Flutter 无法边录音边播放音频

Question

我正在为那些听不清声音的人制作一个助听器应用程序，想法是麦克风让用户可以改变其频率，使用滑块或其他东西调整其他设置，然后扬声器使用经过处理的设置播放音频，我面临的问题是先录制音频然后播放，我如何让它直接从麦克风到扬声器播放音频，扬声器可以是手机/耳机。

我希望与麦克风一起播放音频。

import 'dart:async';
import 'dart:typed_data';
import 'package:flutter/material.dart';
import 'package:flutter_sound/flutter_sound.dart';
import 'package:permission_handler/permission_handler.dart';

class VoiceChanger extends StatefulWidget {
  @override
  _VoiceChangerState createState() => _VoiceChangerState();
}

class _VoiceChangerState extends State<VoiceChanger> {
  late final StreamController<Uint8List> _audioStreamController;

  FlutterSoundRecorder? _recorder;
  FlutterSoundPlayer? _player;
  bool isRecording = false;
  bool isPlayingBack = false;

  @override
  void initState() {
    super.initState();
    _recorder = FlutterSoundRecorder();
    _player = FlutterSoundPlayer();
    _audioStreamController = StreamController<Uint8List>();
    initAudio();
  }

  Future<void> initAudio() async {
    await _recorder!.openRecorder();
    await _player!.openPlayer();
    await _player!.setVolume(1.0);
  }

  Future<void> startRecording() async {
    if (await Permission.microphone.request().isGranted) {
      // Start recording to a stream
      await _recorder!.startRecorder(
        toStream: _audioStreamController.sink,
        codec: Codec.pcm16,
      );

      // Listen to the stream and play audio data in real-time
      _audioStreamController.stream.listen((data) async {
        // Ensure playback continues smoothly
        if (!isPlayingBack) {
          isPlayingBack = true;
          await _player!.startPlayer(
            fromDataBuffer: data,
            codec: Codec.pcm16,
            whenFinished: () {
              isPlayingBack = false; // Set playing flag to false when finished
            },
          );
        } else {
          // Feed the new audio data to the player without interruption
          await _player!.feedFromStream(data);
        }
      });

      setState(() {
        isRecording = true;
      });
    } else {
      print("Microphone permission is not granted");
    }
  }

  Future<void> stopRecording() async {
    await _recorder!.stopRecorder();
    setState(() {
      isRecording = false;
      isPlayingBack = false; // Stop playback
    });
  }

  @override
  void dispose() {
    _recorder?.closeRecorder();
    _player?.closePlayer();
    _audioStreamController.close(); // Ensure stream is closed
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Voice Changer'),
      ),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            ElevatedButton(
              onPressed: isRecording ? stopRecording : startRecording,
              child: Text(isRecording ? 'Stop Recording' : 'Start Recording'),
            ),
          ],
        ),
      ),
    );
  }
}

Answer 1

要实现录音时实时音频播放，请考虑以下方法：

1. 使用flutter_sound的feedFromStream方法： 您已经在使用此方法，但请确保在录音机提供音频数据后立即将音频数据提供给播放器。
2. 利用audioplayers包中的AudioTrack： 创建一个 AudioTrack 实例并将录制的音频数据传递给其 play 方法。
3. 探索其他包： dart_av：提供低级音频处理能力。 audiomix：允许混合音频流。
4. 修改flutter_sound包： 如果上述解决方案不起作用，请考虑修改flutter_sound包以启用实时播放。 这是包含 feedFromStream 的 startRecording 方法的更新版本： 飞镖

Future<void> startRecording() async {
  // ...
  _audioStreamController.stream.listen((data) async {
    if (_player!.isPlaying) {
      await _player!.feedFromStream(data);
    } else {
      await _player!.startPlayer(
        fromDataBuffer: data,
        codec: Codec.pcm16,
      );
    }
  });
  // ...
}