Proxmox 8.2.2 kernel 6.8.4-2.pve - Plex Transcode problem

[riv76]

Hi all,
Recently upgraded to Proxmox 8.2 with default kernel 6.8 and discovered a problem with Plex transcoding, where Plex is installed insiede a unpriviliged container with ubuntu 22.04.
The problem is transcode does not works also if I can see transcode start with intel_gpu_tool; it start but does not work and it makes me think could be a gpu driver problem at Proxmox level, but I'm not sure at all.
So, I also changed the gpu mapping, using the built-in button in resource container configuration (Add, Device Passthrough), but still does not work properly.

ls -l /dev/dri/renderD128
crw-rw---- 1 root render 226, 128 May  3 02:25 /dev/dri/renderD128

same for Proxmox host and Plex container.

Any idea?
Thank you

 

[kesawi]

Plex has issues with Linux kernel version 6.8 and Intel GPUs.

See https://forums.plex.tv/t/ubuntu-24-04-hw-transcoding/873765/29 and https://forums.plex.tv/t/ubuntu-24-04-hw-transcoding/873765/40.

Intel appears to have changed some of their stacks and also dropped support for older CPUs.

The whole 6.8 kernel is a mess for HW transcoding due to issues with Intel iGPU support and also incompatibility with previous nVidia driver versions.To be honest I don't know why Proxmox have moved to it so quickly given all of the driver issues, not just with GPUs.

 

[riv76]

Thank you kesawi,
Super.
I was able to apply a workaround.

 

[Rannaa]

Thank you kesawi,
Super.
I was able to apply a workaround.

Can you share your workaround? I have the same issue

 

[riv76]

Can you share your workaround? I have the same issue

In Plex, Settings, Transcoder, i've unchecked "Enable HDR tone mapping".

For my case is not a problem, because for my TVs 4k HDR there's no need to transcode and usually transcoding can be used on my kitchen tv (1080p no HDR) or smartphones when not in wlan.

 

[kesawi]

For my case is not a problem, because for my TVs 4k HDR there's no need to transcode and usually transcoding can be used on my kitchen tv (1080p no HDR) or smartphones when not in wlan.

Tone mapping is used when content is transcoded from HDR to SDR, so if you are using Plex to transcode from 4K HDR to 1080p SDR on your kitchen TV and smartphone, then tone mapping will likely be required to avoid the colours potentially appearing washed out.

More details at https://support.plex.tv/articles/hdr-to-sdr-tone-mapping/

 

[Rannaa]

In Plex, Settings, Transcoder, i've unchecked "Enable HDR tone mapping".

For my case is not a problem, because for my TVs 4k HDR there's no need to transcode and usually transcoding can be used on my kitchen tv (1080p no HDR) or smartphones when not in wlan.

Yes found this out yesterday and turned HDR tone mapping off as well. Fingers crossed that it will be fixed soon since HDR tone mapping was working before.