Jerky Video Play Back

[Darren Lim Ch]

Hi All

Thanks for helping me in advance.

I encounter one very special problem.
I hosting my Jellyfin in my NAS (Synology 720+)
The problem is, when playback using jellyfin, no matter on chrome, jellyfin app iphone (15promax), or my android tablet. Its jerky. 

And this only happen on 60FPS video. It drop frame like 1-2 frames every 10 seconds etc.
The video play INSTANT even seeking, but the video looks weird and jerky.
If its 30fps video then its fine.

What weird is that, if i directly use VLC or Jellyfinplayer to play, all goes smoothly. Tried use INFUSE to play also its play smoothly

All tested in LOCAL network. LAN cable directly to Router.

Tried most of the setting, turning hardware transcoding on off, set thread to MAX, googled quite a few hours. No any solutions was found.

Any advise is appreciated. Thanks

*Attached is one of the video that is 60fps, play back is laggy IF use web browser, jellyfin app*

[TheDreadPirate]

Is Jellyfin direct playing or transcoding?