gradual audio desynching

[pennywyse]

I've been trying to convert a video clip from divx to mpeg-1 for about a week now using tmpgenc... the source video is 30.013 fps, making the total for the video 20048 frames... if i extract the audio separately and then try to use the extracted audio with the original video, making an ntsc vcd, the framerate is 29.97 fps, making the total 20013 frames... this causes a gradual audio de-sync by the end of the video, off by about a second and a half as near as i can tell, and the audio is behind the video, if that matters... ive searched this forum for any help on this and tried all of the solutions, but none worked... i have also tried saving the video with a different compression method using virtualdub, but to no avail... thanks if you can fix this...

[pennywyse]

ok, ive extracted the audio as a wav file and it is 11 mins and 7.979 seconds long... the video is 11 mins and 7.974 seconds long... i am pretty sure that 5 thousandaths of a second would not be noticeable hardly at all so i have no idea what is wrong...

[Mirror_Image]

See if this is of any use:

http://www.doom9.org/virtualdub_procedures.htm#mansynch

[pennywyse]

ok, i went there and i am going to try to use that procedure tomorrow... i am not sure it will work though, as the audio is synched fine is my original avi, just goes bad when i try to convert to vcd...

[Mirror_Image]

Yep, when you drop the framerate, the movie time lengthens, but the audio does not. I used to do DivX captures and synch the sound in VDub by increasing the frame rate, and thus had to deal with this to when I went to convert them to VCD. It's a pain!

[pennywyse]

i converted one of the avis to 29.97 fps and i will post tomorrow with the results on how well it makes an xvcd... thanks for the help and the link... people are too damn reluctant to even read posts about audio synching problems...

[abularkin]

If the above method doesn't work you might try compressing the wav file w/ an audio editing program like cooledit or soundforge to match the length of the video.

[pennywyse]

ok, converting the avi in virtual dub to 29.97 worked, thanks alot for the help... how come converting it to 29.97 with tmpgenc caused the desync? it seems like they would be kinda the same thing...