Rotating video without re-encoding (MP4 etc).

[mustardman]

Before anyone jumps down my throat, I have done a global search on the doom9 forums, and have come across nothing of use.

It seems a common question to ask, but it also seems to be one that is quite elusive : rotating video (by multiples of 90deg) just like a JPG still can be rotated - without re-encoding.

I have searched wider, and there is a tool to rotate MJPEG losslessly, and there also seem to be a few tools that claim to rotate MP4 video losslessly (VideoGo, Video Cutter). However, it seems exceedingly unclear whether this process simply changes the way the video is displayed by the player (setting a 'display' flag in the stream), or actually rotating the video data in the stream itself.

Personally, I suspect the former. Rotating MJPEG is really a step up from rotating a single JPG image, but rotating a stream with any sort of past/future frame references would be hard.

Do any readers with superior knowledge on this subject have a definitave answer on this one?

Thanks,
MM