AudioUnitInitialize 在初始化 AudioComponentInstance 时抛出错误

Posted 2023-02-25

【中文标题】AudioUnitInitialize 在初始化 AudioComponentInstance 时抛出错误

【英文标题】：AudioUnitInitialize throws error while initializing AudioComponentInstance

【发布时间】：2012-05-15 11:24:02

【问题描述】：

我正在使用下面的代码来初始化我的音频组件。

-(void) startListeningWithCoreAudio

     NSError *error = nil;

     [[AVAudiosession sharedInstance] setCategory: AVAudioSessionCategoryPlayAndRecord error:&error];
     if (error) 
          NSLog(@"error setting up audio session: %@", [error localizedDescription]);

     [[AVAudioSession sharedInstance] setDelegate:self];

     OSStatus status = AudioSessionSetActive(YES);
     checkStatus(status);

          // Find the apple mic
    AudioComponentDescription desc;
    desc.componentType = kAudioUnitType_Output;
    desc.componentSubType = kAudioUnitSubType_VoiceProcessingIO;
    desc.componentFlags = 0;
    desc.componentFlagsMask = 0;
    desc.componentManufacturer = kAudioUnitManufacturer_Apple;

    AudioComponent inputComponent = AudioComponentFindNext( NULL, &desc );
    status = AudioComponentInstanceNew( inputComponent, &kAudioUnit );
    checkStatus( status );

          // enable mic output as our input
    UInt32 flag = 1;
    status = AudioUnitSetProperty( kAudioUnit, kAudioOutputUnitProperty_EnableIO, kAudioUnitScope_Input, kInputBus, &flag, sizeof(flag) );
    checkStatus(status);


          // Define mic output audio format
    AudioStreamBasicDescription audioFormat;
    audioFormat.mSampleRate         = 16000.0;
    audioFormat.mFormatID           = kAudioFormatLinearPCM;
    audioFormat.mFormatFlags        = kAudioFormatFlagIsSignedInteger | kAudioFormatFlagIsPacked;
    audioFormat.mFramesPerPacket    = 1;
    audioFormat.mChannelsPerFrame   = 1;
    audioFormat.mBitsPerChannel     = 16;
    audioFormat.mBytesPerPacket     = 2;
    audioFormat.mBytesPerFrame      = 2;

    status = AudioUnitSetProperty( kAudioUnit, kAudioUnitProperty_StreamFormat, kAudioUnitScope_Output, kInputBus, &audioFormat, sizeof(audioFormat) );
    checkStatus(status);

          // Define our callback methods
    AURenderCallbackStruct callbackStruct;
    callbackStruct.inputProc = recordingCallback;
    callbackStruct.inputProcRefCon = self;
    status = AudioUnitSetProperty( kAudioUnit, kAudioOutputUnitProperty_SetInputCallback, kAudioUnitScope_Global, kInputBus, &callbackStruct, sizeof(callbackStruct) );
    checkStatus(status);

          // By pass voice processing
     UInt32 audiobypassProcessing = [[NSUserDefaults standardUserDefaults] boolForKey:VOICE_BY_PASS_PROCESSING];
     status = AudioUnitSetProperty(kAudioUnit, kAUVoiceIOProperty_BypassVoiceProcessing, 
                                   kAudioUnitScope_Global, kInputBus, &audiobypassProcessing, sizeof(audiobypassProcessing));
     checkStatus(status);

          // Automatic Gain Control
     UInt32 audioAGC = [[NSUserDefaults standardUserDefaults]boolForKey:VOICE_AGC];
     status = AudioUnitSetProperty(kAudioUnit, kAUVoiceIOProperty_VoiceProcessingEnableAGC, 
                                   kAudioUnitScope_Global, kInputBus, &audioAGC, sizeof(audioAGC));
     checkStatus(status);

          //Non Audio Voice Ducking
     UInt32 audioDucking = [[NSUserDefaults standardUserDefaults]boolForKey:VOICE_DUCKING];
     status = AudioUnitSetProperty(kAudioUnit, kAUVoiceIOProperty_DuckNonVoiceAudio, 
                                   kAudioUnitScope_Global, kInputBus, &audioDucking, sizeof(audioDucking));
     checkStatus(status);

          //Audio Quality
     UInt32 quality = [[NSUserDefaults standardUserDefaults]integerForKey:VOICE_QUALITY];
     status = AudioUnitSetProperty(kAudioUnit, kAUVoiceIOProperty_VoiceProcessingQuality, 
                                   kAudioUnitScope_Global, kInputBus, &quality, sizeof(quality));
     checkStatus(status);

     status = AudioUnitInitialize(kAudioUnit);
     checkStatus(status);

    status = AudioOutputUnitStart( kAudioUnit );
    checkStatus(status);

    UInt32 audioRoute = (UInt32)kAudioSessionOverrideAudioRoute_Speaker;
    status = AudioSessionSetProperty(kAudioSessionProperty_OverrideAudioRoute, sizeof (audioRoute), &audioRoute);
    checkStatus(status);     



-(void) stopListeningWithCoreAudio
 
    OSStatus     status = AudioUnitUninitialize( kAudioUnit );
     checkStatus(status);

     status = AudioOutputUnitStop( kAudioUnit );
    checkStatus( status );

//     if(kAudioUnit)
//     
//          status = AudioComponentInstanceDispose(kAudioUnit);
//          checkStatus(status);
//          kAudioUnit = nil;
//     

    status = AudioSessionSetActive(NO);
     checkStatus(status);

     NSError *error = nil;
    [[AVAudioSession sharedInstance] setCategory: AVAudioSessionCategorySoloAmbient error:&error];
    if (error)
          NSLog(@"error setting up audio session: %@", [error localizedDescription]);

它第一次运行良好。我的意思是startListeningWithCoreAudio 被按钮按下事件调用。它可以很好地录制/处理音频。在其他事件中，我打电话给stopListeningWithCoreAudio 来停止录制/处理音频。

当我再次尝试调用函数startListeningWithCoreAudio 时，问题就来了。它为两个函数抛出错误。 AudioUnitInitialize 和 AudioOutputUnitStart 从 startListeningWithCoreAudio 调用。

谁能帮我看看有什么问题？

【参考方案1】：

我找到了解决方案。 如果我们背靠背调用下面的函数，就会产生问题。

extern OSStatus AudioUnitUninitialize(AudioUnit inUnit)                     
extern OSStatus AudioComponentInstanceDispose(AudioComponentInstance inInstance)

所以，我通过以下方式在主线程上调用了 dispose 方法。

[self performSelectorOnMainThread:@selector(disposeCoreAudio) withObject:nil waitUntilDone:NO];

-(void) disposeCoreAudio

     OSStatus status = AudioComponentInstanceDispose(kAudioUnit);
     kAudioUnit = nil;

它解决了这个问题。因此，正确的顺序是停止录制，取消初始化录制器，然后在主线程上释放录制器。

【参考方案2】：

一个可能的问题是您的代码试图在停止之前取消初始化正在运行的音频单元。

【讨论】：

感谢您的回答。为此+1。实际原因是音频会话。我在应用程序处于活动状态时设置会话，并在应用程序进入后台时删除会话。之后没有音频单元的初始化。