Question

我正在开发一个应用程序，其中我想混合多个声音来创建单个音频文件。我可以使用apple的MixerHost示例混合多个音频文件以生成单个音频，但是无法录制此音频以生成单个音频文件。我提到This链接来记录生成的音频。参考上面提到的链接，我能够生成音频文件，但它的静音（没有声音）。

Follwing是我的代码：

-(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, &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));


// 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];
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");}





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


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);

AudioMixerViewController* THIS = (__bridge AudioMixerViewController *)inRefCon;
OSStatus status;
status = AudioUnitRender(THIS->audioUnit,
                         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;

 }

我正在获取OSStatus（ExtAudioFileDispose）：0和OSStatus（ExtAudioFileDispose）： - 50

请帮帮我。谢谢！

使用音频单元录制iPhone输出声音

0 个答案: