这是我的代码： 我使用此代码通过使用音频单元录制iPhone输出音频 然后将输出保存在output.caf中，但output.caf文件为空 任何人都知道我该怎么办？ 输出音频文件为空
这是音频单元的初始化
-(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");
}
录音回电
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);
}
答案 0 :(得分：14)
在 initializaeOutputUnit 中，您只创建了音频文件：
OSStatus setupErr = ExtAudioFileCreateWithURL(destinationURL, kAudioFileWAVEType, &audioFormat, NULL, kAudioFileFlags_EraseFile, &effectState.audioFileRef);
传递 0 （帧）和 NULL （audiobuffer）仅适用于init内部缓冲区：
setupErr = ExtAudioFileWriteAsync(effectState.audioFileRef, 0, NULL);
这就是 recordingCallback ：
中出现的问题1）ioActionFlags始终为0且inBusNumber始终为1，因为这就是你如何设置回调（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。这种情况发生在bufferList没有定义和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); }
答案 1 :(得分：3)
RemoteIO音频单元不录制音频输出，仅录制麦克风输入。输出未连接到麦克风输入。
如果使用RemoteIO播放音频，则可以将复制相同的缓冲区复制到输出回调中，以便将音频播放到文件编写器。但这仅适用于您通过RemoteIO播放的原始音频内容。