext, ScriptProcessorNode) and WebSocket are NOT available
- * in jsdom, so these tests verify state management, return shape, and cleanup
- * logic only. Full audio capture is covered by acceptance tests.
- */
-import { renderHook, act } from '@testing-library/react'
-import { describe, it, expect, vi, beforeEach } from 'vitest'
-import { useYouTubeASR } from '../hooks/useYouTubeASR'
-import type { ASRStatus } from '../types'
-
-beforeEach(() => {
-  vi.clearAllMocks()
-})
-
-describe('useYouTubeASR', () => {
-  it('test_initial_state', () => {
-    const { result } = renderHook(() =>
-      useYouTubeASR({
-        videoId: 'test-video-id',
-        videoElement: null,
-        audioElement: null,
-      })
-    )
-
-    expect(result.current.transcript).toBe('')
-    expect(result.current.partialTranscript).toBe('')
-    expect(result.current.isStreaming).toBe(false)
-    expect(result.current.status).toBe<ASRStatus>('idle')
-  })
-
-  it('test_returns_startStreaming_function', () => {
-    const { result } = renderHook(() =>
-      useYouTubeASR({
-        videoId: 'test-video-id',
-        videoElement: null,
-        audioElement: null,
-      })
-    )
-
-    expect(typeof result.current.startStreaming).toBe('function')
-  })
-
-  it('test_returns_stopStreaming_function', () => {
-    const { result } = renderHook(() =>
-      useYouTubeASR({
-        videoId: 'test-video-id',
-        videoElement: null,
-        audioElement: null,
-      })
-    )
-
-    expect(typeof result.current.stopStreaming).toBe('function')
-  })
-
-  it('test_stopStreaming_resets_state', () => {
-    const { result } = renderHook(() =>
-      useYouTubeASR({
-        videoId: 'test-video-id',
-        videoElement: null,
-        audioElement: null,
-      })
-    )
-
-    act(() => {
-      result.current.stopStreaming()
-    })
-
-    expect(result.current.status).toBe<ASRStatus>('idle')
-    expect(result.current.isStreaming).toBe(false)
-    expect(result.current.partialTranscript).toBe('')
-  })
-
-  it('test_startStreaming_without_elements_does_not_throw', () => {
-    const { result } = renderHook(() =>
-      useYouTubeASR({
-        videoId: 'test-video-id',
-        videoElement: null,
-        audioElement: null,
-      })
-    )
-
-    expect(() => {
-      act(() => {
-        result.current.startStreaming()
-      })
-    }).not.toThrow()
-  })
-
-  it('test_startStreaming_with_no_elements_sets_error_status', () => {
-    const { result } = renderHook(() =>
-      useYouTubeASR({
-        videoId: 'test-video-id',
-        videoElement: null,
-        audioElement: null,
-      })
-    )
-
-    act(() => {
-      result.current.startStreaming()
-    })
-
-    expect(['idle', 'error']).toContain(result.current.status)
-  })
-
-  it('test_cleanup_on_unmount', () => {
-    const { result, unmount } = renderHook(() =>
-      useYouTubeASR({
-        videoId: 'test-video-id',
-        videoElement: null,
-        audioElement: null,
-      })
-    )
-
-    expect(() => {
-      unmount()
-    }).not.toThrow()
-  })
-
-  it('test_accepts_language_option', () => {
-    const { result } = renderHook(() =>
-      useYouTubeASR({
-        videoId: 'test-video-id',
-        videoElement: null,
-        audioElement: null,
-        language: 'en',
-      })
-    )
-
-    expect(result.current.status).toBe<ASRStatus>('idle')
-  })
-
-  it('test_accepts_onFinalTranscript_callback', () => {
-    const onFinal = vi.fn()
-    const { result } = renderHook(() =>
-      useYouTubeASR({
-        videoId: 'test-video-id',
-        videoElement: null,
-        audioElement: null,
-        onFinalTranscript: onFinal,
-      })
-    )
-
-    expect(result.current.status).toBe<ASRStatus>('idle')
-  })
-
-  it('test_status_type_covers_all_states', () => {
-    const validStatuses: ASRStatus[] = ['idle', 'connecting', 'streaming', 'disconnected', 'error']
-    expect(validStatuses).toHaveLength(5)
-    expect(validStatuses).toContain('idle')
-    expect(validStatuses).toContain('connecting')
-    expect(validStatuses).toContain('streaming')
-    expect(validStatuses).toContain('disconnected')
-    expect(validStatuses).toContain('error')
-  })
-
-  it('test_startStreaming_with_audio_only', () => {
-    const mockAudioElement = {
-      crossOrigin: null,
-      addEventListener: vi.fn(),
-      removeEventListener: vi.fn(),
-    } as unknown as HTMLAudioElement
-
-    const { result } = renderHook(() =>
-      useYouTubeASR({
-        videoId: 'test-video-id',
-        videoElement: null,
-        audioElement: mockAudioElement,
-      })
-    )
-
-    expect(() => {
-      act(() => {
-        result.current.startStreaming()
-      })
-    }).not.toThrow()
-  })
-})
diff --git a/frontend/src/types/index.ts b/frontend/src/types/index.ts
index f26db02..527eb17 100644
--- a/frontend/src/types/index.ts
+++ b/frontend/src/types/index.ts
@@ -195,26 +195,3 @@ export interface VideoUploadResponse {
   size_bytes: number
   url: string
 }
-
-// Phase 3 — YouTube Stream types
-
-export interface YouTubeFormat {
-  format_id: string
-  url: string
-  resolution: string | null
-  is_audio_only: boolean
-  is_video_only: boolean
-  codec: string | null
-}
-
-export interface YouTubeStreamResponse {
-  video_id: string
-  title: string
-  is_live: boolean
-  is_upcoming: boolean
-  video_proxy_url: string | null
-  audio_proxy_url: string | null
-  thumbnail_url: string | null
-  formats: YouTubeFormat[]
-  error: string | null
-}