Audio Sync Backup Issues

[offput]

OK, so I'm backing up my copy of the "The Office (US)" season one DVD as a bunch of mkv's and I'm having major issues with the audio. I tend to keep the original ac3 tracks (the highest quality english plus any commentary tracks), convert the subtitles to srt, encode the video at high bitrate xvid, and then shove it all in a matroska file. I prefer to do it all on my own (dvd decrypter -> dgindex + subrip -> virtualbudmod) rather than using gordian knot (too many things I'll never use clogging up the system). Now that my methodology has been described, I'll explain my issues.

So I started off doing the same I always do: open the demuxed m2v file in virtualdubmod resizing (in this case) 720x480 to 720x404 (16:9) and add in the streams (in this case 1 audio track, 2 commentary tracks, 1 subtitle track) then encode the file. The first problem I encountered was that the audio was coming in too early. I delayed it by 500 ms and then it was perfect at the beginning of the file but by two thirds of the way through the episode the audio was once again coming in too early. I figure that it could be an awkward frame rate messing with the sync but I'm a newbie when it comes to this stuff so I figured someone might have a) dealt with the problem and fixed it or b) knows some intimate details of some process in my method that I've failed to grasp.

One final comment. I'm not sure, but could the sync problems be because of the number of audio tracks I'm trying to mux in? Is mux even the right term? Dear God, somebody help me, I need my Office!! :(

[Guest]

I would guess that your problem comes from using VirtualDubMod on an M2V that contains pulldown. VirtualDubMod ignores pulldown flags. That will cause desync if the pulldown is not pure consistent 3:2 throughout.

You can try VirtualDub MPEG2, setting "Allow RFF flags" in the extended open options. The downside is that your IVTC options will be extremely limited.

You can also use DGIndex/DGDecode to serve the video via Avisynth. That's the mainstream approach.

[offput]

Thanks, I'll try that.

EDIT: Actually, I'm currently trying VirtualDub-MPEG2 but I wouldn't mind knowing how the second method of serving the video through avisynth works. Is there a guide on that specific process somebody could lead me to?

EDIT THE SECOND: On second thought, I'm sure there's tonnes of info about that out there, I shouldn't bother you guys with such trivial things...

[Guest]

Is there a guide on that specific process somebody could lead me to? See here:

http://neuron2.net/dgmpgdec/QuickStart.html

This document is included in the DGMPGDec zip file also.

[J_Freak]

offput, you can't mux multiple audio tracks in VirtualDub MPEG2.
If that's what you want, you'll still have to use VirtualDubMod to put them all together (audio streams & subtitles), after the video gets properly encoded.
You can test the sync using Media Player Classic before you mux.

[offput]

I realised that after trying VirtualDub-MPEG2 and did so but I found that using avisynth serving into VDubMod was much simpler and worked perfectly. Thanks for the excellent help regarding this issue.