audio sync - separate video/audio sources

[billja]

I've searched the forums a bit but couldn't find anything on my specific problem, so I hope someone out there has some advice.

I have two copies of the same video. The videos are both about the same length (a little different due to a few extra seconds at the beginning/end). Video #1 is at 23.976 fps but no sound. Video #2 is at a lower frame rate (like 19.x fps) but has the sound also.

I used VirtualDub on Video #2 and saved the WAV file. I then loaded Video #1 and set the audio source to the WAV file I had saved. I changed the "Audio Skew" around to adjust for the few seconds that were offset.

Here's the weird part. If I adjust the "audio skew" so it's correct at the beginning of the video, by the middle and end of the video the audio is now out of sync. If I adjust the "audio skew" so it's correct in the middle of the video, then the beginning has the audio come late and the end has the audio come early.

Can anyone help? I thought what I did should have worked since the video and audio were the right length. Why would anything be "stretched" and thus out-of-sync here? Thanks much!

[JrEE]

I AM STILL NEW TO THIS BUT IT IS A POSSIBILITY THAT THE FRAME RATE COULD HAVE MESSED UP THE SYNC. ALSO IT DEPENDS ON THE QUALITY OF YOUR ENCODING SOFTWARE. YOU GET WHAT YOU PAY FOR.

[RzSwede]

I've got the same problem. Xvid --> DVD worked pefect I thought, coverted sound to AC3 and merged the mpeg video with ac3 sound in DVD Lab. The audio-visual sync is perfect in the beginning, but by half the movie the video is about 0.5 seconds before the sound... The video and audio comes from the same Xvid.

I used TMPEnc to convert the NTSC 23.9xxfps video from XVid to Mpeg2 using Pulldown 3:2 option. I used virtualdub to extract wav and encode to ac3 using besweet (ac3machine).

Any suggestions on where the sync problem occurs would be most appreciated