I have a QNAP TS-453A (running plex server version 1.30.0.6359) and an appleTV 4k connected to my LG OLED HDR TV.
I have added 4K footage, and when playing it, the plex log shows loading it at 4k. What’s more, my TV says it is getting a UHD HDR image
However, Plex’s own compatibility guide says the 453A cannot serve 4K neither in hardware or software decoding. Actually it says transcoding, and I am watching original media, and I cannot see anywhere if the hardware decoding is used. I can remember back then when hardware decoding was a beta feature, it helped my playback a lot. However, I cannot find out for sure if I am actually seeing the full resolution and quality.
The NAS compatibility matrix is referring to a NAS’ capability to transcode media.
Based on your post it sounds like that particular file and its tracks can be direct played by your Plex client – so no transcoding is involved.
Monitor playback via Plex Dashboard → Now Playing.
If the media is direct playing or direct streaming (i.e. the video is not transcoding), then you are watching in the native format (4K HDR).
Direct Playing requires very little system resources. The Plex Media Server simply streams the file as it exists, with no changes. A Raspberry Pi can direct play 4K media.
Transcoding video is a completely separate matter. It is very compute intensive and requires a CPU or GPU that is up to the task. This is where the info in Plex’s NAS Compatibility Guide comes into play. It shows if the NAS can transcode video when using software (CPU) or hardware accelerate (the GPU).
