vcd's from the laserdisc days
there was even an attachment to play them on a playstation 1 way back
they were fairly popular in japan, but never caught on in the us. although for a brief time there were standalone vcd recorders that could be used just like a standalone dvd recorder, for people who wanted to step up to a digital media, but couldn't afford dvd recorders
true vcd is mpeg-1, which is pretty lousy compared to mpeg2 or mpeg4, quality is about the same as a vhs tape, and movies span 2 discs.