The other day, I posted an AviSynth script to reverse videos.
So last night, I was attempting to use Avidemux to correct a wrong aspect ratio (didn’t exactly work the way I wanted, I got something like 32:9), and noticed this in the filters:
Why I never noticed that before…
EDIT: Tested it out. It doesn’t work if the video codec is set to “Copy,” and even then, it only reverses the video. However, I assume you could save the audio, reverse it in Audacity, and replace it. Somehow.