Leading causes of a/v de-sync?

[El Bart0]

I would like to record TV shows to MPEG-1 or MPEG-2 to be made into VCD or SVCD (or DVD in the future). I have a Pinnacle PCTV from a few years ago that I used in my Athlon 1Ghz system. I now have a much better system (XP 2400+ 512MB Corsair XMS, etc...check my computer specs) but I am still getting audio/video sync problems. I'm using WinDVR and the Vision program to capture directly to MPEG-1 and MPEG-2, and the a/v always de-syncs over time. Is it the card? Is it my system? The fact that I'm encoding in realtime? What causes a/v de-sync?

[Vejita-sama]

Capturing directly to MPEG could be the problem (PC too slow, but I doubt it).

Do you have the newest driver for your sound card?

What happens if you capture to compressed avi?

Are the audio in video always out of sync by a constant amount, or do they start off in sync (or off slightly) but get worst and worst with time?

Are you sure you're capturing at 29.97fps?

[El Bart0]

I have a hard time believing that the PC is too slow...I know there are people who have slower systems who get better results. So I'm with you on this one, I doubt that's the problem. I did a benchmark on the harddrive and it said it can sustain 15MB/s or more, which should be just fine for capturing, right?

I believe I have the newest drivers, but I can double check. Is using the onboard audio a bad thing? It's an Asus A7N8X Deluxe.

It starts off in sync and slowly gets worse and worse...and worse.

99.9% positive I'm at 29.97 fps. I will double check it.

[Hong Kong Phooey]

Have you tried the btwincap drivers for any comparison?

[El Bart0]

I tried them in my other system and they were more of a pain in the arse than anything else...they wouldn't initially install right (got a Runtime error in the install program), the video didn't display properly, and I think the captures came out messed up.

[slonocode]

I have a Hauppauge PVR 250 that also captures directly to mpeg. It exhibits the same behavior that you describe. The audio gradually gets more and more out of sync. One of the main culprits is audio PTS errors.

The best solution has been to capture using Program stream. If you have an option to use Program stream try it out and see if it helps. This has produced about 95% success rate for me.

HTH
Slonocode

[El Bart0]

Program stream? Could you elaborate on this?

[slonocode]

With my card and software I have options as to what kind of mpeg stream to capture with. Things like VCD, DVD, Transport, Program. It allows you to build a customized capturing profile as opposed to using the predefined profiles.

So far the only reliable way to capture has been to choose the Program Stream option. I'm assuming that they are just different ways to put together the packets.

I'm not familiar with your card or software but if you can customize your capture settings maybe look for a Program stream option.

[El Bart0]

Hmm, interesting. What program do you capture with?