CMSampleBufferSetDataBufferFromAudioBufferList 返回错误 12731

Question

我正在尝试捕获应用程序声音并将其传递给 AVAssetWriter 作为输入。
我正在设置音频单元的回调以获取 AudioBufferList。
问题始于将 AudioBufferList 转换为 CMSampleBufferRef。
它总是返回错误 -12731，这表明缺少所需的参数，

谢谢
Karol

-(OSStatus) recordingCallbackWithRef:(void*)inRefCon
                            flags:(AudioUnitRenderActionFlags*)flags
                        timeStamp:(const AudioTimeStamp*)timeStamp
                        busNumber:(UInt32)busNumber
                     framesNumber:(UInt32)numberOfFrames
                             data:(AudioBufferList*)data
{

AudioBufferList bufferList;
bufferList.mNumberBuffers = 1;
bufferList.mBuffers[0].mData = NULL;

OSStatus status;

status = AudioUnitRender(audioUnit,
                         flags,
                         timeStamp,
                         busNumber,
                         numberOfFrames,
                         &bufferList);
[self checkOSStatus:status];

AudioStreamBasicDescription audioFormat;
// Describe format
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;

CMSampleBufferRef buff = NULL;
CMFormatDescriptionRef format = NULL;
CMSampleTimingInfo timing = { CMTimeMake(1, 44100), kCMTimeZero, kCMTimeInvalid };

status = CMAudioFormatDescriptionCreate(kCFAllocatorDefault, &audioFormat, 0, NULL, 0, NULL, NULL, &format);
[self checkOSStatus:status];

status = CMSampleBufferCreate(kCFAllocatorDefault,NULL,false,NULL,NULL,format,1, 1, &timing, 0, NULL, &buff);
[self checkOSStatus:status];

status = CMSampleBufferSetDataBufferFromAudioBufferList(buff, 
                                                        kCFAllocatorDefault, 
                                                        kCFAllocatorDefault, 
                                                        0, 
                                                        &bufferList);

[self checkOSStatus:status]; //Status here is 12731

//Do something with the buffer

return noErr;
}

编辑：
我检查了 bufferList.mBuffers[0].mData 并且它不为空，所以这可能不是问题。

Answer 1

因为网上到处都有类似的问题没有答案。
我设法解决了这个问题并且录音完全正常。
我的问题是传递给的参数错误CMSampleBufferCreate。
numSamples 而不是 1 应等于 numberOfFrames。

所以最后的调用是：

CMSampleBufferCreate(kCFAllocatorDefault,NULL,false,NULL,NULL,format,
                    (CMItemCount)numberOfFrames, 1, &timing, 0, NULL, &buff);