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125 lines
3.7 KiB
125 lines
3.7 KiB
import 'dart:async';
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import 'dart:typed_data';
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import 'package:record/record.dart';
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import '../../core/utils/logger.dart';
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import 'pcm_stream_player.dart';
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/// 手机麦克风的 PCM 流采集，专供百炼上行使用。
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///
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/// `record` 的 `startStream` 回调块大小由平台决定（Android 通常几百字节到 2KB），
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/// 百炼建议每包 ~100ms（16k/16bit/单声道 = 3200 字节），所以这里做一层重新分包：
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/// 攒够 [_packetBytes] 再发一包，尾巴不足一包的在 [stop] 时补发。
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class MicPcmStreamer {
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MicPcmStreamer({this.sampleRate = 16000});
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static const String _tag = 'MicPcmStreamer';
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final int sampleRate;
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/// 100ms 一包
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int get _packetBytes => sampleRate * 2 ~/ 10;
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final AudioRecorder _recorder = AudioRecorder();
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StreamSubscription<Uint8List>? _sub;
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final _buffer = BytesBuilder(copy: false);
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final _packets = StreamController<Uint8List>.broadcast();
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/// 重新分包后的上行 PCM
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Stream<Uint8List> get packets => _packets.stream;
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final _levelCtl = StreamController<double>.broadcast();
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/// 麦克风实时音量（0~1），UI 音浪用
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Stream<double> get level => _levelCtl.stream;
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bool _running = false;
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bool get isRunning => _running;
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Future<bool> hasPermission() => _recorder.hasPermission();
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Future<bool> start() async {
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if (_running) return true;
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try {
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if (!await _recorder.hasPermission()) {
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Logger.w(_tag, '没有麦克风权限');
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return false;
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}
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final stream = await _recorder.startStream(
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RecordConfig(
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encoder: AudioEncoder.pcm16bits,
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sampleRate: sampleRate,
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numChannels: 1,
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// 语音助手场景：开回声消除和降噪，否则外放播报会被自己的麦克风收回去，
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// duplex 模式下会直接把服务端 VAD 打乱
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echoCancel: true,
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noiseSuppress: true,
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),
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);
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_running = true;
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_buffer.clear();
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_sub = stream.listen(
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_onChunk,
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onError: (e) => Logger.e(_tag, '录音流错误: $e'),
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);
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Logger.i(_tag, '麦克风采集启动 ${sampleRate}Hz');
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return true;
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} catch (e) {
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Logger.e(_tag, '麦克风采集启动失败: $e');
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_running = false;
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return false;
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}
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}
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void _onChunk(Uint8List chunk) {
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if (chunk.isEmpty) return;
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if (!_levelCtl.isClosed) _levelCtl.add(PcmStreamPlayer.rmsLevel(chunk));
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_buffer.add(chunk);
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while (_buffer.length >= _packetBytes) {
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// BytesBuilder 只能整体取出，取出后把余量放回去
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final all = _buffer.takeBytes();
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var offset = 0;
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while (all.length - offset >= _packetBytes) {
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_emit(Uint8List.sublistView(all, offset, offset + _packetBytes));
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offset += _packetBytes;
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}
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if (offset < all.length) {
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_buffer.add(Uint8List.sublistView(all, offset));
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}
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}
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}
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void _emit(Uint8List packet) {
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if (_packets.isClosed) return;
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// sublistView 是原缓冲的视图，下游可能异步持有，复制一份避免被后续写入覆盖
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_packets.add(Uint8List.fromList(packet));
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}
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Future<void> stop() async {
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if (!_running) return;
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_running = false;
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await _sub?.cancel();
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_sub = null;
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try {
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await _recorder.stop();
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} catch (e) {
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Logger.w(_tag, '停止录音异常: $e');
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}
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// 尾包补发，否则最后不足 100ms 的语音会被丢掉
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if (_buffer.length > 0) {
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_emit(_buffer.takeBytes());
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}
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_buffer.clear();
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if (!_levelCtl.isClosed) _levelCtl.add(0);
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}
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Future<void> dispose() async {
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await stop();
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await _packets.close();
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await _levelCtl.close();
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await _recorder.dispose();
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}
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}
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