Why some Plex servers don't allow playing without transcoding but some others do?

Plex Media Server
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1

Player Version#: 4.43.4

I have two Plex servers set up sharing the exact same folder with video files:
Server Version#: 1.21.0.3744 (installed as a Synology package)
Server Version#: 1.23.3.4707 (installed on Ubuntu)

The exact same video file does not allow playing the original quality from Plex on Synology but it does allow playing it from Plex on Ubuntu.

I do have direct play enabled - what can be the problem?

Synology vs Ubuntu:

image
image1378×718 32.2 KB

image
image1007×497 57.5 KB

Media file details:

image
image839×596 59.7 KB

2

Any idea from anyone?

3

Could be one of the servers is considered to be remote (e.g. in combination with the Syno PMS being configured to limit remote stream quality)
Could be based on some aspects of the Sync’s configuration (e.g. PMS considering there’s not enough bandwidth to direct stream and not enough power to transcode at a better quality).
…

4

If you are trying to play a HEVC video in a web browser, you will always get transcoding.