MKV to AVI using MeGUI

[socrates]

I'm use MeGUI for converting audio-less mkv to xvid and then mux the resulting xvid and redone ac3 to avi using the same MeGUI. Most of the times every attempt comes out as I wish it to be. But certain files for eg: a mkv of 1.87GB and 1280x544, 23.976 fps attempted to xvid 720x304, 23.976fps and redone ac3 of 385 bit rate, muxed give me a resulting file size of just 1.17GB even when i suggest to MeGUI for a 2.2 GB file.
The same file with same setting comes back as 2.14GB when done with Avidemux. Please help me with suggestions on why MeGUI does this. Thanks...

[socrates]

I have this bluray rip in mkv with dts format which is 1280x528. Been trying to convert it to avi (xvid + ac3). I use MKVextract, then MKVmerge (these steps I know...no confusion there). MeGUI converts audio from DTS to AC3. The problem is with the video conversion. I select the output size to be 1.6GB with screen size 720x304, and at the end of conversion, the file always comes to 945MB (vid+aud). Please help in fixing this and suggest MEGUI settings. Thanks in advance....

[Baldrick]

I merged your both similar threads.

Are you using 2-pass or 1-pass encoding?

[socrates]

Oh well, thanks....I forgot that I had posted that months back. Consider that latest post as a separate issue. I do 2-pass with MeGUI