AIW 128 + MMC 7.1 + AVI Capture = Out of sync A/V?

[AngusMacGyver]

Hi,
I tried to use MMC 7.1 and the new display drivers from ATI to capture videos into AVI files. Always I get files with out of sync problem. I've tried to install a new Windows with the minimum necessary to capture video. I tried many resolutions and codecs and in all cases that problem occours. When I capture to MPEG, this problem doesn't occour. When I used MMC 6.3, i could use VirtualDub and I noticed that fps didn't stay stabilished in 29.97. When I used 352x240 it was about 30,2 and when I used 640 x 480 it was about 29,4. VirtualDub correct the a/v sync. MMC 7.1 seems doesn't do this.
Now, I'm using MMC 7.1 and every avi file captured is out of sync. Does anybody know what i have to do to solve this problem?
PS: I have to use MMC 7.1 because Brazil has PAL-M as TV standard and MMC 6.3 isn't compatible with it.

[patrickm]

set PCI Latency=0 in your BIOS. or if you don't have that setting directly, find a program that will do that inside windows (there are some, but i don't need them, so i don't know the names). this solves a lot of those problems.

[DigitalOv]

Is your Using an External AVI Codec (one not installed as part of MMC) you' get a A/V Sync Error..

becuase if you use and external Video Codec.. it had to load the ddl's etc etc before it records. while the Audio startes immediatly..

The Syncing problem can be resolved by cuting a lil bit off the beginning of the audio or video and syncing in premiere..

[AngusMacGyver]

First, thanks for reply.
The problem occours even I use native AVI format and the diference grows during the capture (at the beggining there is no diference and at final it is big - 10min of capture produces about 2 seg of audio ahead). So, if I cut, it won't solve the problem. I'll try to set pci latency as patrickm said. I hope it will solve.
Thanks again.

[AngusMacGyver]

Hello!
I've just discovered the problem.
I think my old sound card was the problem.
I replace it, and now it's OK.
Thanks, once again.

[StephanWolf]

I had the same problem, and switching to a new sound card solved my problem too. The funny thing is, only mmc had the problem. I could record with avi_io and VirtualDub just fine.

[AngusMacGyver]

I'm happy because you could solve your problem.
Something about MMC and VirtualDub:
I've noticed VirtualDub has a "syncronizer" (I hope it's correct, I'm not an English speaker) that adjust audio gap to keep syncronization. I don't know AVI_IO, but I think it does too.

[StephanWolf]

Dagnab it! I just thought my problem was solved, but it's not. The audio starts out in sync, but then gets more out of sync over time. Anyone have a solution for this?

[next]

When you look at your mpeg2 captures using mpegtools in TMPGEnc (demux) you will probably see 4 streams. A video, audio, padded, and private stream. Many times the A/V sync problems are caused by the private stream. Most demux/mux or ediditing programs do not address this private stream when they attempt to work their magic. The result is A/V sync problems.

If you look at the private stream it is a .dat file which contains a series of many 0's. My thinking is that ATI uses this private stream to compensate for A/V sync issues for use within its native software. It could be there to try to compensate for the many different hardware setups that exist (mainboards, sound cards, cpu's, bios, etc...etc). The minute you try and take your captures and cut/edit them in other programs problems may occur.

My solution has been to find a program that will address this private stream when editing. The only one I have found is M2-edit. M2-edit will allow you to cut and edit your capture and save it to a mpeg2 program stream with no A/V sync problems. You then have to demux/mux it to a SVCD program stream. I use Mpeg2vcr for this.

edir-

oops sorry....you guys were talking AVI. Disregard.



<font size=-1>[ This Message was edited by: next on 2001-09-23 20:38:43 ]</font>