audio/video sync gradually drifting during render

bskousen · Post by **bskousen** » Wed Sep 28, 2005 5:49 am

I have a 2:10 min video with 5.1 dolby digital audio. I am using the trial versionj of MSP 8.0. I am a registered user of MSP 7.0, but I am trying to see if 8.0 is worth the upgrade. I cut some sections out and everything was still in sync if I did a preview. However, after rendering with smartrender enabled, I found that the audio gradually drifted from the video by the end of the video. We're talking about mild sync issue, but enough to make it unacceptable at the end. Anybody else having sync issues? Is smartrender causing it? Is there any way to lock the sync?

Devil · Post by **Devil** » Wed Sep 28, 2005 7:09 am

Do you mean 2 h 10 min or 2 min 10 sec? Ambiguous!

Before doing the cuts, is the synch OK?

Please give us more details of your hardware/OS, video format etc.

DVX · Post by **DVX** » Wed Sep 28, 2005 1:49 pm

I have seen the same problem. MSP 7.3 also has lip sync issues. The only fix I use is to keep the timeline to a max of 15mins.

bskousen · Post by **bskousen** » Wed Sep 28, 2005 10:00 pm

No, it's 2 hours and 10 min. I don't see why there should be any sync problems no matter how long or short the project is. The program becomes useless if there are unresolvable sync issues. I rerendered with smartrender, but have not yet had a chance to look at the result.

Maukka · Post by **Maukka** » Wed Sep 28, 2005 10:57 pm

I have a 60 min project and had lip sync problems at some point. In my case they appeared only when I bunrned to DVD. After spending a week in debugging, I found out that the rendered file was corrupt (it was diffiult to troubleshoot because on computer it played back ok, yet it posed a problem for the miltiplexing during burning process).

I solved the issue by deinstalling and resintalling MSP 7.3. Have you tried that?

I am not aware of any 15 minute limitation, at the moment my 60min project seems to render without any lip sync issues (I sure hopeit stays that way!!).

Maukka

robtywlak · Post by **robtywlak** » Thu Sep 29, 2005 12:05 am

Are you by chance using DV Type 2 source files?

DV Type 2 has unlocked Audio and can drift out of sync on a long file - Type 1 does not have this problem which is why I ALLWAYS capture in Type-1. Type-1 interleaves the Audio / Video data into one single AVI stream where Type-2 is Two SEPERATE steams.

More info please on your file properties and project settings would be helpful.

Regards,

Rob

DVDDoug · Post by **DVDDoug** » Thu Sep 29, 2005 1:07 am

Probably a corrupt file.

I've had the same experience as Maukka. (In my case, the files were MPEG-2, and I was using different Ulead programs.)

Using type I AVIs doesn't always help. Unless the files are MPEG-2 and fully DVD compliant, they will have to be de-multiplexed & re-multiplexed. In fact it is common for the sync problem to show-up only after rendering the final DVD or DVD file.

Here's one way things can go wrong -

During rendering, the program hits a slightly corrupted frame.

The program throws-away (or looses) the corrupt frame. The audio is unaffected.

Each time a video-frame is lost, the audio & video get further out of sync, with the audio trailing the video.