legco_ai_assistant/.examples/README.md

Alibaba Cloud DashScope ASR — Reference Examples

Adapted from /mnt/c/Users/woody/Documents/projects/voice input/ (Cantonese voice-to-text web app).

Files

File	What	Language
alibaba_asr_backend.py	FastAPI WebSocket proxy to DashScope realtime ASR	Python
alibaba_asr_frontend_vanilla.html	Browser audio capture + WebSocket (vanilla JS)	HTML/JS
alibaba_asr_frontend_react.tsx	React/TS hook + component for audio capture	TypeScript/React

Architecture

Browser (Float32 PCM, 16kHz mono)
  │  WebSocket: send(float32Data.buffer)
  ▼
FastAPI Backend (/ws/asr/{video_id})
  │  Convert Float32 → S16_LE → base64
  ▼
Alibaba Cloud DashScope (wss://dashscope-intl.aliyuncs.com/api-ws/v1/realtime)
  │  Model: qwen3-asr-flash-realtime
  ▼  Language: yue (Cantonese)
Transcript JSON → Browser

Key Details

• Audio format: Float32 PCM, 16kHz, mono (browser) → S16_LE PCM, 16kHz, mono, base64 (DashScope)
• Model: qwen3-asr-flash-realtime (WebSocket realtime, unlimited duration)
• Endpoint: wss://dashscope-intl.aliyuncs.com/api-ws/v1/realtime
• SDK: pip install dashscope>=0.4.0
• Cantonese: Language code yue (works natively with DashScope)
• VAD: Server-side (Alibaba Cloud handles voice activity detection)
• Pricing: ~$0.00009/second
• Features: Punctuation, ITN, filler word filtering, multi-language auto-detect

Dependencies

# Python
dashscope>=0.4.0
openai>=1.52.0
zhconv>=1.4.0       # Simplified → Traditional Chinese (optional)

# No additional JS deps needed — native Web APIs only:
#   WebSocket, AudioContext, ScriptProcessorNode, getUserMedia