flickers/glitches in video after rendering in Vegas 22

Furqan wrote on 12/24/2024, 9:37 PM

Whenever I edit a cool video that's graphic heavy, I move to render it with this settings I have majorly used for all my projects (Internet HD 1080p 29.97fps NVENC).

But just after the rendering and the video is saved, There are flickers or glitches with the elements, texts or anything else superimposed on the videos.

I looked up on youtube for solutions, and found that I got to go to Options > preferences > File IO and click on 'enable legacy AVC decoding' and 'enable experimental HVEC decoding.' Then I got to go the Video tab and click on 'GPU acceleration of video processing' and turn that off. So I did that and rendered again, only to find that the solution worked somehow, but with the render speed quite low.

This is on Vegas Pro 22 (build 194)
My specs are: an i7 processor, an RTX 4050 and 16 gigs of ram.
I really need help to sort the issue out. Got a deadline to meet.

Comments

RogerS wrote on 12/25/2024, 12:54 AM

Is it possible to share a sample project for testing (is this issue specific to your media or Fx?)

Are you working in 8-bit full mode or 32-bit ACES?

You've already found the workarounds, though probably just the legacy decoding in preferences/ file io would resolve the problem and you could keep the GPU on in preferences/video. It's not clear if you tried that, so apologies if you did. Yes, disabling the GPU will dramatically increase render times.

Furqan wrote on 12/25/2024, 10:13 AM

Is it possible to share a sample project for testing (is this issue specific to your media or Fx)

Yes, below is a video as an example.
I don't think this has to do with media, video or fx added to them. one slight upgrade from 19 to 20 or 21 got me to this issue. It was fine all the way till 18 (for several years that I had been using).

Are you working in 8-bit full mode or 32-bit ACES?

No idea what that is. Help me understand that please?


You've already found the workarounds, though probably just the legacy decoding in preferences/ file io would resolve the problem and you could keep the GPU on in preferences/video. It's not clear if you tried that, so apologies if you did. Yes, disabling the GPU will dramatically increase render times.

Yes, I've tried that too. Didn't give any difference.
What I've been doing for now is open an empty vegas project and import the .veg file of the project I want to render as a whole media and render the video from there. But too slow a process. A 15 min video went rendering for about 60 to 90 min long.

RogerS wrote on 12/25/2024, 8:50 PM

Thanks, this video is clear.

Older and newer versions of VEGAS work differently so I don't think it's a general issue with VEGAS. There was a bug causing flicker with dynamic ram preview. Setting it to 0MB for renders helped with that. However I believe that was addressed around the time of VP 19.

For VP 21.300 and newer the video engine is being reworked leading to some visual glitches. I see that on my NVIDIA systems but it's media specific. VP 22.194 is much better and it isn't a problem here anymore.

There are other glitches I see in 22 with 32-bit full mode and ACES. This is where you change project settings for those:

If you can share a project or media that has this problem I'd be happy to test it (privately is fine as well). I have a RTX 4060 here.

Furqan wrote on 12/25/2024, 9:50 PM

I just figured out this morning! Very accidentally.

In Options > Preference > Video tab, I saw that the number of threads was 32 and just out curiosity I dragged it down straight to 1. Then went to render.

It worked. WTF.

I didn't had to play around with the dynamic ram preview.

I didn't had to turn of the GPU acceleration.

In all this happiness and jumping, I lost my earphones under the table.

But who cares, I got this shit figured!

 

RogerS wrote on 12/26/2024, 1:50 AM

I'm glad it worked for you. That doesn't help fix VEGAS though.

Furqan wrote on 12/26/2024, 11:24 AM

I did look at the 32-bit full mode (which was at 8-bit by default first). I reset the threads back to 32 and gave the render a go.

it almost worked. The flickering happened, but very less. yet flickering was still there.

RogerS wrote on 12/26/2024, 11:40 PM

If you can share a project or media that has this problem we can try to get VEGAS fixed without workarounds. Or check back whenever the next build is released.

Sging2 wrote on 2/24/2025, 11:27 AM

I am getting exactly the same, hence why I found this post. Its very random though, I can render the same project twice with same settings and I will get it on one, not the other. Its always on shots that may be black and white or if I have used the built in slow motion plugin, its fine on everything else. I am on Version 22 and Build 239. Its very annoying as my project is 45 minutes for a client and I have re watch it all every time I make a small change and re render. At the moment I juts cant trust Vegas