Routine drops in playback performance - visible FPS dropping

Plex Players
1

I am getting stuttering (appearance of FPS drops without any accompanying audio issues). The videos will play without issue for usually around 10-20 minutes, and then there will be a noticeable drop in fps with choppy movement that can last from 10-60 seconds and then will resume playing without issues until it happens again later. Usually pausing and playing will temporarily fix the issue until another 10-20 minutes goes by and it will happen again. Through the course of a 2 hour film, it happens routinely enough that itā€™s quite annoying.

I have been focusing on 24p (23.976fps) videos in trying to fix this since itā€™s particularly noticeable due to the already low frame rate. However, I have a sense that it may be impacting beyond 24p.

  • Windows 10 64bit fully updated
  • Intel I7 7700k
  • RTX 2070super fully updated drivers
  • Plex for Windows latest 1.40.1.2823-6f60f3a7
  • CPU/GPU is nowhere near 100% during playback
  • In the past Iā€™d been using Smooth Video Project with Plex until recently when I stopped so I am not exactly sure when the issue might have shown up since SVP possibly hid this issue.
  • Plex Web in Chromium might be unaffected after some testing.

The following I have tried without success:

  • Plex video processing set to low or maximum quality
  • Matching monitor refresh rate to video (23.976hz exactly)
  • Two different displays present the same issue (monitor/projector)
  • TV display ā€œfilm modeā€ on/off
  • Windows Variable Refresh Rate (VRR) turned on/off
  • Windows Hardware GPU Scheduling turned on/off
  • NVIDIA profile for plex set up with low latency off, vsync on, power adaptive, gsync off
  • G-sync fully turned on/off
  • Different configurations of mpv.conf including (video-sync-display-resample and interpolation=yes)
  • Software and hardware decoding
  • transcoding on/off
  • h264 and h265 files

Can anyone (or a developer) please let me know on any of the following:

  • Have I missed something in trying to fix the issue?
  • Is this simply ā€˜24p judderā€™ that Iā€™m reading about and something I canā€™t fix? Strange that it will play very smooth for so long until the poor performance shows up. I am under the impression that 24p frame rate issues should be more consistently present if noticeable.
  • Is this a Plex codec issue?
  • Does Plex for Windows use MPVā€™s interpolation and video-sync-display-resample by default to help alleviate display/audio sync issues due to mismatched clock rates?

Thank you very much!

2

I have narrowed the issue down to the NVIDIA GPU.

I have submitted a ticket with NVIDIA support.

Here is the text from my ticket to clarify:

I have spent a lot of time narrowing down an issue regarding 23.976 refresh rate and playing videos smoothly.

I have determined that with this NVIDA GPU, setting the refresh rate to 23.976hz on an HDMI monitor and projector and playing a video of the same rate (23.976) on different video players (MPV, Plex, MPC-HC) yields stuttering playback, usually after a period of time - up to 6 minutes where the visual performance will drop for a period of time where it may recover until it happens again. Pausing and playing temporarily resolves the issue. Over the course of a movie, it might happen 10 times or more.

The player logs donā€™t report any issues or dropped frames, however the FPS performance drop is quite noticeable. So it appears the issue is happening after video processing and on transport to the display.

I have tried turning off GSYNC, VRR, disconnecting all displays but primary and many other troubleshooting steps without success.

However, if I switch the display to the iGPU (Intel HD Graphics 630) the issue is completely resolved.

I have noticed that the iGPU as well as the iGPU on a laptop (both Intel-based) report a slightly different array of refresh rates for the display than the NVIDIA GPU does, if that is relevant at all.

It appears that there is a timing issue with the refresh rate. I can confirm that windows display settings shows the Intel GPU and the NVIDIA GPU both set to exactly 23.976hz so it isnā€™t clear how there could be a timing issue specifically on the NVIDIA GPU.

3

If my goal was more frames I would do the opposite: low latency ON and vsync OFF.
Although they both sound like 3D settings. May not affect 2D output at all. Itā€™s worth trying however.

1 Like
4

Thank you for your response.

Unfortunately this did not solve the issue.

5

This topic was automatically closed 90 days after the last reply. New replies are no longer allowed.