another audio sync problem

[BowlPacker]

I hope someone can help...

I captured some 30 min tv shows using virtualvcr and ati tv wonder, with picvideo mjpeg codec. I then used virtualdub to scan the stream for errors, cut out commercials and create a final .avi (direct stream copy, no filters at all).

I viewed the final .avi with Media Player Classic and audio/video sync is fine, so I encode with TMPGEnc Plus to MPEG-2 (CBR, MPEG audio 224 kpbs) and the audio in my resulting MPEG is out of sync. It's doesn't seem to be a creeping out-of-sync, it's out of sync early in the video and late. And out of 9 episodes, 7 seem to do fine, but 2 have this problem and all were captured and processed identically.

So I went back and viewed the final .avi in Virtualdub with the preview and, sure enough, it is out of sync there, too. So Media Player Classic is somehow compensating for the sync problem? If so, how can I figure out what it's doing so maybe I can get rid of the problem when I create the MPEG-2?

[FOO]

Look at the AvI with Vdub and search for dropped frames.
edit->next drop frame
If there's lots, then there will be a 33 ms AV sync at each one.

I have found a way to fix that without guessing.
I'll post it if you want.

[BowlPacker]

I get "no next dropped frame found" (when starting from frame 0). In media player classic, if i look at the stats while the video plays, it has two vlaues "sync offset (avg)" which seems to stay at 0 and "sync offset (dev)" which fluctuates between 2-8ms. I wonder if that is some clue? I can't find any documentation as to what those values represent.

[spiderman2k1]

if window media player plays it fine then use tmpg to encode it again with the wizard and it will come out fine. do not edit you have to encode then edit tmpg uses windows media player

[FOO]

I note you are using ATI.

I have a ATI 8500
If I capture with ATI supplied templates I get perfect sync.
If I capture with 3rd part codecs ( PicVideo MJPEG) I always
get 650 ms Audio ahead of Video. I just set the delay in Vdub to 650
and frameserve to the encoder. it works good.

I tried to get ATI to pay attention but no luck

[BowlPacker]

Thanks for the replys - I didn't get time to mess around with it until last night. Upon closer srutiny, I found my source .AVI's seem to be ok as far as sync goes. But when I encode with TMPGEnc the resulting MPEG-2 is out of sync. Then, I let Ulead DVD Movie Factory 2 encode the AVI and the resulting DVD is ok (I used MF2 to author and burn originally, also, but used TMPGEnc to create the MPEG-2's).

So there's something with 2 out of 9 of these identically captured AVI's that TMPGEnc Plus didn't like. I did do the thing to extract the audio out with VDub and feed it into TMPGEnc separately, but got the same out of sync results. The odd thing there was, when TMPGEnc got to 100% complete it hung there for another five minutes or so doing nothing. I thought it was crashed, but I left it and it finally finished. So I'm thinking there's something screwy with source data that TMPGEnc doesn't like.

Thanks for the replies, but I don't think I'll know for sure what the deal was.

[BowlPacker]

Narrowing it down further...

I use dynamic resampling in virtualvcr and my original captures are in perfect sync. I load these 2+ hr avi's into vdub, and cut out the commercials by creating multiple segments (direct stream copy) then append the segments back together in vdub to create a new avi. Sometimes, but not everytime, my new commercial-free avi is out of sync. It will be ok in one part of the file, but out of sync in another part. It doesn't appear to be a gradual loss, almost like one of the segments introduced the problem. It makes me wonder if there is some setting I'm missing in either virtualvcr or vdub? I've scanned for stream errors with vdub and always come up error free.

FOO - can you post that trick concerning the 33 ms lost frame sync issue?