HW transcode revert to SW transcode with intel arc and HDR tone mapping enabled

Plex Media Server
,
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I’ve stumbled upon an issue where when I start streaming an episode it starts out in HW transcoding but when it reaches the end credits it switches over to SW transcoding.

This decision is the passed onto the next episode that will be played (plex continues with SW transcode instead of going back to HW transcode).

I have had start/end credit detection running as a scheduled task, but since this issue I have disabled this but even tho the button “Skip credits” is gone it still goes into SW transcode as soon as it reaches the marker in the metadata for the file.

In the included logs I have reproduced the problem doing this:

  1. Starting the episode (HW transcode works)

  2. Scrub to the middle of episode (HW still works)

  3. Scrub to the end credits (here the SW transcode starts),

  4. Then i press “Next” to start the next episode. When the next episode starts it is still in SW transcode, not reverting back to HW transcode even tho its a completely new file that starts playing.

If you would reproduce this problem, make sure your episode has start/end credit detection so the file has metadata, start playing the video (HW transcode will work) then scrub to the end credits where you would get the “Skip credits” button and see the SW transcode kick in.

#UPDATE 2#

Seems to be linked to HDR10 transcode, only get this behaviour when i’m transcoding HDR10 content.

#UPDATE#

So with some further investigation, it does not seem at all to be the metadata/end credits.

When using Intel arc a310 and “Enable HDR tone mapping” in plex, when it reaches the end of a playback it reverts to SW transcode. But if i disable HDR tone mapping the HW transcode works as expected.

For now I have disabled the A310 and only using the iGPU. Do not know how to fix this, possibly a bug?

To reproduce:

  1. Select Intel arc a310 as transcode device
  2. Enable HDR tone mapping in plex
  3. Scrub to end credits in an episode (here it goes over to SW transcode, and it carries over to the next episode playing if using the “next” button in the player)

To “fix”:

  1. Select iGPU instead (UHD 730)
  2. or disable HDR trone mapping in plex

Server Version#: 1.41.7.9823
Player Version#: 4.146.0
<If providing server logs please do NOT turn on verbose logging, only debug logging should be enabled>
Plex Media Server Logs_2025-06-02_10-42-38.zip (2.7 MB)

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