You can do that with mpv pretty easily.

mpv "http://SOURCEURL" --vo=caca

Example:

mpv "https://www.youtube.com/watch?v=xYQiqBwczB0" --vo=caca

OR, for a higher-quality terminal-rendered video:

mpv "https://www.youtube.com/watch?v=xYQiqBwczB0" --vo=tct