使用aurioTouch錄制音頻單元文件-AudioStreamBasicDescription配置問題？

Question

我已經開始使用aurioTouch學習音頻單元。 在學習了Audio Unit幾天后，我仍然感到有些失落，我想我會丟失一些非常明顯的東西。

完整的源代碼可以在以下位置查看： http : //pastebin.com/LXLYDEhy

還列出了部分來源

在我的performRender回調中，我將代碼更改為

static OSStatus performRender (void                         *inRefCon,
                           AudioUnitRenderActionFlags   *ioActionFlags,
                           const AudioTimeStamp         *inTimeStamp,
                           UInt32                       inBusNumber,
                           UInt32                       inNumberFrames,
                           AudioBufferList              *ioData) {

OSStatus err = noErr;
AudioController *audioController = (__bridge AudioController *)inRefCon;  
AudioBufferList bufferList;
bufferList.mNumberBuffers = 1;
bufferList.mBuffers[0].mData = NULL;
OSStatus status;
status = AudioUnitRender(cd.rioUnit,
                         ioActionFlags,
                         inTimeStamp,
                         inBusNumber,
                         inNumberFrames,
                         &bufferList); // bufferList.mBuffers[0].mData is null
status = ExtAudioFileWriteAsync(audioController.extAudioFileRef, bufferList.mNumberBuffers, &bufferList);
}

音頻單元的設置如下

- (AudioStreamBasicDescription)getAudioDescription {
AudioStreamBasicDescription audioDescription = {0};
audioDescription.mFormatID          = kAudioFormatLinearPCM;
audioDescription.mFormatFlags       = kAudioFormatFlagIsSignedInteger | kAudioFormatFlagIsPacked | kAudioFormatFlagsNativeEndian;
audioDescription.mChannelsPerFrame  = 1;
audioDescription.mBytesPerPacket    = sizeof(SInt16)*audioDescription.mChannelsPerFrame;
audioDescription.mFramesPerPacket   = 1;
audioDescription.mBytesPerFrame     = sizeof(SInt16)*audioDescription.mChannelsPerFrame;
audioDescription.mBitsPerChannel    = 8 * sizeof(SInt16);
audioDescription.mSampleRate        = 44100.0;
return audioDescription;
}


- (void)setupIOUnit
{
try {
    // Create a new instance of AURemoteIO

    AudioComponentDescription desc;
    desc.componentType = kAudioUnitType_Output;
    desc.componentSubType = kAudioUnitSubType_RemoteIO;
    desc.componentManufacturer = kAudioUnitManufacturer_Apple;
    desc.componentFlags = 0;
    desc.componentFlagsMask = 0;

    AudioComponent comp = AudioComponentFindNext(NULL, &desc);
    XThrowIfError(AudioComponentInstanceNew(comp, &_rioUnit), "couldn't create a new instance of AURemoteIO");

    //  Enable input and output on AURemoteIO
    //  Input is enabled on the input scope of the input element
    //  Output is enabled on the output scope of the output element

    UInt32 one = 1;
    XThrowIfError(AudioUnitSetProperty(_rioUnit, kAudioOutputUnitProperty_EnableIO, kAudioUnitScope_Input, 1, &one, sizeof(one)), "could not enable input on AURemoteIO");
    XThrowIfError(AudioUnitSetProperty(_rioUnit, kAudioOutputUnitProperty_EnableIO, kAudioUnitScope_Output, 0, &one, sizeof(one)), "could not enable output on AURemoteIO");

    // Explicitly set the input and output client formats
    // sample rate = 44100, num channels = 1, format = 32 bit floating point

    CAStreamBasicDescription ioFormat = CAStreamBasicDescription(44100, 1, CAStreamBasicDescription::kPCMFormatFloat32, false);
//        AudioStreamBasicDescription audioFormat = [self getAudioDescription];
    XThrowIfError(AudioUnitSetProperty(_rioUnit, kAudioUnitProperty_StreamFormat, kAudioUnitScope_Output, 1, &ioFormat, sizeof(ioFormat)), "couldn't set the input client format on AURemoteIO");
    XThrowIfError(AudioUnitSetProperty(_rioUnit, kAudioUnitProperty_StreamFormat, kAudioUnitScope_Input, 0, &ioFormat, sizeof(ioFormat)), "couldn't set the output client format on AURemoteIO");

    // Set the MaximumFramesPerSlice property. This property is used to describe to an audio unit the maximum number
    // of samples it will be asked to produce on any single given call to AudioUnitRender
    UInt32 maxFramesPerSlice = 4096;
    XThrowIfError(AudioUnitSetProperty(_rioUnit, kAudioUnitProperty_MaximumFramesPerSlice, kAudioUnitScope_Global, 0, &maxFramesPerSlice, sizeof(UInt32)), "couldn't set max frames per slice on AURemoteIO");

    // Get the property value back from AURemoteIO. We are going to use this value to allocate buffers accordingly
    UInt32 propSize = sizeof(UInt32);
    XThrowIfError(AudioUnitGetProperty(_rioUnit, kAudioUnitProperty_MaximumFramesPerSlice, kAudioUnitScope_Global, 0, &maxFramesPerSlice, &propSize), "couldn't get max frames per slice on AURemoteIO");

    _bufferManager = new BufferManager(maxFramesPerSlice);
    _dcRejectionFilter = new DCRejectionFilter;

    // We need references to certain data in the render callback
    // This simple struct is used to hold that information

    cd.rioUnit = _rioUnit;
    cd.bufferManager = _bufferManager;
    cd.dcRejectionFilter = _dcRejectionFilter;
    cd.muteAudio = &_muteAudio;
    cd.audioChainIsBeingReconstructed = &_audioChainIsBeingReconstructed;

    AURenderCallbackStruct renderCallback;
    renderCallback.inputProc = performRender;
    renderCallback.inputProcRefCon = self;

    XThrowIfError(AudioUnitSetProperty(_rioUnit, kAudioOutputUnitProperty_SetInputCallback, kAudioUnitScope_Global, 0, &renderCallback, sizeof(renderCallback)), "couldn't set render callback on AURemoteIO");


    // Initialize the AURemoteIO instance
    XThrowIfError(AudioUnitInitialize(_rioUnit), "couldn't initialize AURemoteIO instance");
}

catch (CAXException &e) {
    NSLog(@"Error returned from setupIOUnit: %d: %s", (int)e.mError, e.mOperation);
}
catch (...) {
    NSLog(@"Unknown error returned from setupIOUnit");
}

return;
}

完整的源代碼可以在以下位置查看： http : //pastebin.com/LXLYDEhy

Answer 1

乍一看，您的代碼通常看起來不錯，但是至少存在一個重要的問題：您沒有將要復制的數據分配給緩沖區的空間，而是將它們顯式設置為NULL 。 相反，您應該分配空間，然后使用AudioUnitRender復制到其中

示例代碼：

AudioBufferList *bufferList;
bufferList = (AudioBufferList *)malloc(sizeof(AudioBufferList) + sizeof(AudioBuffer));
bufferList->mNumberBuffers = 1;
bufferList->mBuffers[0].mNumberChannels = 1;
bufferList->mBuffers[0].mDataByteSize = 1024 * 4;
bufferList->mBuffers[0].mData = calloc(1024, 4);

（請注意，您可能需要調整分配大小以適合您的流類型，大小等-以上只是示例代碼，但它可以解決您的主要問題。