如何在AVAssetReaderTrackOutput中更改位颜色？

Question

我用来读取AVAssetReaderTrackOutput视频。

设置“kCVPixelBufferPixelFormatTypeKey” - “kCVPixelFormatType_32BGRA”工作！

但我需要一个16位视频。

如果设置设置值“kCVPixelFormatType_16 ....”不起作用。 [asset_reader_output copyNextSampleBuffer] - 总是nil =（

为什么会这样？

如何更改位颜色？

UPD： `代码：

[videoWriterInput requestMediaDataWhenReadyOnQueue:queueVideo usingBlock:^
{
    while([videoWriterInput isReadyForMoreMediaData])
    {
        CMSampleBufferRef sampleBuffer=[video_asset_reader_output copyNextSampleBuffer];
        if(sampleBuffer)
        {
            NSLog(@"write video");
            [videoWriterInput appendSampleBuffer:sampleBuffer];
            CFRelease(sampleBuffer);
        } else
        {
            [videoWriterInput markAsFinished];
            dispatch_release(queueVideo);
            videoFinished=YES;
            break;
        }
    }
}];

`

Answer 1

核心视频不支持所有像素格式。 BGRA保证可以工作。您必须执行自己的转换。你在使用什么缓冲区？

更新：要访问像素，请使用以下内容：

CVImageBufferRef pixelBuffer = CMSampleBufferGetImageBuffer(sampleBuffer);
CVPixelBufferLockBaseAddress(pixelBuffer, 0);

void* bufferAddress = CVPixelBufferGetBaseAddress(pixelBuffer);
size_t width = CVPixelBufferGetWidth(pixelBuffer);
size_t height = CVPixelBufferGetHeight(pixelBuffer);
size_t bytesPerRow = CVPixelBufferGetBytesPerRow(pixelBuffer);

// Read / modify the pixel data with bufferAddress, height & bytesPerRow
// For BGRA format, it's 4-byte per pixel in that order

CVPixelBufferUnlockBaseAddress(pixelBuffer, 0);