PMS HW Transcode fails after ~15 seconds of content

Plex Media Server
1

Server Version#: 1.41.0.8992
Player Version#: app.plex.tv

Server: Linux 64-bit
GPU: Nvidia Tesla P4
Driver: 550.90.12 (current as of this morning)

When I transcode a 4K HDR video to something lower resolution (like 720p SDR), initially transcoding works. I see a process pop-up in nvidia-smi. After ~2 seconds, the process disappears from nvidia-smi. The content that’s buffered in the player (~15 seconds) continues to play. When it reaches the end of the buffer, transcoding does NOT resume. The player just hangs.

nvidia-smi is empty and remains so indefinitely while the player is hung.

Plex Media Server.log (25.7 KB)

Transcoding settings:

  • [60 seconds] Default throttle buffer. Tried extending it to 120 seconds, to no avail.
  • [Medium] Background transcoding x264 preset
  • [Checked] HDR Tone Mapping
  • [Hable] Tonemapping algorithm. Tried others, to no avail.
  • [Unchecked] Disable video stream transcoding
  • [Checked] Use hardware acceleration
  • [Checked] Use hardware encoding. Tried changing, to no avail.
  • [Auto] Transcoding device. It’s clearly picking up the right device because I see it transcode briefly.
  • [15] Maximum simultaneous transcodes. But right now I’m testing with just one stream.

Confirmed that disabling hardware acceleration correctly falls back to CPU without issue. So it’s definitely a problem with Plex + GPU acceleration.

This morning I updated the nvidia driver from v525 and PMS from v1.28.0.5999. It worked before, so presumably one of those things are the issue…?

2

Unfortunately these logs are not usable (INFO/ERROR are insufficient)

  1. Please enable DEBUG logging - SAVE
  2. Restart PMS
  3. Recreate the problem
  4. Now download the Logs ZIP file
  5. Attach it here.
4

In the thread you split off, you said that the transcode problem was just in the web player. After setting up the test case again, I think you are correct. I tried transcodes with multiple other apps and it appears to be working.

I’m going to keep an eye on it for a couple days, but I think my problem is solved.

@ChuckPa: Thank you for your help.

P.S. I’d love it if Plex fixed the issue in the web player. There are times when opening a web browser on another computer is faster & easier than installing an application. Is there a way to vote for the dev team to fix that bug?

5

The issue with Plex/web will be fixed.

I don’t have the details but have been told they are re-writing it.