[CentOS] Open Source Video Codec and Container (alternative to Xvid)

Hi CentOS users

I am running a forum with small video clips (from YouTube and others). I 
convert those Macromedia Flash videos with:

$ mencoder example.flv -ovc xvid -xvidencopts bitrate=1000:autoaspect 
-vf pp=lb -oac mp3lame -lameopts fast:preset=standard -o example.avi

I use mencoder RPM from Dag Wieers

1) Its very generic command line to convert videos. What would you 
improve? The size is much bigger than the original FLV :(

2) Is there a real open source format what I should prefer? Can you say 
something about its quality?

3) Whats the most painless format for exchanging videos with Win, Mac 
and Linux users?

cheers
Simon

-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 189 bytes
Desc: OpenPGP digital signature
URL: <http://lists.centos.org/pipermail/centos/attachments/20080627/fef422f8/attachment.sig>