Audio mysteriously lagging behind Video... & More!

Beaker09 wrote on 7/13/2015, 4:51 PM
Hey folks, I'm a newer Sony Vegas user, had no problems until the past few weeks.

First I began getting some 1 frame visual glitches that resembled subliminal messages (spooky!) while previewing AND in rendered video. I turned off GPU acceleration and that has become far less frequent, so my Nvidia Gtx 970 could've been the culprit.

My biggest problem now is certainly audio that lags behind video on an unadulterated webcam track of me. It's irregular at best, sometimes -.5 seconds sometimes +1. I record on a logitech webcam & blue yeti mic, and overlay that track on top of gameplay. The webcam audio/video comes out of Windows Movie Maker as a .wmv file, and when viewed on its own in Windows Media Player there is no lag problem. Only in Vegas, during preview and rendered video. I often un-link the audio part of the track and slide it over a bit... hoping I eye-ball it correctly, but it's frequently off and needs to be rendered 4-5 times. This was not an issue for the first several months of using Vegas, and no substantial changes were made to my system lately.

A brand new issue today affected the webcam track, the video portion of me "froze" half-way through the timeline. The audio half of my webcam track were playing, but the video of me was locked still. I deleted the track and re-introduced it into the timeline, but it was still affected in precisely the same way. I rendered the project just in case is was a visual glitch only... but I was frozen in the finished version as well.

I rendered the .wmv webcam track into an .mp4 and this "un-froze" me if you will, and I was able to finish the project.

Still, why now? The only thing I ever change/update relating to Vegas or editing in general is Nvidia drivers, but as previously stated, I've turned off GPU acceleration for many reasons.

I've talked to Sony support and got nowhere. If there are any satisfactory solutions on this forum, or if anyone has an idea, I'd be incredibly appreciative. Thanks for your time!


musicvid10 wrote on 7/13/2015, 8:13 PM
System specs?
Source properties?
Project properties?
Audio drivers in Vegas Advanced settings?

Usually this is system or settings.

dxdy wrote on 7/15/2015, 8:14 AM
Did this start happening after a Microsoft Tuesday update to Windows?
Steve Mann wrote on 7/15/2015, 9:09 AM
What's the audio bitrate from the webcam?
If at all possible, don't use WMV.
Beaker09 wrote on 7/20/2015, 1:46 PM
To the first reply, my system specs should be in bio they are: i7 4790k, 16gb ram, Nvidia gtx970, Win. 7 pro. I'm unable to answer your other questions as I'm new to video production.

Concerning updates, I don't believe any Win. updates affected it. This problem is intermittent and unpredictable at best.

To steve: The audio bitrate of the wmv file I create is 320kbps. I have tried formatting it into mp4 before using it, (which shows a bitrate of 195kbps) and was problem-free for many days. Yesterday, the audio lag problem came crashing back, this time worse than ever. Time was completely skewed, the beginning of the track was off, middle was OK, yet the end was the worst I had ever seen. I will continue to render my wmv's into mp4's before using them, it seems less buggy, but sadly it hasn't solved my problem.

I feel lost, I've only got a year of experience in light video editing. All I know is Vegas, I've tried other programs but can't get into them. I may have mentioned, when I first began using it on this PC, no problems existed. All problems have been in the past few weeks.

Should I do a refresh and turn back the clock on my PC? I'm not one to band-aid a problem. Yet with my limited knowledge in this field, I'm struggling. Any further help is much appreciated!

PS: My render time has skyrocketed in past days, a vid that was previously 20 min render is now 60 minutes or more. No large variables have been changed, they're simple 10 minute, 3 layer videos. I will look for other threads on this matter.
balazer wrote on 7/20/2015, 8:25 PM
I'm with Steve on this. WMV is not a very transparent or well-supported format. Try to create your video in some other format like AVI or MP4. You might need different software to record from your webcam.
Beaker09 wrote on 7/23/2015, 10:55 AM
Great idea guys, for the past several projects I've used Adobe Encoder to switch the gameplay and webcam tracks from .wmv to .mp4. So far, the out-of-sync audio problem seems to be solved, hopefully for good!

Is .mp4 the preferred format, or is there one more suited for Vegas? I've noticed my render times have risen.

Thanks to everyone for the help! I'm surprised Sony support didn't suggest this.
musicvid10 wrote on 7/23/2015, 12:10 PM
And your system specs are not in your profile . you need to check a box to do that.
john_dennis wrote on 7/23/2015, 11:49 PM
"[I]you need to check a box to do that.[/I]"

When logged into this forum, navigate to:

The check boxes look like this.