ios - 远程 IO 音频单元未从扬声器或远程流中捕获音频

Question

我正在使用以下代码录制音频并将其写入文件

- (void) initializeOutputUnit
{
    OSStatus status;

    // Describe audio component
    AudioComponentDescription desc;
    desc.componentType = kAudioUnitType_Output;
    desc.componentSubType = kAudioUnitSubType_RemoteIO;
    desc.componentFlags = 0;
    desc.componentFlagsMask = 0;
    desc.componentManufacturer = kAudioUnitManufacturer_Apple;

    // Get component
    AudioComponent inputComponent = AudioComponentFindNext(NULL, &desc);

    // Get audio units
    status = AudioComponentInstanceNew(inputComponent, &mAudioUnit);

    // Enable IO for recording
    UInt32 flag = 1;

    //bhoomi
    status = AudioUnitSetProperty(mAudioUnit,
                                  kAudioOutputUnitProperty_EnableIO,
                                  kAudioUnitScope_Input,
                                  kInputBus,
                                  &flag,
                                  sizeof(flag));




    // Enable IO for playback
    status = AudioUnitSetProperty(mAudioUnit,
                                  kAudioOutputUnitProperty_EnableIO,
                                  kAudioUnitScope_Output,
                                  kOutputBus,
                                  &flag,
                                  sizeof(flag));

    // Describe format
    AudioStreamBasicDescription audioFormat={0};
    audioFormat.mSampleRate         = kSampleRate;
    audioFormat.mFormatID           = kAudioFormatLinearPCM;
    audioFormat.mFormatFlags        = kAudioFormatFlagIsSignedInteger | kAudioFormatFlagIsPacked;
    audioFormat.mFramesPerPacket    = 1;
    audioFormat.mChannelsPerFrame   = 1;
    audioFormat.mBitsPerChannel     = 16;
    audioFormat.mBytesPerPacket     = 2;
    audioFormat.mBytesPerFrame      = 2;

    // Apply format
    status = AudioUnitSetProperty(mAudioUnit,
                                  kAudioUnitProperty_StreamFormat,
                                  kAudioUnitScope_Output,
                                  kInputBus,
                                  &audioFormat,
                                  sizeof(audioFormat));
    status = AudioUnitSetProperty(mAudioUnit,
                                  kAudioUnitProperty_StreamFormat,
                                  kAudioUnitScope_Input,
                                  kOutputBus,
                                  &audioFormat,
                                  sizeof(audioFormat));


    // Set input callback
    AURenderCallbackStruct callbackStruct;
    callbackStruct.inputProc = recordingCallback;
    callbackStruct.inputProcRefCon = (__bridge void *)self;

    status = AudioUnitSetProperty(mAudioUnit,
                                  kAudioOutputUnitProperty_SetInputCallback,
                                  kAudioUnitScope_Global,
                                  kInputBus,
                                  &callbackStruct,
                                  sizeof(callbackStruct));


    // Disable buffer allocation for the recorder (optional - do this if we want to pass in our own)
    flag = 0;
    status = AudioUnitSetProperty(mAudioUnit,
                                  kAudioUnitProperty_ShouldAllocateBuffer,
                                  kAudioUnitScope_Output,
                                  kInputBus,
                                  &flag,
                                  sizeof(flag));

    // On initialise le fichier audio
    NSArray  *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *documentsDirectory = [paths objectAtIndex:0];
    NSString *destinationFilePath = [[NSString alloc] initWithFormat: @"%@/output.caf", documentsDirectory];
    NSLog(@">>> %@\n", destinationFilePath);

    CFURLRef destinationURL = CFURLCreateWithFileSystemPath(kCFAllocatorDefault, (__bridge CFStringRef)destinationFilePath, kCFURLPOSIXPathStyle, false);

    OSStatus setupErr = ExtAudioFileCreateWithURL(destinationURL, kAudioFileCAFType, &audioFormat, NULL, kAudioFileFlags_EraseFile, &mAudioFileRef);
    CFRelease(destinationURL);
    NSAssert(setupErr == noErr, @"Couldn't create file for writing");

    setupErr = ExtAudioFileSetProperty(mAudioFileRef, kExtAudioFileProperty_ClientDataFormat, sizeof(AudioStreamBasicDescription), &audioFormat);
    NSAssert(setupErr == noErr, @"Couldn't create file for format");

    setupErr =  ExtAudioFileWriteAsync(mAudioFileRef, 0, NULL);
    NSAssert(setupErr == noErr, @"Couldn't initialize write buffers for audio file");

    CheckError(AudioUnitInitialize(mAudioUnit), "AudioUnitInitialize");
    CheckError(AudioOutputUnitStart(mAudioUnit), "AudioOutputUnitStart");

  //  [NSTimer scheduledTimerWithTimeInterval:5 target:self selector:@selector(stopRecording:) userInfo:nil repeats:NO];


}

在我的应用程序中，我有使用 webRTC 的视频通话功能。上面的代码与麦克风音频一起工作正常，麦克风音频被正确录制，但我无法录制扬声器声音（远程音频流）。是否可以在同一个文件中同时录制声音（麦克风和扬声器）？如果是，那么如何修改代码以便它也可以录制来自内部 iphone 扬声器的声音。

标签： ioscore-audioaudio-recordingremoteio