Jan Derogee show us that it is possible to have full motion video on Commodore Vic 20 with two audio track available. User can select which track can be played, this mode can be used for karaoke mode.
Video: monochrome, 192×160 @ 12 frames/sec Audio: 4bit @ 12kHz (user can select 1 track from 2 possible audio tracks stored in the same video)
Note the 3K memory expansion is needed for Full motion video to play.
All that is done with some highly optimized code, Cassiope and data is sendt over user port expansion with transfer rate of 58kB/sec. All transfer is handled by 6502 CPU.