Unexplained capture frame drop

[People11]

I've been noticing a frame drop for a long time, I used to think it was a problem with the rendered frame rate not matching the captured frame rate, but it seems to occur in stable rendered frame rates as well, and it's not a performance-induced problem, so I'm here for help.

First, log is here https://obsproject.com/logs/k4Sp4c5VeTOcUeN8
And this is the video I recorded with this weird frame drop: https://pixeldrain.com/u/RZ9so9YM

Detailed Description: I set my monitor to 60Hz and opened https://www.testufo.com/frameskipping , the page will display every square at 60 FPS, and record the browser with window mode. As you can see in the video, the square will intermittently have some skips, with the worst dropping to 30FPS, lasts a few seconds to a dozen seconds. But the skipping isn't caused by performance reasons, the browser display is fine (if the browser loses frames on its own, the page will show a prompt) and the encoder isn't overloaded, the only reason I can think of is some kind of problem with the capture.

 

[qhobbes]

1. Your log shows that your monitor is set to 120Hz, "08:17:12.046: refresh=120".
2. You are running Windows 11 22H2, which has not been supported by Microsoft since October 2024. Update to the latest Windows release to ensure continued security, functionality, and compatibility.
3. 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
CABLE Output (VB-Audio Virtual Cable): 44100 Hz
扬声器 (Realtek(R) Audio): 48000 Hz
[VIRTUAL_AUDIO_DEVICE_PROCESS_LOOPBACK]: 48000 Hz

If still having issues, post a new log.

 

[People11]

1. Your log shows that your monitor is set to 120Hz, "08:17:12.046: refresh=120".
2. You are running Windows 11 22H2, which has not been supported by Microsoft since October 2024. Update to the latest Windows release to ensure continued security, functionality, and compatibility.
3. 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
CABLE Output (VB-Audio Virtual Cable): 44100 Hz
扬声器 (Realtek(R) Audio): 48000 Hz
[VIRTUAL_AUDIO_DEVICE_PROCESS_LOOPBACK]: 48000 Hz

If still having issues, post a new log.

Problem 1 and 3 seems not related with the issue. I tried with 120Hz and recorded with 120FPS and the issue is the same, it'll drop frames randomly, down to half the setting.

I might try to reinstall the system to 24H2. But upgrading my system would take a lot of time to reconfigure my environment, so I'm not likely to reinstall the system anytime soon. I'll leave this hanging and reopen it when I have more information.

Log Analyzer seems to only be able to analyse some surface level issues, which I assume are DXGI/WGC/DWM capture related. It happends on all Windowed/Game/Monitor capture. This problem is also presented in the preview screen. So it's not an encoding problem.

 

[People11]

Update: this issue only happends when the screen Hz match with the capture FPS. It does not occur when the screen Hz is multiplied to the captured FPS (e.g. 120Hz with 60FPS or 60Hz with 120FPS). I'm not sure if this is some sort of accuracy issue, as the screen Hz doesn't seem to be stable at a fixed value all the time (e.g. 120Hz actually fluctuates between 119.996-121.xx), and it's possible that this fluctuation brings about a period of time where the capture doesn't accurately follow every frame in Vsync.

Considering the popularity of variable refresh rate monitors, I don't think there should be a way, or not be cared about to solve this problem