Root cause: PcmPlayer called openPlayer() without audio session config,
so Android defaulted to earpiece-only mode. When the mic was actively
recording, playback was silently suppressed — the agent's TTS audio was
sent successfully over WebSocket but never reached the speaker.
Changes:
1. PcmPlayer (pcm_player.dart):
- Added audio_session package for proper audio session management
- Configure AudioSession with playAndRecord category so mic + speaker
work simultaneously
- Set voiceCommunication usage to enable Android hardware AEC (echo
cancellation) — prevents feedback loops when speaker is active
- defaultToSpeaker routes output to loudspeaker instead of earpiece
- Restored setSpeakerOn() method stub (used by UI toggle)
2. AgentCallPage (agent_call_page.dart):
- Fixed fire-and-forget bug: _pcmPlayer.feed() returns Future but was
called without await, causing interleaved feedUint8FromStream calls
- Added _feedChain serializer to guarantee sequential audio feeding
3. Dependencies:
- Added audio_session package to pubspec.yaml
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Replace traditional on-device speech_to_text with a modern pipeline:
- Record audio via `record` package with hardware noise suppression
- Apply GTCRN neural denoising (sherpa-onnx, ICASSP 2024, 48K params)
- Trim silence, POST to backend /voice/transcribe (faster-whisper)
Changes:
- Add /transcribe endpoint to voice-service for audio file upload
- Add SpeechEnhancer wrapper for sherpa-onnx GTCRN model (523KB)
- Rewrite chat_page.dart voice input: record → denoise → transcribe
- Keep NoiseReducer.trimSilence for silence removal only
- Upgrade record to v6.2.0, add sherpa_onnx, path_provider
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
hailin