Transcoding problem when only audio is being transcoded

You’re showing me a screenshot of the logs. Having the full logs ZIP file would be better but, in this case, you provided enough information for me to answer.

I suspect you have a lot of well-curated (structured) media in your Plex server.
Depending on the Linux kernel used, you can run out of inotify slots without realizing.

– Pre-5.0 kernels have a default limit of 8192 directories
– Post-5.0 kernels have a default limit of 65536 directories

The transcoder needs 2 inotify slots when transcoding any Dolby audio.
(The software they provide requires it).

The solution for you is to:

  1. Count up the total number of directories you have in use for your media
  2. Round up to the next multiple of 32768 (or 65536 if you have ample memory)
  3. Customize the kernel configuration.

Here is the How-To