Hey guys, tried to follow the super confusing doc on this, but no luck yet.
I have code that uses AVAssetReader and AVAssetReaderTrackOutput to directly pull frames from a video, but the colors are wrong for HDR dolby videos. Basically what I want is to extract frames from an HDR Dolby video as images and have those images not be the wrong color. Don't care if they are only 8 bit per color instead of 10 and all the all new stuff, just the closest that old fashioned 8 bit per color supports.
I added the statement marked // added for dolby hdr per the above doc, (spread across several lines), no luck, still bad colors.
Any hints of what I am missing?
NSMutableDictionary* dictionary = [[NSMutableDictionary alloc] init];
[dictionary setObject:[NSNumber numberWithInt:kCVPixelFormatType_32BGRA] forKey:(NSString*)kCVPixelBufferPixelFormatTypeKey];
// added for dolby hdr
dictionary[AVVideoColorPropertiesKey] = @{
AVVideoColorPrimariesKey: AVVideoColorPrimaries_ITU_R_709_2,
AVVideoTransferFunctionKey: AVVideoTransferFunction_ITU_R_709_2,
AVVideoYCbCrMatrixKey: AVVideoYCbCrMatrix_ITU_R_709_2
};
AVAssetReaderTrackOutput* asset_reader_output = [[AVAssetReaderTrackOutput alloc] initWithTrack:video_track outputSettings:dictionary];
[asset_reader addOutput:asset_reader_output];
// from here we get sample buffers like this
CMSampleBufferRef buffer2 = [asset_reader_output copyNextSampleBuffer];
// then pixel buffer
CVPixelBufferRef inputPixelBuffer = CMSampleBufferGetImageBuffer(buffer2);
// then a CIImage
CIImage* ciImage = [CIImage imageWithCVPixelBuffer:inputPixelBuffer]; // one vid frame
then we use standard stuff to convert that to a CGImage/UIImage
