Audio/Video Sync Trouble

[stahlhart]

This one has me stumped.

ATI AIW, Catalyst 5.4 drivers, MMC 8.9

Capture .AVI using MMC (HuffYUV), open video file in VirtualDub, edit, extract .WAV to HD, frameserve .AVI to TMPGenc (m2v+mp2), encode .WAV to AC3, substitute AC3 for MP2, author DVD -- video runs too fast, way ahead of audio.

BUT: capture .AVI using VirtualDub (HuffYUV) instead of MMC (HuffYUV), all other steps identical -- audio and video sync perfectly.

All setup specs (that I am aware of) are identical in both cases -- capture resolution, audio sample rate, sample rate for AC3 conversion versus MP2 conversion, video encoding resolution/bitrate/quality, etc.

Is there something that I am missing in the MMC setup that creates a captured .AVI that is somehow different than VirtualDub? I may just end up sticking with VirtualDub since I got such good final results with it, but I'm just curious about what could be causing the sync problem going the MMC route (I tried this route first from learning how to at DigitalFAQ).

Used TMPGenc DVD Author 1.6 to author, by the way. TMPGenc is a slow encoder, but I'm liking the quality of the results I'm getting and will probably stick with it -- but could the sync problem be occurring in the encoding step, though?


C.K.

[rkr1958]

When you have the video-audio sync problem with MMC, does the video and audio start off in sync and then drifts apart? Or is it always out of sync by a certain offset? If it drifts, then the problem could be cause by a slight error in you audio capture rate.

See https://www.videohelp.com/forum/viewtopic.php?t=252570&highlight=
for discussion on this issue.

[stahlhart]

It starts off in sync, but then drifts after a couple of minutes at the most. It becomes noticable very quickly.

Thanks for the link here; I'll take a look into this further...

C.K.