sound problem on low bitrate avis

[cthulthu666]

Hi.
My problem is when I encode a DVD with about 100KBit video (DivX4)and 96KBit sound everythings just fine except I have about 600MB.
When I encode with about 50KBit video and 64KBit sound, the sound mp3 is only half as long as the video and it´s not matching the video.
Does anybody know the reason therefor and maybe a solution. My aim is to get a reasonable quality with about 300MB on a 90 min movie.

P.S. the video file from first pass is good, it´s only a soundproblem.:confused:

[jggimi]

From the GKnot Help tab:audio-bitrates below 128 (in lame) can cause sync-problems (and sound terrible), because lame is automatically
downsampling to 32 or even 22kHz. i highly recommend to use
128 or 160 and nothing else. to avoid downsampling you have to add "--resample 48" to your lame commandline options if
you encode at low bitrates.