TrueNAS SCALE 25.10.1 – Goldeye despite Intel Arc A310 (decode works, encode unclear) + Solution

TrueNAS General
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Hi everyone,

I’m running into a strange issue with Plex on TrueNAS SCALE 25.10.1 – Goldeye, and I’m hoping someone with experience in Intel Arc GPUs or Plex transcoding can help me figure out what’s going on.

:wrench: My setup

  • TrueNAS SCALE 25.10.1 – Goldeye

  • Intel Arc A310 (PCIe)

  • Plex Media Server (official TrueCharts app)

  • LG OLED55G26LA as client (webOS Plex app)

:clapper_board: The issue

Plex is transcoding a movie that my LG TV can normally direct play without any problem:

  • Video: H.265 / HEVC

  • Audio: EAC3 5.1

  • Container: MKV

The TV plays this file perfectly via USB or DLNA.
However, Plex still chooses HLS transcoding, and in the logs I only see:

vdec_hw_status=1

This confirms that hardware decoding is active, but I see no indication that hardware encoding is being used. The FFmpeg start command is missing from the log fragments I’m getting.

What the Intel Arc A310 is doing correctly

  • Hardware decoding works (confirmed in logs)

  • GPU is detected properly by TrueNAS

  • /dev/dri/renderD128 is available

  • The iHD driver appears to load correctly

  • The card runs stable and efficiently

What seems not to be working

  • No evidence that Plex uses hardware encoding

  • No h264_vaapi, hevc_vaapi, h264_qsv, or hevc_qsv in the logs

  • No Using device: iHD driver or VAAPI initialization messages

  • No -vaapi_device or QSV flags in the FFmpeg command

  • Plex appears to rely entirely on HLS transcoding, even when direct play should be possible

What I’m looking for help with

  1. How can I confirm whether Plex is using hardware encoding on the Arc A310?
    The logs only show decode status, not encode.

  2. Are there known limitations in TrueNAS SCALE 25.10.1 – Goldeye or TrueCharts that prevent VAAPI/QSV encoding from working with Arc GPUs?

  3. Do I need a custom Plex client profile for LG webOS to allow direct play of HEVC + EAC3?

  4. Are there specific TrueNAS SCALE settings (permissions, drivers, runtime options) required to enable Arc hardware encoding?

  5. Where can I find the full FFmpeg start command in the Plex logs?
    This is the only way to know for sure whether encoding is hardware or software.

Extra info

I can provide full log files, including the transcode session, if needed.

Any help is appreciated — especially from anyone who has the Intel Arc A310 working with Plex hardware encoding on TrueNAS SCALE 25.10.1 – Goldeye.

Thanks in advance!

Regards Zero3711

2

Here’s the full message rewritten entirely in English, including the title, polished and ready to post on the TrueNAS forum:

:white_check_mark: Update: Issue Resolved — Permission Problem on /dev/dri (Intel Arc A310)

Hi everyone,

I wanted to share an update because I’ve finally identified the root cause of my Plex hardware‑transcoding issue on TrueNAS SCALE 25.10.1 – Goldeye.

After extensive testing, GPU monitoring, and log analysis, it turns out the problem wasn’t Plex, TrueNAS, or the Intel Arc drivers. The real issue was surprisingly simple:

:wrench: The dataset containing /dev/dri had read‑only permissions.

I’m using an Intel Arc A310, and Plex was able to read the GPU device nodes, which allowed hardware decoding to work.
However, because the dataset was read‑only, Plex could not write to /dev/dri, which is required for:

  • VAAPI/QSV initialization

  • GPU surface creation

  • buffer allocation

  • hardware encoding pipelines

Without write access, hardware encoding cannot start at all.

:check_mark: Before fixing permissions:

  • Hardware decoding worked (vdec_hw_status=1)

  • Hardware encoding did not work

  • No “Video Encode” activity in intel_gpu_top

  • Plex fell back to HLS or software encoding

:check_mark: After fixing permissions:

  • I granted proper write permissions to the dataset containing /dev/dri

  • Plex immediately began using full hardware encoding on the Intel Arc A310

  • intel_gpu_top now consistently shows Video Encode activity

  • Transcoding performance is exactly as expected

So the Intel Arc A310 was functioning correctly the whole time — Plex simply didn’t have the necessary permissions to use it fully.

Hopefully this helps anyone else running into similar GPU passthrough or hardware‑transcoding issues on TrueNAS SCALE.

If anyone wants details on the permission settings or how I verified GPU activity, I’m happy to share.

Thanks again to everyone who helped brainstorm along the way!