Replay Buffer creates a diashow

[NadCat]

I want to switch from Shadowplay to OBS mainly so I can record separate audio tracks. I've been trying different quality settings but I can't seem to find settings that result in exactly what Shadowplay offers: smooth high quality recordings of my 2560x1440 monitor up to 20 minutes long. I can live with the recorded files not being named after the game and I guess I can work around OBS not clearing the buffer after saving a replay but right now the recordings drop to about 2-3 FPS as soon as a lot starts happening on screen. Here's a short video: https://www.youtube.com/watch?v=jUGSbao4Nsc. It's already noticeable in the file size, I didn't even have to render that clip because it's so small

Is there something in my settings I need to change to get the desired result or is this something OBS just can't do?

Edit: OBS estimates the memory usage to be 7.2GB so that shouldn't be the problem

 

[koala]

For the replay buffer, OBS uses the "recording" encoder settings. However, for the recording settings you set "same as stream", so you got lost to the CBR rate control, where you additionally set a much too low bitrate of 6000 for a resolution of 2560x1440. CBR with 6000 at a resolution of 2560x1440 result in not very good image quality (too much compression artifacts, too much detail removed). This is not what you were asking about, but this is what I have to comment about the log you posted.

The log isn't complete, so it doesn't show the encoder statistics (you need to stop the replay buffer to get its statistics into the log), but your demo video suggests you have a lot of encoder overload. You use a Nvidia GPU with Nvenc as encoder, so this kind of overload is a sign of general GPU overload. This is usually caused by the game taking all GPU resources and leaving OBS with not enough. For example if you don't limit the fps or switch off vsync.

This is the help article about encoding overload that covers all this:

Encoding Performance Troubleshooting | OBS

OBS Knowledge Base. Learn best practices to solve encoding performance issues

obsproject.com

 

[NadCat]

Okay that's super weird, in the stream settings I've set VBR with 50k Kbps as rate control. I'm trying to adjust the recording settings separately right now but OBS keeps crashing when I switch to VBR

 

[koala]

If you care for quality, use CQP as rate control. Not CBR, not VBR. The CQ value is the quality to choose, from 1..50. The lower the CQ value, the higher the quality. Sane values are 15..30. Lower values require huge amounts of memory in the replay buffer, so you might want to set it not too low. Perhaps play around 23..26. A quality "indistinguishable" from the original is about 18, but I doubt you have enough RAM to use that with the replay buffer. That's better for direct recording without replay buffer.

By using CBR or VBR, you're wasting space for low motion scenes and sacrifice quality for high motion scenes. Both will not happen with CQP.

 

[NadCat]

So NVENC with CQP and a CQ level of 23 should be able to produce videos with a high enough bitrate? Because I still get single frames when testing with Armored Core. Normally I'd assume that my graphics card isn't strong enough but Shadowplay doesn't have any problem creating a 60 FPS recording. The log does say "Video stopped, number of skipped frames due to encoding lag: 2888/27477 (10.5%)" but the video lacks a lot more frames than that

 

[NadCat]

So I changed nothing but it works now. Thanks for the CQP tip

 

[qhobbes]

With CQP, you are picking a quality level, not a bitrate. The average bitrate will depend on the content and quality level.

1. You are running Windows 10 21H2, which has not been supported by Microsoft since June 2023. We recommend updating to the latest Windows release to ensure continued security, functionality, and compatibility.
2. One of your audio devices has a sample rate that doesn't match the rest. This can result in audio drift over time or sound distortion. Check your audio devices in Windows settings (both Playback and Recording) and ensure the Default Format (under Advanced) is consistent. 48000 Hz is recommended.
OBS Sample Rate: 48000 Hz
FxSound Speakers (FxSound Audio Enhancer): 44100 Hz
Microphone (2- Scarlett Solo USB): 48000 Hz
3. You are running an old version of OBS Studio (27.2.4). Please update to version 29.1.3 or newer by going to Help -> Check for updates in OBS or by downloading the latest installer from the downloads page and running it.
4. Run OBS as Admin. Right click on the OBS shortcut, properties, advanced, check box, ok, apply, ok.
5. In the encoder settings, uncheck the box for Psycho Visual Tuning as that uses additional GPU.
6. Remove Display Capture and use Game or Window capture for your game.