does it make a difference....

[oxide]

if u separate the audio from the video file(source)and then put it back in the mpeg file(output). btw im encoding an avi to mpeg1. can u use Virtual Dub to do this ?

[Truman]

Yes, it makes a difference, because so you can use the encoders of your choise. Personally I use cce for video and toolame for audio. CCE's audio isn't the best, but far away from that.
VirtualDub isn't a MPEG encoder. For MPEG-1 conversion I recommend TMPG or Panasonic MPEG encoder 2.51. If you use TMPG, use toolame for audio. Panasonic's audio is OK.