Question / Help is there a 2nd monitor (obs preview) bug?

Matthew Paluch

Matthew Paluch

Member
After years of having a mediocre but solid streaming setup to twitch and mixer, and a rock solid local recording steup, nothing works as of about 2-4 weeks ago. I cant be more specific, and I was blaming other stuff.

I am beginning a "start from scratch with pinned posts and FAQs" rebuild today of all my Profiles, and will keep people posted, but came across an odd comment and wanted to see if this was some known issue before i tear everything to the ground and restart.

I am running OBS on a 2nd monitor, with preview on. Never been an issue, but is this an issue now? i came across one vague reference that you had to disable previews when streaming/recording, if obs was running on your second monitor. i cant find any ref to it in these forums, but thought id ask before i nuke my setup from orbit.

thx in advance!
 
Running the OBS preview window consumes GPU resources. In a setup where you're running right up against the limits of your GPU, turning that off can be of benefit, whether it's on a 2nd monitor or not. (Obviously running 2 displays instead of 1 consumes GPU resources too, but there are lots of good reasons to do so, and any decent GPU can do it.)

There IS a particular issue with Windows 10 running two displays at different refresh rates from the same GPU when using 3D accelerated applications.
 
YES, that was the issue i saw, refresh rates. my main monitor is 60hz, 2nd is 59... a lot of the reading i did was late and before bed so thank you for reminding me of exactly what it was. ill try to find a way to get them to be the same.

I also had read that a lot of people (like me) had webcams running at 1080p when 480p is fine for the relatively small size it takes up on most setups. i made that change but no effect. still getting 3.2 - 5.4% CPU usage, bitrate green, no warnings... 20-50% dropped frames.
 
That's not your issue, then. That refers to people who are mixing 60 (59.94), 120 and/or 144 in a single setup.

If you're actually having a performance issue it would help to have a logfile with a complete output session in it to troubleshoot.
 
11:58:34.083: Output 'adv_file_output': Number of lagged frames due to rendering lag/stalls: 4028 (22.1%)
11:58:34.084: ==== Recording Stop ================================================
11:58:34.335: Video stopped, number of skipped frames due to encoding lag: 7405/17709 (41.8%)

You're overloading your GPU, both for rendering and encoding. (Unlike NVENC, the AMF encoder consumes GPU resources).

https://obsproject.com/wiki/GPU-overload-issues

Start by capping your framerate. When the game is running at over 100fps, but OBS can't render or encode 30fps, there's no point in running those extra frames. Cap at 60fps or something and see if that frees up enough resources.

11:50:43.814: YUV mode: 709/Full

Change that to 709/Partial. You're increasing load and decreasing quality with this setting.

https://obsproject.com/forum/resour...t-color-range-settings-guide-test-charts.442/
 
thanks for the feedback. i guess i have a lot of bad assumptions about encoding. I dont understand how I can run the latest AAA title at 4k resolution and 60 fps but cant record it. Seems my assumption recording frames is way way easier than rendering them in the actual game is just flat wrong.

thank you!
 
Well I am confused, not new, but it is working. If you could Id love your comments/advice on WHY it is fixed however.

First, I took it off AMF encoding and went back to x264 (fast). And in the AMD drivers, I set it to force VSYNC as the game had no option.

i got 1-2.5 fps, abysmal.

So I decided to change graphics options in the game, but one at a time and test. i assumed Id need to change the source from 4k, but I was wrong.

The first thing I did, inside the game, was turn off anti aliasing. **instant fix**. With no other changes, I was recording at 1080p@48 with no frames dropped, rock solid.

Should i turn AA/AF on only in drivers? make a decision game to game? leave it off?

I cant thank you enough for your help - I think with this info i can (one day) fix my streaming. Im just thrilled to have local recording back.

any idea why the games internal anti aliasing wrecked OBS recording so badly?
 
Matthew Paluch said:
thanks for the feedback. i guess i have a lot of bad assumptions about encoding. I dont understand how I can run the latest AAA title at 4k resolution and 60 fps but cant record it. Seems my assumption recording frames is way way easier than rendering them in the actual game is just flat wrong.

thank you!
Click to expand...

OBS is not primarily a screen recorder. It is a video compositor and switcher that also encodes.

Because of this it offers features that other programs intended either solely or mostly for screen recording, like ShadowPlay, does not have. But these features come at a cost. OBS can record any number of arbitrary video sources, next to or even layered on top of each other, with transparencies. Doing this means performing a frame render separately from the one your game did.

Now, if you don't have any of those elements, then that render isn't all that difficult. But it still has to be done, where ShadowPlay basically doesn't-- screen recorders generally only offer limited overlay options that are limited in size and position, so only those portions of the screen need to be re-rendered.

The bottom line is that if you push your PC to the edge with game performance, there will not be adequate resources to also run OBS, and this will result in frame drops due to rendering lag, which is GPU overload.

Rendering load scales up with resolution. The idea of running a 4k60 game *and recording it at that resolution and framerate* in a single PC configuration-- without a 2nd PC and capture card, for a resource-intensive AAA title, is, generally not a realistic expectation at this time, not even with 20xx series Nvidia cards.
 
Matthew Paluch said:
Well I am confused, not new, but it is working. If you could Id love your comments/advice on WHY it is fixed however.

First, I took it off AMF encoding and went back to x264 (fast). And in the AMD drivers, I set it to force VSYNC as the game had no option.
Click to expand...

The AMF encoder is lower quality than the x264 one, and unlike NVENC on Nvidia cards, is not free to use-- it consumes GPU resources. It's also, ironically, considered generally lower in quality than QuickSync built into Intel CPUs.


Matthew Paluch said:
i got 1-2.5 fps, abysmal.

So I decided to change graphics options in the game, but one at a time and test. i assumed Id need to change the source from 4k, but I was wrong.

The first thing I did, inside the game, was turn off anti aliasing. **instant fix**. With no other changes, I was recording at 1080p@48 with no frames dropped, rock solid.
Click to expand...

That speaks to the specific loads produced by various features in specific games on specific cards, and unfortunately I can't speak to that.

Matthew Paluch said:
Should i turn AA/AF on only in drivers? make a decision game to game? leave it off?

I cant thank you enough for your help - I think with this info i can (one day) fix my streaming. Im just thrilled to have local recording back.

any idea why the games internal anti aliasing wrecked OBS recording so badly?
Click to expand...

I'm guessing that feature on your GPU in that game for some reason is very expensive, and did not leave enough overhead for OBS to work.
 
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