I captured a 6hr. long .avi, (704x480, PicVideo MJPEG, 48000 16b), and the sound is fine, but when trying to encode either by frameserving from VDub into TMPGEnc or directly encoding within MainConcept, midway through the resulting mpeg2, all of the sound disappears.

Has anyone else experienced this or have any recommendations on how to correct it?