divx to mpeg huge size increase, no sound and double length

[shobimono]

I started converting all my Hack Sign avi's to vcd. So far all the conversions have worked just fine, the avi's went from 170-200meg avis to about 235 meg mpgs. Now I loaded up another episode and all of a sudden I have a 533 meg mpg with no sound and the "length" went from 23:35 to 52:50, with everything after 23:35 just black screen.

Using avicodec, the following is for the last avi that converted correctly.
Video : 179 Mb, 1063 Kbps, 23.976 fps, res. 640*368 (16:9), div3 = DivX MPEG-4 (Low-Motion), supported

The next file that produces the huge 533meg mpg had the following info
Video : 116 Mb, 691 Kbps, 23.976 fps, res. 640*360 (16:9), div3 = DivX MPEG-4 (Low-Motion), supported

What the heck is in this 2nd file that is causing the huge size bloat and loss of sound, extra blank screen time and how can I fix it?

TIA

[Tommyknocker]

I heard Ac3 format wreaks havoc with the size of a video. Since you do have a problem with sound, why not try these two files:

One -- Audio problem encoding in general

Two -- Ac3 format audio conversion