Unable to get hardware accelerated transcoding working with my Intel 5 235 in the Plex Docker

Plex Media Server NAS & Devices
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Server Version#: 1.41.8.9834-071366d65

I’m using the community app on Truenas 25. Here I chose the “Plex Official Image”. The server version is the number I could find for the “App Version” here.

{8EC9A5B0-D70A-4F0E-8ED9-3E47F2C869DC}
{8EC9A5B0-D70A-4F0E-8ED9-3E47F2C869DC}1106×367 16.4 KB

When I start a stream that needs to be transcoded, my iGPU is not used, even though I’ve actively assigned it for transcoding (see image below)

image
image557×173 11.3 KB

I can get Jellyfin to use my iGPU, so it seems the drivers should be in place.

My TrueNAS is running with a Intel 5 235 from this year https://www.intel.com/content/www/us/en/products/sku/241674/intel-core-ultra-5-processor-235-24m-cache-up-to-5-00-ghz/specifications.html

The logs from “Plex Media Server.log” says:

“Jul 05, 2025 10:19:19.305 [140194000243512] DEBUG - [Req#1c8f87/Transcode] Codecs: testing hevc (decoder) with hwdevice vaapi
Jul 05, 2025 10:19:19.305 [140194000243512] DEBUG - [Req#1c8f87/Transcode] Codecs: hardware transcoding: testing API vaapi for device ‘/dev/dri/renderD128’ (Intel Arrow Lake-U [Intel Graphics])
Jul 05, 2025 10:19:19.306 [140194000243512] ERROR - [Req#1c8f87/Transcode] [FFMPEG] - Failed to initialise VAAPI connection: -1 (unknown libva error).
Jul 05, 2025 10:19:19.306 [140194000243512] DEBUG - [Req#1c8f87/Transcode] Codecs: hardware transcoding: opening hw device failed - probably not supported by this system, error: I/O error
Jul 05, 2025 10:19:19.306 [140194000243512] DEBUG - [Req#1c8f87/Transcode] Could not create hardware context for hevc”

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Can you please provide the entirety of your PMS logs? It seems that there is a bit of history of changes with TrueNAS with how it handles or allow users to handle “applications” (jails, vm running docker, docker, etc) and their accessibility to iGPUs. For instance, with jails HW transcoding wasn’t possible. For your setup, is this a Docker container or LXC?

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This is a container :slight_smile:
As far as I can see, this should be the container in question: https://hub.docker.com/r/plexinc/pms-docker
At least that’s what I can see from this view where I “installed” it from

{A6DC499F-E0E4-4EA4-A3BB-83B8D06CE18F}
{A6DC499F-E0E4-4EA4-A3BB-83B8D06CE18F}1204×415 71.2 KB

Hereby the logs: Plex Media Server Logs_2025-07-07_17-16-05.zip (3.9 MB)
I started a new stream just before pulling the logs, so the relevant logs should be the latest entries :slight_smile:

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It seems I managed to solve it

I found this post on Reddit: Plex hardware transcode problems; Kaby Lake : truenas
Specifcally this comment: young_mummy comments on Plex hardware transcode problems; Kaby Lake

That lead me to try and nuke the ACL rights for my plex application folder in Truenas, and replace it with linux rights where I set everyone to have full access to the share.

After I did that, and restarted plex, it spent some time thinking. And after the CPU usage went down, I could now playback movies in the Plex app on desktop and mobile, and while doing this, see the iGPU usage rise significantly, telling me that the iGPU was now being utilized.

So it seems the problem was rights for the application folder for plex.

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