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feat(voice-input): improve STT locale selection and Android handling

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This commit is contained in:
cogwheel0
2025-11-27 19:48:25 +05:30
parent d092bb2e44
commit f9574dfec0
2 changed files with 131 additions and 22 deletions
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151
lib/features/chat/services/voice_input_service.dart
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@@ -3,6 +3,7 @@ import 'dart:convert';
import 'dart:io' show Platform;
import 'dart:typed_data';
import 'package:flutter/services.dart';
import 'package:flutter/widgets.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'package:record/record.dart';
@@ -36,7 +37,7 @@ class VoiceInputService {
static const Duration _localeFetchTimeout = Duration(seconds: 2);
static const String _backgroundSttStreamId = 'voice-input-stt';
final VadHandler _vadHandler = VadHandler.create();
VadHandler? _vadHandler;
final SpeechToText _speech = SpeechToText();
final AudioRecorder _microphonePermissionProbe = AudioRecorder();
final ApiService? _api;
@@ -53,6 +54,7 @@ class VoiceInputService {
Future<void>? _startingLocalStt;
StreamController<String>? _textStreamController;
String _currentText = '';
bool _receivedFinalResult = false;
StreamController<int>? _intensityController;
Stream<int> get intensityStream =>
_intensityController?.stream ?? const Stream<int>.empty();
@@ -124,11 +126,32 @@ class VoiceInputService {
// properly close the stream so voice call service can restart
if (wasActive && _isListening && !_usingServerStt) {
debugPrint('Platform stopped listening, closing stream');
unawaited(_stopListening());
// On Android, the 'done' status often fires BEFORE the final result
// callback arrives. Wait for the final result to avoid cutting off
// the last word.
if (Platform.isAndroid && !_receivedFinalResult) {
_waitForFinalResultThenStop();
} else {
unawaited(_stopListening());
}
}
}
}
/// Waits briefly for Android to deliver the final STT result before stopping.
void _waitForFinalResultThenStop() {
Future(() async {
// Wait up to 300ms for the final result to arrive
for (var i = 0; i < 6; i++) {
await Future.delayed(const Duration(milliseconds: 50));
if (_receivedFinalResult || !_isListening) break;
}
if (_isListening) {
await _stopListening();
}
});
}
void _handleSttError(dynamic error) {
debugPrint('Local STT Error: $error');
final errorStr = error.toString().toLowerCase();
@@ -234,13 +257,29 @@ class VoiceInputService {
if (sttLocales.isEmpty) {
return;
}
// Map speech_to_text LocaleName to our own LocaleName class
_locales = sttLocales
.map((loc) => LocaleName(loc.localeId, loc.name))
.toList();
_usingFallbackLocales = false;
final match = _matchLocale(deviceTag);
// Prefer the STT engine's own system locale when available, since
// it may differ from Flutter's UI locale on some Android devices.
final systemLocale = await _speech.systemLocale();
final systemTag = systemLocale?.localeId;
final tagForMatch = (systemTag != null && systemTag.isNotEmpty)
? systemTag
: deviceTag;
final match = _matchLocale(tagForMatch);
_selectedLocaleId = match.localeId;
debugPrint(
'VoiceInputService: deviceTag=$deviceTag, '
'systemLocale=$systemTag, '
'selectedLocaleId=$_selectedLocaleId',
);
} catch (_) {
// Some engines may not support locale listing
}
@@ -359,15 +398,15 @@ class VoiceInputService {
final prevLen = _currentText.length;
_currentText = result.recognizedWords;
_textStreamController?.add(_currentText);
if (result.finalResult) {
_receivedFinalResult = true;
}
final delta = (_currentText.length - prevLen).clamp(0, 50);
final mapped = (delta / 5.0).ceil();
_lastIntensity = mapped.clamp(0, 10);
try {
_intensityController?.add(_lastIntensity);
} catch (_) {}
if (result.finalResult) {
unawaited(_stopListening());
}
}
Future<Stream<String>> startListening() async {
@@ -388,10 +427,19 @@ class VoiceInputService {
_textStreamController = StreamController<String>.broadcast();
_currentText = '';
_isListening = true;
_receivedFinalResult = false;
_intensityController = StreamController<int>.broadcast();
_lastIntensity = 0;
_usingServerStt = false;
// Optional haptic feedback when listening starts
final hapticsEnabled = _ref?.read(hapticEnabledProvider) ?? false;
if (hapticsEnabled) {
try {
HapticFeedback.heavyImpact();
} catch (_) {}
}
_startIntensityDecayTimer();
final bool canUseLocal = _localSttAvailable;
@@ -489,12 +537,11 @@ class VoiceInputService {
Future<void> _stopListening() async {
if (!_isListening) return;
_isListening = false;
_autoStopTimer?.cancel();
_autoStopTimer = null;
if (_usingServerStt) {
_isListening = false;
await _stopVadRecording();
final samples = _vadPendingSamples;
_vadPendingSamples = null;
@@ -502,7 +549,17 @@ class VoiceInputService {
await _processVadSamples(samples);
}
} else {
// On Android, stop() triggers a final result with any buffered words.
// Keep _isListening true until after stop() so _handleSttResult accepts it.
await _stopLocalStt();
// Wait for Android's STT engine to deliver the final result callback
if (Platform.isAndroid && !_receivedFinalResult) {
for (var i = 0; i < 6; i++) {
await Future.delayed(const Duration(milliseconds: 50));
if (_receivedFinalResult) break;
}
}
_isListening = false;
if (_currentText.isNotEmpty) {
_textStreamController?.add(_currentText);
}
@@ -552,7 +609,11 @@ class VoiceInputService {
}
Future<void> _startServerRecording() async {
await _setupVadStreams();
// Create a fresh VadHandler for this session to avoid reusing any
// internal AudioRecorder that may be in a bad state after errors.
final vad = VadHandler.create();
_vadHandler = vad;
await _setupVadStreams(vad);
final settings = _ref?.read(appSettingsProvider);
final silenceMs = settings?.voiceSilenceDuration ?? 2000;
final redemptionFrames = _silenceDurationToFrames(
@@ -561,7 +622,7 @@ class VoiceInputService {
);
try {
await _vadHandler.startListening(
await vad.startListening(
frameSamples: _vadFrameSamples,
model: 'v5',
minSpeechFrames: _vadMinSpeechFrames,
@@ -581,22 +642,59 @@ class VoiceInputService {
noiseSuppress: true,
androidConfig: AndroidRecordConfig(
audioSource: AndroidAudioSource.voiceRecognition,
audioManagerMode: AudioManagerMode.modeInCommunication,
speakerphone: true,
// Use normal mode instead of modeInCommunication to avoid
// audio routing conflicts with TTS playback after recording stops.
audioManagerMode: AudioManagerMode.modeNormal,
speakerphone: false,
manageBluetooth: true,
useLegacy: false,
),
),
);
} catch (error) {
// If starting the audio stream fails (e.g. recorder disposed),
// drop this handler so the next session gets a clean instance.
if (identical(_vadHandler, vad)) {
_vadHandler = null;
}
// Known Android issue: the underlying AudioRecorder can be in a bad
// state after audio focus changes triggered by TTS playback. When
// this happens and local STT is available, transparently fall back
// to on-device STT instead of failing the entire voice turn.
final canFallbackToLocal = _localSttAvailable && !prefersServerOnly;
if (error is PlatformException &&
error.code == 'record' &&
(error.message ?? '').contains(
'Recorder has not yet been created or has already been disposed.',
) &&
canFallbackToLocal &&
_isListening) {
debugPrint(
'VadHandler.startListening failed due to recorder error – '
'falling back to local STT.',
);
_usingServerStt = false;
try {
await _stopVadRecording();
} catch (_) {}
try {
await _startLocalRecognition(allowOnlineFallback: !prefersDeviceOnly);
return;
} catch (fallbackError) {
_textStreamController?.addError(fallbackError);
rethrow;
}
}
_textStreamController?.addError(error);
rethrow;
}
}
Future<void> _setupVadStreams() async {
Future<void> _setupVadStreams(VadHandler vad) async {
await _vadSpeechEndSub?.cancel();
_vadSpeechEndSub = _vadHandler.onSpeechEnd.listen((samples) {
_vadSpeechEndSub = vad.onSpeechEnd.listen((samples) {
if (!_isListening || !_usingServerStt) return;
if (samples.isEmpty) return;
_vadPendingSamples = samples;
@@ -606,7 +704,7 @@ class VoiceInputService {
});
await _vadFrameSub?.cancel();
_vadFrameSub = _vadHandler.onFrameProcessed.listen((frameData) {
_vadFrameSub = vad.onFrameProcessed.listen((frameData) {
if (!_isListening) return;
final intensity = _intensityFromVadFrame(frameData.frame);
_lastIntensity = intensity;
@@ -616,7 +714,7 @@ class VoiceInputService {
});
await _vadErrorSub?.cancel();
_vadErrorSub = _vadHandler.onError.listen((message) {
_vadErrorSub = vad.onError.listen((message) {
_textStreamController?.addError(Exception(message));
if (_isListening) {
unawaited(_stopListening());
@@ -625,9 +723,12 @@ class VoiceInputService {
}
Future<void> _stopVadRecording() async {
try {
await _vadHandler.stopListening();
} catch (_) {}
final vad = _vadHandler;
if (vad != null) {
try {
await vad.stopListening();
} catch (_) {}
}
await _vadSpeechEndSub?.cancel();
_vadSpeechEndSub = null;
await _vadFrameSub?.cancel();
@@ -636,6 +737,16 @@ class VoiceInputService {
_vadErrorSub = null;
}
Future<void> _disposeVadHandler() async {
final vad = _vadHandler;
_vadHandler = null;
if (vad != null) {
try {
await vad.dispose();
} catch (_) {}
}
}
Future<void> _processVadSamples(List<double> samples) async {
final api = _api;
if (api == null) return;
@@ -861,7 +972,7 @@ class VoiceInputService {
void dispose() {
stopListening();
unawaited(_vadHandler.dispose());
unawaited(_disposeVadHandler());
unawaited(_microphonePermissionProbe.dispose());
try {
_speech.stop();