www.makemkv.com

I have managed to rip my movie into a mkv and placed in on my NAS (home built running Opemnmediavault 5 and Plex Media Server.) I am getting really bad stuttering on playback though. I have done a bunch of research to try and narrow it down. I downgraded the Plex app on my Fire TV to a known version that works well with streaming 4k video.

Plex is transcoding when trying to play back the movie for some unknown reason. Is my network to slow? I am pretty sure it's a gigabit network. How can I test my network to see if it is indeed fast enough? If I totally disable video transcoding on the plex server, the movie will not even play from the Fire TV plex app. Please help. Thank you.

EDIT: Is there a way to force Plex to never transcode the video? If Plex is not the answer, what program are most using?

It's probably because there's no support for lossless atmos audio on the FireTV and it's trying to transcode that. Try selecting a different audio track from the mkv during playback.

I selected the Dolby Digital (ac3) stream when I play it back so I do not think it's the audio. Anything else it could be?