Interesting use case where one of my users uploaded a slow motion video to the forum and it played back at normal rate.  I noticed there is an HTMLMediaElement.playbackRate property to set the playback speed/rate, however I'm guessing this isn't set by the Invision Community forum software when it creates the embed code?  Anyone have any experience with this?

All we do is create a <video> HTML tag and put the source of the file into that tag. We don't control the playback rate.

Thanks @bfarber

The user uploaded it to YouTube and it did play in slow mo automatically.  Assuming there is something in the metadata of the video itself that identifies the playback rate (or recording rate) that they key off to detect and set the playback rate properly.  Maybe something for an enhancement in a future release for Invision Community forums.