Can the fastest computer in the world do this in OBS?

J

jasone

New Member
I'm running a 4090 gpu with a 7950x cpu. I record 4k 60fps through my mirrorless camera into a blackmagic capture card. No issues with the hardware. My cpu never goes over 5% and my gpu records on the P5 setting with 35% usage or less. If I put the preset on P6 or P7 the OBS encoder maxes out and I get stuttering....my gpu is not the issue at 35% usage.

So the question is..... Who in the world records at 4k60 on P7! Is this even possible?

Thanks.
 
A

AaronD

Active Member
It would take additional code, and effort to write and debug that code, to limit combinations that don't work...yet. Then someone will complain that they can't take advantage of the latest Cray machine.

So not all combinations of settings may be workable...yet.
 
koala

koala

Active Member
In case you're recording with Nvenc, you're recording with hevc or av1, since it's not possible to record 4k resolution with nvenc h.264. Nvenc has its own performance limit, since it's a dedicated circuit and somewhat independent from the 3D computing performance of the GPU.
According to https://docs.nvidia.com/video-techn...application-note/index.html#nvenc-performance Nvenc on the ADA chip is able to encode a full hd (1920x1080) video with p7 preset + "High Quality" tuning with 178 fps. In "Low Latency" mode, it achieves 282 fps.
You're recording 4k, that means 4 times the pixels, i. e. quarter the performance. That means, nvenc has 178/4 = 44.5 fps with the HQ tuning and 70.5 fps.
So if you actually set P7+HQ, Nvenc limits to 44.5 fps. P7+LL limits to 70.5 fps.

You wrote you record, not stream. It might come as a surprise, but if you're recording with CQP mode, the pX and quality tuning is irrelevant. These settings make the recording file smaller. For streaming, thus using CBR or VBR, this means less data to transmit, so it appears as you have more bitrate, so you achieve better quality. But for recording in CQP mode, just the recorded file gets slightly larger. But the visual quality is the same. You will notice no visual difference between a P1+LL recording and a P7+HQ recording. Only the file size will be different.

So use a pX setting that yields a high enough fps according to the above data sheet. The fps values are normalized to 1920x1080, so if you use a different resolution, scale by the amount of pixels.
 
J

jasone

New Member
koala said:
In case you're recording with Nvenc, you're recording with hevc or av1, since it's not possible to record 4k resolution with nvenc h.264. Nvenc has its own performance limit, since it's a dedicated circuit and somewhat independent from the 3D computing performance of the GPU.
According to https://docs.nvidia.com/video-techn...application-note/index.html#nvenc-performance Nvenc on the ADA chip is able to encode a full hd (1920x1080) video with p7 preset + "High Quality" tuning with 178 fps. In "Low Latency" mode, it achieves 282 fps.
You're recording 4k, that means 4 times the pixels, i. e. quarter the performance. That means, nvenc has 178/4 = 44.5 fps with the HQ tuning and 70.5 fps.
So if you actually set P7+HQ, Nvenc limits to 44.5 fps. P7+LL limits to 70.5 fps.

You wrote you record, not stream. It might come as a surprise, but if you're recording with CQP mode, the pX and quality tuning is irrelevant. These settings make the recording file smaller. For streaming, thus using CBR or VBR, this means less data to transmit, so it appears as you have more bitrate, so you achieve better quality. But for recording in CQP mode, just the recorded file gets slightly larger. But the visual quality is the same. You will notice no visual difference between a P1+LL recording and a P7+HQ recording. Only the file size will be different.

So use a pX setting that yields a high enough fps according to the above data sheet. The fps values are normalized to 1920x1080, so if you use a different resolution, scale by the amount of pixels.
Click to expand...
Wow. I knew I couldn't tell the difference between the P values. I was setting the preset as high as it could go assuming I would have more data to work with in post. From now on I'll simply set the preset to P1 and take the extra load off the gpu during recording. This keeps the fans quiet. OBS should blank out the irrelevant P settings when recording in CQP mode. Thanks!
 
sandrix

sandrix

Member
you no longer need to look at the work of the GPU, but at the load of the video core. The easiest is in the task manager. In msi afterburner+rtss you can also display this information on the screen. The P5 handles 4K60 well.
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