There are several codecs out there appart from DivX. These are Xvid, VP3, WMV 9 and Real Video.
Xvid is gaining a lot of popularity on Afterdawn.com’s wetsite for some reason. The quailty and encoding time is very like DivX 5. The only differences I can see are that it’s free and can be used as a capture codec to TV cards.
VP3 is another open source codec, but is quite rare on the net. From my experience, it has better colour reproduction that Divx at low bitrates, but images don’t tend to be as sharp. VP3 is half the speed encoding than Divx, so I wouldn’t recommend encoding it on a PII
WMV 9 is Microsoft’s video codec. From what I’ve heard, the quality is not as good as the others. The encoder is about the speed of Divx and playback is supported on all recent Windows platforms by default. I’d stay away from it as while it’s easy to convert to WMV, getting out of it is very very difficult.
Real Video 9 has very good quality, probably better than Divx as well and is a very fast encoder what I’ve experienced. Several problems: You need to have that crappy spyware & adware Realone player to playback these files and send, like WMV, once you convert the Real Video, it’s very difficult to convert to anything else.
Probably the best all rounders are Divx 5.03 and Xvid. My previous Pentium 2 400MHz was too slow to play encoded Divx 5.03 movies, but played Xvid perfectly. Encoding in both Divx 5.03 and Xvid went at about 2.5 frames per second on that machine!! If you wisht to encode Divx and want to be able to play it back smoothly on your machine, I would recommend sticking to Divx 4.01 or Divx 3.11. These are reasonable good quality and I had no problem playing back movies in these formats on a PII 400MHz PC.