如何使用AVAssetWriter将h264流写入视频？

我想将 h.264 流从服务器传输到视频文件，但是当我使用assetwrite.finishwrite，XCode 报告

Video /var/mobile/Applications/DE4196F1-BB77-4B7D-8C20-7A5D6223C64D/Documents/test.mov cannot be saved to the saved photos album: Error Domain=NSOSStatusErrorDomain Code=-12847 "This movie format is not supported." UserInfo=0x5334830 {NSLocalizedDescription=This movie format is not supported.}"

下面是我的代码： data是h.264帧，只是一帧，可能是i帧或p。

(void)_encodeVideoFrame2:(NSData *) data time:(double)tm 
{
  CMBlockBufferRef videoBlockBuffer=NULL;
  CMFormatDescriptionRef videoFormat=NULL;
  CMSampleBufferRef videoSampleBuffer=NULL;
  CMItemCount numberOfSampleTimeEntries=1;
  CMItemCount numberOfSamples=1;
  CMVideoFormatDescriptionCreate(kCFAllocatorDefault, kCMVideoCodecType_H264, 320, 240, NULL, &videoFormat);
  OSStatus result;
  result=CMBlockBufferCreateWithMemoryBlock(kCFAllocatorDefault, NULL, data.length, kCFAllocatorDefault, NULL, 0, data.length, kCMBlockBufferAssureMemoryNowFlag, &videoBlockBuffer);
  result=CMBlockBufferReplaceDataBytes(data.bytes, videoBlockBuffer, 0, data.length);
  CMSampleTimingInfo videoSampleTimingInformation={CMTimeMake(tm*600, 600)};
  size_t sampleSizeArray[1];
  sampleSizeArray[0]=data.length;
  result=CMSampleBufferCreate(kCFAllocatorDefault, videoBlockBuffer, TRUE, NULL, NULL, videoFormat, numberOfSamples, numberOfSampleTimeEntries, &videoSampleTimingInformation, 1, sampleSizeArray, &videoSampleBuffer);
  result = CMSampleBufferMakeDataReady(videoSampleBuffer);
  [assetWriterInput appendSampleBuffer:videoSampleBuffer]; 
}

也许是CMSampleBufferCreate论证有误吗？谢谢。

为了复用已经压缩的 h264 缓冲区AVAssetWriter，你必须指定一个nilOutputSettings，与文档所述相反。

所以，而不是做

videoInput = [[AVAssetWriterInput alloc] 
    initWithMediaType:AVMediaTypeVideo outputSettings:@{
        AVVideoCodecKey: AVVideoCodecH264,
    }
    sourceFormatHint:myVideoFormat
];

你应该做

videoInput = [[AVAssetWriterInput alloc] 
    initWithMediaType:AVMediaTypeVideo
    outputSettings:nil
    sourceFormatHint:myVideoFormat
];

这将允许您传递视频或音频数据，而无需 AVAssetWriterInput 尝试为您编码/转码任何内容。