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> That videos sometimes use "Rotation", not "Orientation" (and Rotation is encoded in degrees, not the crazy EXIF rotation enum) Not technically degrees. MP4 e
by asveikau 7y ago
> That videos sometimes use "Rotation", not "Orientation" (and Rotation is encoded in degrees, not the crazy EXIF rotation enum)
Not technically degrees. MP4 encodes it as a matrix. (Now, there are matrices corresponding to degree transformations...)
- mceachen 7y agoI haven't seen that: can you give me an example? (The output of `exiftool -Rotation example.mp4` would be great!)
- asveikau 7y agoIt's been a long time, but I once wrote code to parse and rewrite ['rotate'] the matrices at a previous job. The "Matrix Structure" is in the 'mvhd' atom. See: * https://developer.apple.com/library/archive/documentation/QuickTime/QTFF/QTFFChap2/qtff2.html#//apple_ref/doc/uid/TP40000939-CH204-32947 https://developer.apple.com/library/archive/documentation/Qu... * https://developer.apple.com/library/archive/documentation/QuickTime/QTFF/QTFFChap4/qtff4.html#//apple_ref/doc/uid/TP40000939-CH206-18737 https://developer.apple.com/library/archive/documentation/Qu... [Some of the best documentation for MP4 that I've seen on the web is from Apple, since it grew out of QuickTime.]