AV1 Decoding not working with HW Acceleration on nVidia RTX a4000

Plex Media Server Desktops & Laptops
1

Server Version#: 1.41.6.9685
Player Version#: Latest plex web and plex for Windows

I’m using a nVidia RTX a4000 which supports AV1 decoding. I can direct play AV1 files in plex fine but if I try to transcode them Plex either throws and error and ends playback, or in the case of Plex Web, the file gets transcoded with software (CPU) instead of Hardware (GPU). HW acceleration works with any other type of file.

Please let me know what, if any, logs I can provide that would be helpful.

2

Are you using a container or is this native on the host?

I have a RTX 2000 ADA gen and i9 AlderLake.

Both can HW decode.

Screenshot from 2025-04-15 22-23-27
Screenshot from 2025-04-15 22-23-27784×479 61 KB

I would appreciate seeing your server’s DEBUG log files ZIP

  1. Confirm DEBUG logging only SAVE if needed
  2. Restart PMS
  3. Wait about 60 seconds to stabilize
  4. Start the playback (10 seconds of playback will do)
  5. Stop Playback
  6. Download the Logs ZIP file
  7. Attach it here please
3

I’m using a docker container. The RTX Ada is a newer generation than my RTX a4000. However, it still supports AV1 decode per this matrix.

Video Encode and Decode GPU Support Matrix | NVIDIA Developer.

Here’s the nVidia driver details taken from inside the container (docker exec).

image
image735×412 22.8 KB

I will post logs shortly.

4

@ChuckPa Logs attached.
Plex Media Server Logs_2025-04-16_08-35-05.zip (2.4 MB)

5

Thanks for the logs.

They confirm the known issue (CUDA driver change for AV1 HW decode)

I am using an updated version.

I can give you that but unless you disable the container healthchecks forcibly reloading the image, it won’t survive a restart.

Can you manage that ?

1 Like
6

I should be able to manage that.

But can you just elaborate a little but on what’s the actual fix is?

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The actual fix is the dummy test frame (to confirm the GPU can decode/encode a specific codec)

8

Ok. Just let me know what to do.

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I don’t use docker ( I use LXC ), so don’t know how to disable the health check reloader

If you can find a way to disable the container reloading itself, I can send you a link to the image to confirm my results.

10

I think in compose it’s just.

healthcheck:
disable: true

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If I might ask, when will the issue /fix get to the main build?

12

I hope soon.

I don’t know where the “cut this as release” will be drawn.

There are a lot of improvements in the Engineer’s build I have.

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