Why does syncing video at original quality require transcoding?



My Plex Server is running on the latest version of Windows and I have the Windows Store Plex app running on a laptop which is also running the latest version of Windows.

Plex app and Plex Server are at the latest versions.

When I sync a video I'm choosing to sync at original quality. "Original Quality" to me means that it should not need to transcode. My thinking is that it should just copy the original file. Can anyone explain to me why it would need to transcode the video before syncing it when I'm simply trying to transfer it at original quality?

Note: The laptop is fully capable of playing the video exactly as it is on the Plex Server. If I simply copy the file over from the server Plex can play it fine.

Just in case this makes any difference, the video files in question are H.265 (HEVC) video with 5.1 AC3 Audio.