Audio out of sync from demuxed program stream

Question

Hi All,
I've been trying to resolve this problem without any success. I recently ripped some video from a dvd in order to make a backup. I extracted the title I wanted as a muxed program stream. I then used MPEGStreamclip to demux into .m2v and .ac3 files. I imported these into DVDSP and burned the disc. The result is that the audio drifts out of sync over the course of the length of the video (about 1.5 hours). I've done this same exact procedure many many times and haven't had this problem before. In fact the video will play back in perfect sync in both MPEGStreamclip and VLC. I did notice when importing the files into DVDSP that the length of the ac3 file shows a difference of almost 4 seconds (shorter) than the video. So obviously this is the problem. I just can't understand why if the video plays back perfectly its not being extracted properly by MPEGStreamclip. I also tried demuxing with BBDemux, which produced the same result. I then tried with the demux tools in ffmpeg and that process started creating numerous different versioned files of the original file and actually ended up running out of disc space.
Has anyone run into this problem before and found a solution?
Thanks,
Chris

Answer 1

Ok, I understand what you're doing now. But you're losing some quality by going to 422 and then back to m2v again, not to mention the extra time required for the encoding.
Thanks,
Chris
KADVD wrote:
Hi Chris,
I have used this method frequently when issues arise,
I use the original "Video TS" from the DVD, open,
Then open Streamclip, select the VOBs in the TS that don't end in a zero,
and drop them into the streamclip window, singly if needed, then convert
to (I prefer) pro res 422 SQ, I like the results better than DV.
assemble if needed in FCP, match sequence settings to clip, and
verify audio and video are in sync, then use compressor to create
your m2v and ac3.
Depending on how the original DVD was authored, menus, tracks etc.
the ".0" VOBs will frequently contain a 1 sec. black slug, this can
throw the audio out of sync when the video is extracted.
if there is a motion menu this will become a video clip, usually
in VOB "1.0", you probably don't want that.
Hope this is a clearer explanation.
J>H<L</div>