Divx with Dolby Digital 5.1

[Brain]

It seems a waste to convert the video great in Divx format and make the audio just Stereo mp3. I read a way on Digital Digest to make it Dolby Digital 5.1.
But is there a way to encode the mp3 in a surrond sound format?
That would save lot of space would think :)
Because in the guide it said when you Encode in Divx with Dolby Digital 5.1 Audio, you bacisly have to make it on 2 cd's because the bitrate for the video would have to be set way too low and you would get crummy video and great sound which defeats the peruse of making a GREAT Divx Video :)
Any thoughts?

[UncasMS]

1. you dont 'make it Dolby Digital 5.1. '

you leave it that way!

i.e. you take the original ac3 stream, which MIGHT be 5.1 (could as well be 2.0 surround or even mono!)
and of course it will tzake at least 2 cds since ac3 might be some 300-400 mb in size!

2. extracting the sound stream the right way will give you 2.0 surround in mp3!!!

for details
check my guide (http://www.divx-digest.com/articles/dvd_backup_guide/english/)