Question / Help Frame drops

[Ranko Kohime]

I'm trying to track down an issue where OBS is dropping frames while in a stream, and that has become a whole new rabbit-hole.

Without streaming or recording anything, and without even having any sources on the preview, (there is a window source, but the window it's supposed to capture isn't open during the testing), I'm getting framedrops just moving around the statistics window, even when not streaming or recording.

This is a laptop, so I expect some compromises compared to a desktop, BUT:

• CPU never maxes out or even comes close to maxing out, even a single core (CPU clock speed is locked to 100% using pstate for testing)
• GPU is clocking up, and never sees above 25% utilization
• NVENC is used for recording/streaming, but it never exceeds 20% utilization

I'm stumped as to what could be going on here. I made a video showing what's going on:

Any ideas?

 

[Harold]

12:28:48 PM.677: Output 'adv_file_output': Number of lagged frames due to rendering lag/stalls: 885 (17.8%)

You're overloading your video card. You are not actually dropping frames.

 

[Ranko Kohime]

12:28:48 PM.677: Output 'adv_file_output': Number of lagged frames due to rendering lag/stalls: 885 (17.8%)

You're overloading your video card. You are not actually dropping frames.

In what way would that be? I show in the video that the GPU is not exceeding 25%, the video engine (NVENC encoder) is staying below 10%, and, reviewing it again, I noticed that both DROPPED during the movement that causes the frame drops.

If it is indeed the GPU being overloaded, how can I quantify that?

Also, you point out the difference between lagged frames and dropped frames, am I correct in assuming lagged frames are discarded before they reach the encoder and the encoder simply duplicates the previous frame to prevent dropped frames, or no?

When I stream to Twitch, although frame drops are not terribly high as in this example, they do exist, at least according to Twitch's inspector, thus why I'm chasing this in the first place.

 

[Harold]

Dropped frames are purely 100% a connection issue.
Rendering lag is purely a video card issue.
Skipped frames are encoder overload, so if you're using nvenc, that's still video card, but x264 would be CPU.