Are there any video formats or containers that support some sort of flag to have the video player just loop a video to the length of the audio track? There are several youtube videos for music that are animated, but essentially the same loop for over an hour. They're several gigs at full res, but could be reduced to a few mb. I imagine if it existed youtube would already be using it alongside some sort of system to detect looping, but nonetheless. I imagine back in the day effort was put into exotic video formats which support looping, maybe vector graphics rendering, and so on. Today there are no common implementations I know of.
