If you only want to disable video transcoding, because your CPU is too weak, there’s a hidden boolean setting TranscoderCanOnlyRemuxVideo.
Look at https://support.plex.tv/articles/201105343-advanced-hidden-server-settings/ to find out where to set hidden settings on your platform.
On Linux I added TranscoderCanOnlyRemuxVideo=“1” to Preferences.xml and restarted PMS.
After adding this setting, clients no longer show the controls for selecting video quality and will always direct stream the video, but can still transcode audio tracks.
