@waalkr This seems to be something related to Vegas and Ryzen CPU's from my own experience. I have a similar system to yours, a 2080 ti, Ryzen 9 5900x and 32gigs of RAM and still run into issues when trying to preview my footage. Meanwhile, I ingested some footage on a laptop that has an intel i7 11gen cpu with just an intel Iris GPU inside and it decodes the same footage a lot smoother for playback.

2 bits of advice for editing that I have found makes my rig perform decently.

1- Turn your preview from Best (Auto) to Preview and then choose either half or quarter when doing a rough cut and then putting it back to Auto for general review.

2- When you have to have a clear picture to edit finer details such as multi layered effects or timing a cut, highlight the area you want to view (try to keep this under 10-15 seconds) and then press Shift+B to pre-render what you've highlighted. It will playback your video as it renders slowly, but once it is done you will have smooth playback at full resolution at your targeted frame rate. Don't try to pre-render large section though as it will take a longer to finish the render and if you make any edits to the section it undoes the pre-render and you'll have to pre-render again to view it smoothly.

They know about it, it's existed since VP15. Many people complain about the lag at edit points, even if their media plays back smoothly otherwise. Some AVC media is buttery smooth across edit points even with low processing fade transitions but much more media causes the lag.

It's a bug that causes the GPU decoder to overload producing hundreds more frames than Vegas needs which are thrown away, and during that time the video lags. In this example, the correct GPU decoder load is about 26% (75w GPU power), and it spikes to 100%(105watts GPU power) while lagging.

Also as RogerS said, turn your GPU on, it assists in playback even without FX, though may increase instability.

There is nothing as far as I know, with this relating to Ryzen CPU's and Vegas. See my computer specs in my signature below. Also, you should do the same.

Everyone is posting but not really providing the necessary information. What footage? What created it? What is going on in your project? What effects/transitions/etc.?

Now... I have UHD 4K 25P 10bit 422 on the timeline. I can "bounce" around playing back any clip without any pause/stutter. With basic cross dissolves between the clips, everything plays back fine.

Using Good>Full.

Why is GPU acceleration off?

Can you say more about the media?

No clue why that's off, it was set to default settings. Ill enable that.

As for the media it is mp4 encoded with nvidia nvenc h.264 1920x1080 60fps

 

2 bits of advice for editing that I have found makes my rig perform decently.

1- Turn your preview from Best (Auto) to Preview and then choose either half or quarter when doing a rough cut and then putting it back to Auto for general review.

2- When you have to have a clear picture to edit finer details such as multi layered effects or timing a cut, highlight the area you want to view (try to keep this under 10-15 seconds) and then press Shift+B to pre-render what you've highlighted. It will playback your video as it renders slowly, but once it is done you will have smooth playback at full resolution at your targeted frame rate. Don't try to pre-render large section though as it will take a longer to finish the render and if you make any edits to the section it undoes the pre-render and you'll have to pre-render again to view it smoothly.

Thank you @SnarfConsortium that prerender trick is a life saver in the current state of my editing dilemma!!

They know about it, it's existed since VP15. Many people complain about the lag at edit points, even if their media plays back smoothly otherwise. Some AVC media is buttery smooth across edit points even with low processing fade transitions but much more media causes the lag.

It's a bug that causes the GPU decoder to overload producing hundreds more frames than Vegas needs which are thrown away, and during that time the video lags. In this example, the correct GPU decoder load is about 26% (75w GPU power), and it spikes to 100%(105watts GPU power) while lagging.

Also as RogerS said, turn your GPU on, it assists in playback even without FX, though may increase instability.

Also thank you for that info @Former user 

There is nothing as far as I know, with this relating to Ryzen CPU's and Vegas. See my computer specs in my signature below. Also, you should do the same.

Everyone is posting but not really providing the necessary information. What footage? What created it? What is going on in your project? What effects/transitions/etc.?

Now... I have UHD 4K 25P 10bit 422 on the timeline. I can "bounce" around playing back any clip without any pause/stutter. With basic cross dissolves between the clips, everything plays back fine.

Using Good>Full.

@Reyfox 10min clip with settings of nvidia nvenc h.264 1920x1080 60fps. On OBS. Then in the video all I was doing was standard cuts to clip pieces of the video together to shorten it. I also disabled resample on the video in vegas21

I made a short snip it and it actually looks like my CPU is spiking to 100% when these clips are being cut

Easiest way to bypass this problem, until a solution can be found, is proxies. Right click on the files in your project media bin, select "create video proxy", wait for that process to finish, and then set the preview quality to "preview (full)" or less. You should have silky smooth playback then.

@fr0sty LIFE SAVER! Even though its gonna blow having to wait for every media piece I add to my project to proxy... It makes it to where I can view it clearly in preview full without any spikes. Thank you so much

I made a short snip it and it actually looks like my CPU is spiking to 100% when these clips are being cut

Do you have GPU decoder on or off here?

Would not expect to see 100% CPU spikes with decoder on with that media and a 8core CPU.

I think it's searching for the I frame, If you do have decoder off here, and you got the time, can you do another screen recording playing back the same footage moving across edit points with GPU decoder on, no proxies, re-encodes or anything else?

Heres that updated video with the settings included again @Former user

Yeah that's the GPU decoder bug, what you can try is going into the encoder settings of OBS, and setting keyframe interval from auto to 1, and maybe change Max B frames to 1 if that doesn't help. If you don't see those settings change the view from simple to advanced

I'd uncheck legacy AVC decoding and set OBS to how Todd describes for what should be acceptable performance in VEGAS.

@waalkr Another possibility is to try capturing ProRes with OBS... might need a higher bitrate making bigger files but should also save the need for proxies for easy editing. These output tab settings seem to work on my laptop fine with 60 fps HD on the video tab:

Yeah, low fps at a simple cutting point without any fx (!) is an issue since years, sadly.
And it's definetly not an attribute of a PRO software.
Only time when i dont have this issue when i edit canopus HQ(X) avi files or a video with an easy codec like mpeg2, as i remember. H264 was always problematic at cutting point, and should be run smooth in 2024 with nowadays fast cpu/gpu.. just my 2 cents.

Using Best>Full with MOV files that are UHD 4K 10 bit 4:2:2 150Mb/s 25P footage, no problem. But then, I would not expect an issue with doing simple cuts and fades to be a problem with the hardware I am using.

Using Best>Full with MOV files that are UHD 4K 10 bit 4:2:2 150Mb/s 25P footage, no problem. But then, I would not expect an issue with doing simple cuts and fades to be a problem with the hardware I am using

@Reyfox This thread is about Vegas's poor performance with GPU decoders, you aren't using your GPU decoder with that format. Both OP and I show Vegas working much better without GPU decoder, and that should not be the case.

@Former user can you provide a sample footage that will use the GPU decoder for me to try and report back on?

@Reyfox This is file is characteristic of a standard distributable file that causes the problem https://www.dropbox.com/scl/fi/ld73pbtkx8bzk0sdg7a37/LG-Chess-4K60.mp4?rlkey=er2l6q37nnkhlh8hjchx9umw8&dl=0

It is not highly compressed, auto GOP of 250, the default setting for Shutter encoder. Handbrake I think it's more like 350 as default so will playback worse, and similar for internet files. The problem is the decoder getting stuck, not a slight pause or hesitation, which can be expected for non camera files depending on the frame you land on.

Simplest test is to cut out multiple slices throughout the clip and then playback from beginning to end. If AMD or Intel decoder behaves differently I'd like to know.

@Former user thanks for the clip. With VP21, here is what I did to it. I removed several parts of the clip, added the basic transition in some parts and have the original clip down to 1:25min. In VP21, Preview Quality>Best>Full.

Playback at the beginning was perfect. Where I removed parts, there was a slight drop in frame rate drop. Where I put a 1 sec transition, the frame rate would drop to 20fps, but then quickly back to 59.94fps.

Moving the cursor to different locations while the video is playing, the most difficult part of the video that took longer to "recover" was the sword fight. In about 3 seconds, it was playing at full frame rate.

Here is a screenshot of Task Manager. Note how much GPU RAM is being used. Playing the chopped up version, playback was very good with drops where it was cut or has a transition.

Playback at the beginning was perfect. Where I removed parts, there was a slight drop in frame rate drop. Where I put a 1 sec transition, the frame rate would drop to 20fps, but then quickly back to 59.94fps.

@Reyfox I would imagine a lot of people would be excited hearing that, but just to confirm could you try the same technique that I do here. I run Vegas scene detect, then select every 2nd scene, Cut, and Paste at the end, that way Vegas has no ability to cache and it reflects raw performance of Vegas decoding.

(playback 3x)

In this screencap Vegas decoder is overloading and lagging while as comparison Capcut performs as I would expect Vegas to, note the tiny slithers of 100% GPU decode, and compare that to Vegas decode getting stuck at 100%

Also could an Intel GPU decoder person try the same, but make sure you have enough CPU, it should be a test of GPU decoding without other limiting factors such as CPU.

I see similar performance with my laptop (QSV or NVDEC) with high decoder utilization and often not that high CPU use but low framerates. I don't really have the GPU or CPU to pull off 4k60 though. Will try my other machine and edit this comment.

On my desktop same issue with QSV and NVDEC. High decoder usage, low CPU usage. The main difference is on this more powerful system I do have instances of 60fps playback but then it drops back to 4 or 15 fps (which is unusable as a whole).

Using Scene Detection, and bouncing around the project, initially, low frame rates for a second, then up to the correct frame rate.

If I let it play from the start, 59.94fps all the way through.

Maybe someone else with an all AMD system could check and verify.

BTW @Former user what are your computer specs? None listed in your user profile.