Worklog Week 7

Week 7 Objectives: Sprint 3 - Voice Integration

Integrate voice for speaking practice: streaming transcription (browser → Transcribe WebSocket), AI response generation, and text-to-speech.

Main Tasks:

DayTaskComplete
MonTranscribe Streaming:
- Presigned WebSocket URL generator (backend)
- Browser → Transcribe direct connection
- Real-time transcription handling		✅
TuePolly TTS:
- Neural voices integration (Joanna, Matthew)
- S3 storage + presigned URLs
- Audio synthesis endpoint		✅
WedVoice UI:
- Audio recording (MediaRecorder API)
- Streaming transcription integration
- Audio playback components
- Recording controls (start/stop/preview)		✅
ThuVoice Integration:
- Connect recording → transcription → AI → TTS flow
- Error handling for connection issues
- Audio format compatibility		✅
FriTesting:
- Test voice recording flow
- Test transcription accuracy
- Test audio playback
- Cross-browser testing (Chrome, Safari)		✅

Results:

1. Streaming Transcription:

  • ✅ Browser → Transcribe WebSocket (direct connection)
  • ✅ Presigned URL generator with SigV4 signing
  • ✅ Real-time transcription (200-400ms latency)
  • ✅ Error handling for connection issues

2. Text-to-Speech:

  • ✅ Polly neural voices (Joanna, Matthew)
  • ✅ S3 storage + presigned URLs (1h expiry)
  • ✅ MP3 format, 24kHz
  • ✅ Synchronous synthesis (500-800ms)

3. Voice UI:

  • ✅ Recording controls (start/stop/preview)
  • ✅ Audio visualization (waveform)
  • ✅ Playback controls
  • ✅ Mobile responsive

4. Testing:

  • ✅ Test with Chrome desktop
  • ✅ Test with Safari (iOS/macOS)
  • ✅ Test transcription accuracy with sample audio
  • ✅ Test end-to-end voice turn flow

Challenges:

  1. iOS Safari WebM format → Implemented fallback to WAV
  2. Transcribe WebSocket connection → Added retry logic
  3. Audio format compatibility → Format detection + conversion
  4. S3 presigned URL expiration → 1h expiry, regenerate on-demand

Next: Sprint 4 - Final testing, deployment, demo