MP3 is the format that taught music to travel: small, scrappy, and welcome absolutely everywhere. It was born in 1993, Fraunhofer Institute, Germany, and its real weak spot is holding fine detail at low bitrates: it stays small by quietly discarding sound.
AVI is the veteran of desktop video: dependable in 1995, cranky about everything invented since. Audio Video Interleave: an early container that predates streaming and most codecs you'd use today. That makes it the right destination when what you need is opening old archives and humoring legacy Windows tools.