Solved Video out of sync after render

I am having a problem with part of my video rendering out of sync. I had split a piece out of the video and then crossfaded the remainder to blend in. The finished .mp4 is out of sync after the crossfade through the end of the video. When I go back to check the .veg project, the video and audio are still perfectly in sync on my timeline. I am using Vegas 13.0 (Build 453) 64-bit. I rendered it with the same settings I always use and usually get great results.

I have not had this happen before. I need to get this resolved ASAP! Any thoughts on how to correct this?

Hi

That is a strange one

There are only three reasons I can think of:
1. Your Project Properties and Source Videos are using a different Frame Rate.
2. The original video has a problem and may have gone out of sync anyway, without the transition.
3. You accidentally Un-Grouped the Audio and Video components for video section after cross fade.


Steps to check:
1. Open the Project Properties tab and press Match Media button (top right corner). Navigate to exact same video and select it. This will make sure your project is using the same Frame Rate as the original video. When Frame Rates do not match, it can cause the Audio to drift out of sync, after rendering.

2. Create a new project and import the exact same video. Do absolutely nothing to it and go directly to rendering. Render the whole video and see if the audio goes out of sync. If it goes out of sync, you know there is a problem with source video.

3. Delete both video sections in your project and then re-import video. Cut it as you did before and add transition. Now re-render and see if it is fixed.

If none of the above works, I have one last solution after this.

Regards
Derek

Derek,

Thanks for your quick answer. You were right---all 3 of your reasons were playing a part!
The source video was out of sync at the same point in the video. I re-grouped audio and video, matched frame rate & re-rendered a number of times experimenting with fps.

It’s closer than it was, but still not quite right. What is your one last solution?

Thank you so much. Your wisdom is invaluable.

Nancy Hanson

If the source video is out of sync, it may be very difficult to fix.
There is one thing you need to do, as part of the diagnosis.
Import the problem video clip into a brand new project all by itself.
Do nothing to it.
Go to the very end of video clip and place timeline cursor there.
Now zoom right in as far as it can go, using the wheel on your mouse.
Is the Audio file showing that it is longer or shorter than the total length of the Video file ?
How many frames is it out of sync ?

There was a freeze in the source video, which was broadcast live thru Wirecast onto our website thru a fiber optic line in full HD 1920x1080 & simulcast onto Facebook. The freeze lasted 30 seconds and everything after that is out of sync, likely due to high CPU used for simulcast.
Tho the source video is out of sync after this point, the audio and video files are exactly the same length when I enlarge them on the timeline as you suggested.
I have managed to fix the sync problem so that it is perfectly lined up and perfectly in sync on the timeline. I have matched the source video frame rate, and re-grouped the components. It is just PERFECTLY in sync on the timeline BEFORE rendering---yet it is out of sync AFTER rendering.

Still working with it...