如何写一个AVAssetWriter我的自定义float / shorts数组？

Question

所以我使用AVAssetReader得到CMSampleBufferRef，然后我从CMBlockBufferRef数据中获取了样本值。

然后，我使用自定义过滤器更改了此示例。

现在我有一个Shorts数组，我想用AVAssetWriter写回文件。

我的问题是如何创建一个CMSampleBufferRef和一个CMBlockBufferRef来发送给AVAssetWriter？

Answer 1

看看这个apple developer page。

修改 根据您的意见，要直接从short数组创建samplebuffer，您应该使用Core Media Framework组件，即CMSampleBufferCreate

1. 将short数组中的样本数据转换为AudioBufferList
2. 将AudioBufferList转换为CMSampleBuffer。

例如：

OSStatus status = noErr;
CMItemCount framesToProcess = 8192;
unsigned long sizeInBytes = framesToProcess * sizeof(SInt16);

// Init ABL from sample array
AudioBufferList *myAudioBufferList; // contains converted
myAudioBufferList = static_cast<AudioBufferList *>(calloc(1, offsetof(AudioBufferList, mBuffers) + (sizeof(AudioBuffer))));
myAudioBufferList->mNumberBuffers = 1;
myAudioBufferList->mBuffers[0].mNumberChannels = 1;
myAudioBufferList->mBuffers[0].mData = JoãoSamplesArrayPointer;
myAudioBufferList->mBuffers[0].mDataByteSize = (UInt32)sizeInBytes;

// sampleBuffer in (from the assetreader) you already have this
CMSampleBufferRef sampleBufferIn = [self.assetReaderAudioOutput copyNextSampleBuffer];

CMAudioFormatDescriptionRef format = CMSampleBufferGetFormatDescription(sampleBufferIn);
const AudioStreamBasicDescription *assetReaderOutputASBD = CMAudioFormatDescriptionGetStreamBasicDescription(format);

// setup output samplebuffer
CMSampleBufferRef sampleBufferOut = NULL;
CMSampleTimingInfo timing = { CMTimeMake(1, sampleRate), kCMTimeZero, kCMTimeInvalid };

// create description
status = CMAudioFormatDescriptionCreate(kCFAllocatorDefault, assetReaderOutputASBD, 0, NULL, 0, NULL, NULL, &format);

// create buffer
CMSampleBufferCreate( kCFAllocatorDefault, NULL, false, NULL, NULL, format, framesToProcess, 1, &timing, 0, NULL, &sampleBufferOut);

// put data into buffer from ABL (audio buffer list)
status = CMSampleBufferSetDataBufferFromAudioBufferList( sampleBufferOut, kCFAllocatorDefault,  kCFAllocatorDefault, 0, myAudioBufferList );

// write to assetwriter audioinput
BOOL success = [self.assetWriterAudioInput appendSampleBuffer:sampleBufferOut];
CFRelease(sampleBufferOut);