如何在 iOS (Flutter) 上调用 Agora RTC SDK 时获取麦克风输入流？

如何解决如何在 iOS (Flutter) 上调用 Agora RTC SDK 时获取麦克风输入流？

我想做什么

嗨。我正在使用 Google Speech-to-text 制作语音通话应用程序。为了实现这一点，我需要不断地将麦克风输入流传送到谷歌语音到文本。

问题

不幸的是，Agora RTC SDK 和获取麦克风输入流在 iOS 上似乎存在冲突。他们在 Android 设备上工作。

环境

iPhone X (14.4.2)

❯ flutter doctor
Doctor summary (to see all details,run flutter doctor -v):
[✓] Flutter (Channel stable,2.2.0,on macOS 11.2.3 20D91 darwin-x64,locale en-JP)
[✓] Android toolchain - develop for Android devices (Android SDK version 30.0.3)
[✓] Xcode - develop for iOS and macOS
[✓] Chrome - develop for the web
[✓] Android Studio (version 4.1)
[✓] VS Code (version 1.56.2)
[✓] Connected device (3 available)

• No issues found!

我关注了这两个项目。要获得麦克风输入流， https://github.com/CasperPas/flutter-sound-stream/tree/master/example 并初始化 Agora RTC， https://github.com/Meherdeep/Agora-Voice-Bot

代码

main.dart（放置 Agora APP ID 和 Token）。此示例未使用 RtcEngineEventHandler，但我只想在 RtcEngineEventHandler 的 joinChannelSuccess 回调中启动语音转文本。

import 'dart:async';
import 'dart:typed_data';
import 'package:flutter/material.dart';
import 'package:sound_stream/sound_stream.dart';
import 'package:agora_rtc_engine/agora_rtc_engine.dart';
import 'package:samplestream/utils/appID.dart';

void main() {
  runApp(MyApp());
}

class MyApp extends StatefulWidget {
  @override
  _MyAppState createState() => _MyAppState();
}

class _MyAppState extends State<MyApp> {
  RecorderStream _recorder = RecorderStream();
  PlayerStream _player = PlayerStream();

  List<Uint8List> _micChunks = [];
  bool _isRecording = false;
  bool _isPlaying = false;

  StreamSubscription _recorderStatus;
  StreamSubscription _playerStatus;
  StreamSubscription _audioStream;

  @override
  void initState() {
    super.initState();
    initPlugin();
    initialize();
  }

  @override
  void dispose() {
    _recorderStatus?.cancel();
    _playerStatus?.cancel();
    _audioStream?.cancel();
    super.dispose();
    // destroy sdk
    AgoraRtcEngine.leaveChannel();
    AgoraRtcEngine.destroy();
    super.dispose();
  }

  // Platform messages are asynchronous,so we initialize in an async method.
  Future<void> initPlugin() async {
    _recorderStatus = _recorder.status.listen((status) {
      if (mounted)
        setState(() {
          _isRecording = status == SoundStreamStatus.Playing;
        });
    });

    _audioStream = _recorder.audioStream.listen((data) {
      print(data);
      if (_isPlaying) {
        _player.writeChunk(data);
      } else {
        _micChunks.add(data);
      }
    });

    _playerStatus = _player.status.listen((status) {
      if (mounted)
        setState(() {
          _isPlaying = status == SoundStreamStatus.Playing;
        });
    });

    await Future.wait([
      _recorder.initialize(),_player.initialize(),]);
  }

  void _play() async {
    await _player.start();

    if (_micChunks.isNotEmpty) {
      for (var chunk in _micChunks) {
        await _player.writeChunk(chunk);
      }
      _micChunks.clear();
    }
  }

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(
          title: const Text('Plugin example app'),),body: Row(
          mainAxisAlignment: MainAxisAlignment.spaceAround,children: [
            IconButton(
              iconSize: 96.0,icon: Icon(_isRecording ? Icons.mic_off : Icons.mic),onPressed: _isRecording ? _recorder.stop : _recorder.start,IconButton(
              iconSize: 96.0,icon: Icon(_isPlaying ? Icons.pause : Icons.play_arrow),onPressed: _isPlaying ? _player.stop : _play,],);
  }

  Future<void> initialize() async {
    const String appID = 'putYourAgoraRtcAppID';

    await AgoraRtcEngine.setChannelProfile(ChannelProfile.LiveBroadcasting);
    await AgoraRtcEngine.create(appID);
    // await AgoraRtcEngine.enableWebSdkInteroperability(true);
    await AgoraRtcEngine.joinChannel('putYourAgoraRtcToken','test',null,0);
  }
}

pubspec.yaml

name: samplestream
description: Demonstrates how to use the sound_stream plugin.
publish_to: 'none'

environment:
  sdk: ">=2.7.0 <3.0.0"

dependencies:
  flutter:
    sdk: flutter

  sound_stream: ^0.2.0
  cupertino_icons: ^0.1.3
  web_socket_channel: ^1.1.0
  agora_rtc_engine: ^1.0.12

dev_dependencies:
  flutter_test:
    sdk: flutter

flutter:
  uses-material-design: true

日志

Performing hot restart...                                               
Restarted application in 610ms.
plugin handleMethodCall: setChannelProfile,argus: {
    profile = 1;
}
plugin handleMethodCall: create,argus: {
    appId = b7...c;
}
plugin handleMethodCall: joinChannel,argus: {
    channelId = test;
    info = "<null>";
    token = "006b7...hg";
    uid = 0;
}
[avae]            AVAEInternal.h:76    required condition is false: [AVAudioIONodeImpl.mm:1158:SetOutputFormat: (format.sampleRate == hwFormat.sampleRate)]
*** Terminating app due to uncaught exception 'com.apple.coreaudio.avfaudio',reason: 'required condition is false: format.sampleRate == hwFormat.sampleRate'
*** First throw call stack:
(0x194d319d8 0x1a90b4b54 0x194c4050c 0x1a4c97984 0x1a4d41998 0x1a4cf5d24 0x1a4cddb3c 0x1a4d5ade8 0x1a4d3c1e4 0x1015d3d20 0x1015d4644 0x1015d11d0 0x1015d1920 0x101d2ad60 0x101a3c07c 0x101d45370 0x101cdf4d4 0x101ce1cfc 0x194cb23e0 0x194cb1fe4 0x194cb14c4 0x194cab850 0x194caaba0 0x1aba10598 0x19759c2f4 0x1975a1874 0x1005de114 0x194989568)
libc++abi.dylib: terminating with uncaught exception of type NSException
* thread #1,queue = 'com.apple.main-thread',stop reason = signal SIGABRT
    frame #0: 0x00000001c0bf284c libsystem_kernel.dylib`__pthread_kill + 8
libsystem_kernel.dylib`__pthread_kill:
->  0x1c0bf284c <+8>:  b.lo   0x1c0bf2868               ; <+36>
    0x1c0bf2850 <+12>: stp    x29,x30,[sp,#-0x10]!
    0x1c0bf2854 <+16>: mov    x29,sp
    0x1c0bf2858 <+20>: bl     0x1c0bcff5c               ; cerror_nocancel
Target 0: (Runner) stopped.
Lost connection to device.

感谢阅读！