1 Reply
      Latest reply on Aug 5, 2019 12:03 PM by domfecpedals
      MyCometG3 Level 1 Level 1 (0 points)


        I am working in color drift issue with AVAssetReaderVideoCompositionOutput.

        Do you anyone have any idea that how to fix the color drift w/ AVAssetReaderVideoCompositionOutput?




        My source is DV NTSC SD mov file. Source CMSampleBuffer has proper color info as nclc 6-1-6.


        When I use AVAssetReaderVideoCompositionOutput, resulted 2vuy imageBuffer shows color drift.

        - resulted CMSampleBuffer does not have proper color information.

        - Also CVBuffer Attachment does not have kCVImageBufferCGColorSpaceKey.


        But when I use AVAssetReaderTrackOutput, resulted 2vuy imageBuffer shows same color as original.

        - it properly contains CMSampleBuffer w/ nclc, and also CVImageBufferYCbCrMatrix attachment is available.

        - It has proper kCVImageBufferCGColorSpaceKey



        shouldPropagate: {
            CGColorSpace = " (kCGColorSpaceICCBased; kCGColorSpaceModelRGB; Composite NTSC)";




        I suspect if AVAssetReaderVideoCompositionOutput ignores source SampleBuffer's color tags so composition is not correctly tagged.

        • Re: Color drift w/ AVAssetReaderVideoCompositionOutput
          domfecpedals Level 1 Level 1 (0 points)

          Have you figured out any solution to this? I'm having exactly the same issue, AVAssetReaderVideoCompositionOutput doesn't contain the proper color profile tag as AVAssetReaderTrackOutput does, I have to manually set the color properties to the videoComposition to be able to correctly decode the color, however I don't know what's the best way to read source asset's color properties.