谁能帮我通过音频单元录制 iPhone 输出的声音答案

【问题标题】：Can anybody help me in recording iPhone output sound through Audio Unit谁能帮我通过音频单元录制 iPhone 输出的声音
【发布时间】：2012-01-26 18:32:14
【问题描述】：

这是我的代码：我使用此代码通过 Audio Unit 录制 iPhone 输出音频然后将输出保存在 output.caf 但 output.caf 文件为空任何人都知道我该怎么做？输出音频文件为空

这是初始化音频单元

-(void) initializaeOutputUnit
{
    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, &audioUnit);

    // Enable IO for recording
    UInt32 flag = 1;
    status = AudioUnitSetProperty(audioUnit, 
                                  kAudioOutputUnitProperty_EnableIO, 
                                  kAudioUnitScope_Input, 
                                  kInputBus,
                                  &flag, 
                                  sizeof(flag));

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

    // Describe format
    AudioStreamBasicDescription audioFormat={0};
    audioFormat.mSampleRate         = 44100.00;
    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(audioUnit, 
                                  kAudioUnitProperty_StreamFormat, 
                                  kAudioUnitScope_Output, 
                                  kInputBus, 
                                  &audioFormat, 
                                  sizeof(audioFormat));
    status = AudioUnitSetProperty(audioUnit, 
                                  kAudioUnitProperty_StreamFormat, 
                                  kAudioUnitScope_Input, 
                                  kOutputBus, 
                                  &audioFormat, 
                                  sizeof(audioFormat));


    // Set input callback
    AURenderCallbackStruct callbackStruct;
    callbackStruct.inputProc = recordingCallback;
    callbackStruct.inputProcRefCon = self;
    status = AudioUnitSetProperty(audioUnit, 
                                  kAudioOutputUnitProperty_SetInputCallback, 
                                  kAudioUnitScope_Global, 
                                  kInputBus, 
                                  &callbackStruct, 
                                  sizeof(callbackStruct));

    // Set output callback
    callbackStruct.inputProc = playbackCallback;
    callbackStruct.inputProcRefCon = self;
    status = AudioUnitSetProperty(audioUnit, 
                                  kAudioUnitProperty_SetRenderCallback, 
                                  kAudioUnitScope_Global, 
                                  kOutputBus,
                                  &callbackStruct, 
                                  sizeof(callbackStruct));

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


    AudioUnitInitialize(audioUnit);
    AudioOutputUnitStart(audioUnit);


    // On initialise le fichier audio
    NSArray  *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *documentsDirectory = [paths objectAtIndex:0];
    NSString *destinationFilePath = [[[NSString alloc] initWithFormat: @"%@/output.caf", documentsDirectory] autorelease];
    NSLog(@">>> %@", destinationFilePath);
    CFURLRef destinationURL = CFURLCreateWithFileSystemPath(kCFAllocatorDefault, (CFStringRef)destinationFilePath, kCFURLPOSIXPathStyle, false);

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

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

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

   }

录音回调

static OSStatus recordingCallback       (void *                         inRefCon,
                                         AudioUnitRenderActionFlags *      ioActionFlags,
                                         const AudioTimeStamp *            inTimeStamp,
                                         UInt32                            inBusNumber,
                                         UInt32                            inNumberFrames,
                                         AudioBufferList *                 ioData) {
    NSLog(@"callback");
   if (*ioActionFlags == kAudioUnitRenderAction_PostRender&&inBusNumber==0) 
   {
        AudioBufferList *bufferList; // <- Fill this up with buffers (you will want to malloc it, as it's a dynamic-length list)

        EffectState *effectState = (EffectState *)inRefCon;
       AudioUnit rioUnit =[(MixerHostAudio*)inRefCon getAudioUnit];

        OSStatus status;
        NSLog(@"de5eal el call back ");
        // BELOW I GET THE ERROR
        status = AudioUnitRender( rioUnit,     
                                 ioActionFlags, 
                                 inTimeStamp, 
                                 inBusNumber, 
                                 inNumberFrames, 
                                 bufferList);

        if (noErr != status) { NSLog(@"AudioUnitRender error"); return noErr;}

        // Now, we have the samples we just read sitting in buffers in bufferList
        ExtAudioFileWriteAsync(effectState->audioFileRef, inNumberFrames, bufferList);

    }
    return noErr;     
}




// then stop Recording 
- (void) stopRecord
{

    AudioOutputUnitStop(audioUnit);
    AudioUnitUninitialize(audioUnit);
}

【问题讨论】：

仅仅说“这是我的代码”然后发布整个应用程序是不够的。这不算是一个问题。
说清楚并解释整个场景。
从ExtAudioFileWriteAsync返回有错误吗？
不，ExAudioFileWriteAsync 没有错误，但是当我删除 status = AudioUnitRender(rioUnit, ioActionFlags, inTimeStamp, inBusNumber, inNumberFrames, bufferList);并用 ioData 替换缓冲区列表并删除录制回调 ExtAudioFileWriteAsync(effectState->audioFileRef, inNumberFrames, ioData) 中的 if 语句；输出文件空间为 659KB 但无法正常工作

标签： iphone ios5 core-audio audiounit

【解决方案1】：

在 initializaeOutputUnit 您只创建了音频文件：

OSStatus setupErr = ExtAudioFileCreateWithURL(destinationURL, kAudioFileWAVEType, &audioFormat, NULL, kAudioFileFlags_EraseFile, &effectState.audioFileRef);

通过传递 0（帧）和 NULL（音频缓冲区）仅用于初始化内部缓冲区：

setupErr =  ExtAudioFileWriteAsync(effectState.audioFileRef, 0, NULL);

这就是 recordingCallback 中出了什么问题：

1) ioActionFlags 始终为 0，inBusNumber 始终为 1，因为这就是您设置回调的方式 (kInputBus = 1)：

if (*ioActionFlags == kAudioUnitRenderAction_PostRender&&inBusNumber==0)

所以只需删除 if 语句。

2) 从 AudioUnitRender 您将收到 -50 错误，它在 CoreAudioTypes.h 中定义为 kAudio_ParamError 错误。发生这种情况的原因是 bufferList 未定义且为 NULL！

 OSStatus status; 
 status = AudioUnitRender(THIS->mAudioUnit,     
                          ioActionFlags, 
                          inTimeStamp, 
                          kInputBus, 
                          inNumberFrames, 
                          &bufferList);

 if (noErr != status) {
      printf("AudioUnitRender error: %ld", status);   
      return noErr; 
 }

您只需要定义一个有效的 AudioBuffer 并将其传递给 AudioUnitRender，这是我的工作 RenderCallback：

  static OSStatus recordingCallback       (void *                      inRefCon,
                                           AudioUnitRenderActionFlags *      ioActionFlags,
                                           const AudioTimeStamp *            inTimeStamp,
                                           UInt32                            inBusNumber,
                                           UInt32                            inNumberFrames,
                                           AudioBufferList *                 ioData)  {
      double timeInSeconds = inTimeStamp->mSampleTime / kSampleRate;
      printf("\n%fs inBusNumber: %lu inNumberFrames: %lu ", timeInSeconds, inBusNumber, inNumberFrames);
      //printAudioUnitRenderActionFlags(ioActionFlags);

      AudioBufferList bufferList;

      SInt16 samples[inNumberFrames]; // A large enough size to not have to worry about buffer overrun
      memset (&samples, 0, sizeof (samples));

      bufferList.mNumberBuffers = 1;
      bufferList.mBuffers[0].mData = samples;
      bufferList.mBuffers[0].mNumberChannels = 1;
      bufferList.mBuffers[0].mDataByteSize = inNumberFrames*sizeof(SInt16);

      ViewController* THIS = THIS = (__bridge ViewController *)inRefCon;

      OSStatus status;
      status = AudioUnitRender(THIS->mAudioUnit,     
                               ioActionFlags, 
                               inTimeStamp, 
                               kInputBus, 
                               inNumberFrames, 
                               &bufferList);

      if (noErr != status) {

          printf("AudioUnitRender error: %ld", status); 
          return noErr;
      }

      // Now, we have the samples we just read sitting in buffers in bufferList
      ExtAudioFileWriteAsync(THIS->mAudioFileRef, inNumberFrames, &bufferList);

      return noErr;      
 }

在 stopRecord 中，您应该使用 ExtAudioFileDispose 关闭音频文件：

  - (void)stopRecording:(NSTimer*)theTimer {
      printf("\nstopRecording\n");
      AudioOutputUnitStop(mAudioUnit);
      AudioUnitUninitialize(mAudioUnit);

      OSStatus status = ExtAudioFileDispose(mAudioFileRef);
      printf("OSStatus(ExtAudioFileDispose): %ld\n", status); 
 }

完整源码：http://pastebin.com/92Fyjaye

【讨论】：

【解决方案2】：

RemoteIO 音频单元不记录音频输出，只记录来自麦克风的输入。输出未连接到麦克风输入。

如果您使用 RemoteIO 播放音频，您可以将副本复制到与播放音频的输出回调相同的缓冲区到文件写入器。但这仅适用于您通过 RemoteIO 播放的原始音频内容。

【讨论】：

我使用有关音频单元的链接编写我的代码 [博客] (atastypixel.com/blog/using-remoteio-audio-unit) [问题] (stackoverflow.com/questions/7118429/…) 为什么我使用远程 I/o 来记录音频输出
RemoteIO 不记录音频输出。请阅读 Apple 的官方音频单元文档。
那么您有任何文档可以帮助我记录 iPhone 音频输出吗？？？
我有同样的问题，我想像开始录音一样录制内部 iphone 声音，然后在 iphone 应用程序中播放一些声音，停止录制后必须录制声音。我该怎么做？跨度>
@Khoool ：一般来说，你不能。