Perfect MPEG2 capture loses audio sync AFTER encode... HELP

[BlizZ]

I have an MPEG 2 capture that's about 340+ minutes long. I captured it by hooking up my VCR to my Winfast TV2000XP card and capture it into 640x480 MPEG2 (optimal quality). The idea is to make these captures into DVDs after inserting chapters/menus. I've done it once already, and was satisfied with the results. This time, I have a SERIOUS problem that I can't seem to troubleshoot. Here goes:
I captured the MPEG2 and it's roughly 9-10 gigs. Plays great, audio/video in perfect sync. No problems. Using TMPGEnc, I encode the MPEG2 into another MPEG2, one that is roughly 4 gigs and in DVD spec in respect to resolution. It wants to take 100% of disc space, but I move it down so it only takes about 95% of disc space. I get the encoded MPEG2 file once it's done (about 5-6 hours) and I thought I should be set like I was the first time. I was wrong. The audio is out of sync from the beginning. I tried demuxing and then muxing the audio with the original botched encode file. It did nothing to help. So here's the next thing that I tried to do: I open up the botched encoded file in VirtualDub, skew the audio by delaying it 8000 milliseconds, save the WAV, then encode the MPEG2 in TMPGEnc AGAIN, this time selecting the afforementioned WAV as the audio source. It didn't work totally. I was checking towards the middle of the file and everything seemed in sync. But now, towards the end of the encoded MPEG, the audio is once again out of sync (and by a few seconds or more).
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It should be noted that when I encode the captured MPEG (the 10 gig one), I'm clipping a bit off the beginning and a bit off the end. But I did the first time that I was successful, too, and it didn't affect anything. But now, I'm back to square one. I've got the original MPEG2 capture and the botched encode that had the WAV as the audio source. I will recapture if needed, but that should be a last resort, as it is over 3 hours of video, and the original MPEG2 is perfect anyway. I need your help. If you have any ideas or have experienced similar problems and found a fix, please post.
Thanks.

[pixel]

I am just taking a guess, but I think you may be encoding to a hard drive which has a lot of stuff/has rarely been defragmented. This means the video and audio can be stored at other ends of the hard drive and it just can't keep up when playing. If you still have the original encode, try defragmenting the drive it is on then play it.

It may also be your media player/mepg2 codec, even on defragmented drives on my machine I have had vid/aud go out of sync due to poor codecs.

You will not have to re-capture again for sure. I am also pretty sure TMPGEnc is not the problem.

[BlizZ]

Thanks -- I forgot to mention that I scan disked AND defragged my HD (80gb WD 7200 RPM 8MB Cache) before one of my encodes (before I used the extracted WAV but after the first one). I have like 20-30 gigs free right now. I could free some up if needed, but would rather keep the stuff that I have for the time being. Any other ideas?

[pixel]

I can only think of a codec problem at the moment. (have you tried authoring to a DVD+-/RW and seeing if the final is in sync?)

Even without a defragmented hard drive, a standard home PC would probably never have to have a drive defragmented to keep aud/vid in sync, even on mine I have a lot of files scattered, but never sync problems.

Another idea could be using a different encoder.

Without knowing it your original captures may be out of sync, but that probably shouldn't be.

I'll see if I can think of any other reasons.

[BlizZ]

"Another idea could be using a different encoder."

Is there any other encoders that have an option to put it into DVD spec? (resolution/audio/etc...) I have flaskMPEG and it doesn't seem to be as easy to use as TMPGEnc. BBMpeg seems like it will take quite a while to even load the file.

Is there anything similar to TMPGEnc?

The original capture plays fine in both PowerDVD (playing media files option) and Windows Media Player. If it is the capture, I can capture it again if absolutely needed, but even then how will I know if the audio is in sync if I can't tell by playback?

I really am just puzzled as to why I'm having these problems this time. Had no problems doing this once before.

[pixel]

I believ FlaskMPEG just converts an MPEG into an AVI, not what your wanting.

The encoders which most people compare to TMPGEnc are Mainconcept and CCE, although I have never used them.

There is probably nothing wrong with the original captures so you shouldn't worry about having to recapture. (I always keep the source material until I know the final DVD works anyway.)

I still think the best idea is to burn a test DVD+-RW and see if it is in sync on your standalone, or even your PC DVD-Rom drive.

[FOO]

Question: Will the video play in sync in Vdub ?

What did you edit the original 10 gig mpeg with ?

Did you do it that way on purpose ? I mean why not capture
at a bitrate that will fit ? If you did I strongly reccomend
you capture to an AVI if you intend to edit and encode.
Editing MPEG2 is very problematic.

If it plays in sync in Vdub you can frameserve that to TMPGenc
to re-encode it smaller and it has a much better chance because
TMPGenc is receiving raw video instead of MPEG2

[BlizZ]

Ugh. I feel like a total dufus. I'm sorry. The original 10 gig video doesn't play in sync in Virtual Dub. It does play in sync in PowerDVD/Windows Media Player. I'm new to this stuff and didn't know to check in VDub.I am assuming that this means there is something wrong with the capture causing the audio sync problems. Should I recapture? Anything I can change to eliminate a bit of the risk of causing audio sync issues? Thanks.

[pixel]

Don't worry, I used to have sync problems with captures and it took me ages to solve them.

The best method is to capture to a dedicated capture hard drive, and also to do a quick format on the drive before each capture. This will definitely keep it in sync.

[FOO]

Vdub and the others are using different MPEG decoders.
What does Vdub claim as the frame rate ?
I know this can happen if the video has pulldown flags.
Possibly dropped frames do it also.

[BlizZ]

I might be able to have another HDD put into my PC. I will try that if all else fails. I find it odd that the first time I did this though, it worked fine. The VHS tape isn't old or beat up or anything. Would there be something problematic possibly with the way the tape itself was dubbed? I just captured the video again and the audio is still out of sync in Virtual Dub. Once again, however, it is in perfect sync in Windows Media Player and in PowerDVD 4. Since Windows Media Player and PowerDVD seem to be able to fix any potential sync issues with the MPEG file, is there anyway I can employ this while encoding it to a smaller size with TMPGEnc or another encoder that puts stuff in DVD format? I mean, once I encode the file, it won't play in sync in Windows Media Player or PowerDVD anymore.
Thanks alot for all your help so far.

[pixel]

It could be the header in the video is read by your MPEG2 codec and this keeps it in sync, but VDub will just read the file and hence it isn't in sync.

Make sure you are not doing an inverse pulldown as above mentioned.

You really should invest in another drive solely for capturing (for capturing MPEG2 to be later re-encoded 60GB may be enough. If you do not do a lot of caputring, you could partition it and store files on the other half, but DO NOT install your OS on it).

We have not yet found the source of the problem, so try capturing an AVI file, then see if the capture is in sync. Then re-encode it and see if it is in sync.

As you do not have a seperate capture drive, I will bet you are capturing to your OS drive. As your OS is constatly writing to that drive, you may find it knocks the audio out as soon as you start capturing.

You will probably be using the software that came with your card to capture this could be the problem. Try using a different program to capture (maybe just an all-in-one DVD authoring program like Ulead DVDWS to test).

[BlizZ]

Thanks. I'll try to capture to an AVI as my next thing. I'm assuming I need a codec for this. Should I capture with the codec in my PVR software that came with the card or should I use it and capture in Virtual Dub? I know the first time I capped a succesful video it was with my PVR software but whatever you suggest I will try. If there is a codec, are there any free AVI codecs that will output files of this length (~340 minutes) to roughly the same size (9-10 gigs)? Or just a bit more, like 15-20 gigs?
Thanks alot.

[pixel]

Sorry, I didn't mean you to capture the whole video, just a test clip to see if it stays in sync.

You should try capturing in AVI in VDub and also in your PVR software. I find that my captures in VDub are in sync, but in my video card software they are out of sync.

The HUFFYUV codec is free, but has huge file sizes, but doesn't use a lot of CPU power.
Divx is also free and has small file sizes, but uses a lot of CPU power.

[BlizZ]

Thanks. I'll try a test, shorter capture (maybe like 30 minutes) in AVI form. Where can I get the DIVX codec? What is the best one to get for what I need? Do I need a special DIVX player on my system (I've heard some contain adware) or will the codecs make DIVX stuff work in like PowerDVD/Windows Media Player? Thanks alot!

[pixel]

The divx codecs should be in the tools section , if not, just search for divx in google. Usually the codec suites contain both the capture codecs and the decompression (playback) codecs. The divx and huffyuv codecs do anyway.

You should only need to capture about a 5min or less test to see if it is in sync.

[BlizZ]

Quick update: I captured a sample and then the whole tape using the DivX codec and everything is in sync in and out of Virtual Dub, however, the quality is definitely a step down from MPEG2 (which wasn't really surprising once I realized that the original capture was only 4-5 gigs). Pixel and everyone else, I appreciate all your help and it seems like you've got me on the right track. I'll be making a post in the Capturing forum looking for tips on other AVI or even non-AVI codecs to use that may give me a better quality (at roughly 10 gigs or even up to 20)... One question though, do you think that my problem capturing in MPEG2 was that the file size was so large, or just something problematic with MPEG2 capping? If it's something to do with the large file size then I might have to look into getting a 2nd hard drive installed.

Once again, thanks to all for all your!

[pixel]

You should NOT capture to Divx, or any MPEG4 codecs for that matter because they are usually higher compressed than MPEG2.

The best codec is HUFFYUV, which is uncompressed.

The next, and one that I use if I am working with AVI is PicVideoMJPEG. This has adjustable settings, and you will not really notice the difference between this and HUFFYUV.

If you are working in AVI you usually need quite a big hard drive (my 80GB is strained when working with AVI).

I would almost definitely say it wasn't your hard drive that was giving you sync problems. It is most likely your capturing software or video card drivers.

Another thought is it could be your sound card. Some cheap soundcards (and onboard sound) have been known to cause audio sync problems.

If it is a cheap soundcard (like <£30) or onboard sound, try a friends sound card if they'll let you (preferrably a sound blaster).

The sound card thing is just a last resort, but it does happen.

[BlizZ]

MJPEG worked good. No sync issues capturing, no sync issues encoding. Thanks alot for your help -- you saved me a whole lot more headaches.