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HLS ignores MP4 transformation matrix
When playing an HLS .m3u8 playlist containing fragmented MP4 segments which specify a transformation matrix (defined in the Movie Header Box (mvhd) and Track Header Box (tkhd) atoms in ISO 14496-12), for instance a 90 degree clockwise rotation, the transformation is ignored and the video plays untransformed. Occurs both in Quicktime Player as well as well as Safari when playing the .m3u8 playlist. Concatenating the init.mp4 and .m4s files in the playlist into a file and playing the resulting file does apply the transformation, both in Quicktime Player and Safari. Am I doing something wrong? Are MP4 transformations not supported in HLS only? Rotations and flips seem like a pretty fundamental use case, otherwise video needs to be transcoded. Sample files to reproduce issue here: https://bugs.webkit.org/show_bug.cgi?id=222781
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Jan ’22