Not ASCII, however a cool hack using mpv is that it can display actual videos in a terminal emulator that supports true color output [1]. Just run the following command:

  mpv -vo tct video_file.mkv

Reduce the font size to increase resolution. Also, a GPU accelerated terminal like Kitty [2] is recommended, or the video will be painfully slow.

[1]: https://gist.github.com/XVilka/8346728

[2]: https://sw.kovidgoyal.net/kitty/