3.0b build 128 - PAL MPEG encoding A/V sync bug?

owlsroost wrote on 6/10/2002, 7:21 AM
A couple of us here in PAL land have discovered bad A/V sync problems when rendering to MPEG-2 with 3.0b.

The sources are PAL DV with 48kHz audio, rendered using the PAL DVD template.

The problem is that on playback the sound lags behind the pictures by at least a second after 5-10 minutes, and it gets progressively worse the longer the movie (so several seconds out after 30 minutes).

Replacing the 'MCMPEG' plug-in folder with the one from 3.0a fixes the problem, and further investigation suggests that just replacing the 'mpgaout.dll' file with an older version also fixes it (although I've only briefly checked this).

Anyone else seen this problem? (and comments please from SF!)

I've encoded several hour long projects in 3.0a with no sync problems, so this seems definately to be a problem introduced with 3.0b.

Cheers,

Tony

Comments

Clyde200 wrote on 6/10/2002, 3:51 PM
Yep. Exactly the same thing here in NTSC land... Main Concept default NTSC DVD MPEG2. By the end of a 25 min. render the audio is at least 1 sec off. Shoot... and they used to be perfect.

SonyEPM wrote on 6/10/2002, 4:25 PM


snuffy wrote on 6/10/2002, 11:11 PM
I am experiencing the very same problem with builds 127 and 128. I have
just installed the workaround of using the 3.0a encoder. No feedback on quality
is available with the workaround.

I did not have this problem before. I am encoding NTSC DVD format, using
variable encoding.

Were there any enhancements to the encoder with 3.0b build 128? If so, is it
worth installing the build and just changing the one module mentioned above?
Or should I wait for a build 129 to be issued to fix the whole problem?
owlsroost wrote on 6/11/2002, 2:16 AM
SonicEPM,

> Are you seeing the sync drift in software playback (what apps),
> during DVD playback, or both?

I'm using Windows Media Player 6.4, which is using the Ligos MPEG filters (lmpgvd.ax, lmpgad.ax, lmpgspl.ax, all version 3.5.0.57, as shipped with Ulead DVD Movie Factory) for playback. I haven't tried playing a 3.0b file from DVD, but I've been using the above playback scheme for some time and I've always found the A/V sync situation to be the same as playing from disc in a hardware player.

Tony
eheh wrote on 6/13/2002, 1:46 AM
I'm floating up this bug as it happens to me, too
SonyEPM wrote on 6/13/2002, 8:11 AM
We have fixed the a/v sync bug and will post a Vegas update asap. In the near-term, go to:

ftp://porker.sonicfoundry.com/

username: dude
password: sweet
folder: Vegas 3.0b MPEG fix

copy the file "mpgaout.dll" from the above folder "Vegas 3.0b MPEG fix" and drop it into

:\Program Files\Sonic Foundry\Shared Plug-Ins\File Formats\MCMPEG

and choose yes to overwrite.

Restart Vegas and you will not have the problem.
bcrabtree wrote on 6/15/2002, 12:11 PM
I note that the 3.0b update has been pulled - as per http://www.sonicfoundry.com/download/step2.asp?DID=375

"The Vegas 3.0b update has been removed temporarily. We have discovered two critical bugs and will post an update as soon as possible. We apologize for the inconvenience. If you are running Vegas 3.0, it is safe to update to Vegas 3.0a."

However, there is a third bug that I think I have identified - MPEG-2 files for DVD being about one-quarter larger than they should be.

Can SF please make sure they look into this. More info is in two of my postings in a thread pointed to below on our DVdoctor-hosted messageboard:

http://www.dvdoctor.net/cgi-bin/ubb/Forum6/HTML/001265.html

Bob Crabtree
(editor)
Computer Video magazine
bcrabtree wrote on 6/16/2002, 6:51 PM
Looks like what I've been seeing with files size differences is NOT a bug. Sorry.

Tony Field - owlroost - says:

If you are using the standard PAL DVD templates, these have been changed between 3.0a and 3.0b - the average bitrate setting in 3.0a was (I think) 4.2 Mbit/s, in 3.0b it's 6Mbit/s.

So if your earlier file was encoded using 3.0a this would account for the difference (the size ratio is about right).

Using my own templates (which haven't changed between versions) I get roughly the same file sizes.
===================
Bob C