www.makemkv.com

I've ripped a number of 4K blurays now using my LG external drive on Mac. Image and sound quality is superb and I'm playing it back via a Synology DS224+ with 18GB RAM and playing back on a 2nd gen Apple TV 4K on a LG C2 OLED. I notice very occasional skips with the video (audio is unaffected) for just a second, I also notice after playing the video starts stuttering.

The stuttering is resolved if I exit Plex and go back, but what could be causing these issues? Everything is hard wired so I don't believe it's a networking issue and the NAS is only running Plex and Homebridge. Is it a bad rip?

Rip to disc and then copy to Plex.

That's what I've done but the rip has occasional 1 second stutters. How do I prevent this from happening when I rip the discs? I'm using an BP60NB10 drive, 4K blurays look to be in perfect condition.

I find that the Plex client on tvOS suffers from the occasional stutter. I have better luck with Infuse on AppleTV. Infuse should be able to play videos from your Plex server.

I thought it might be Plex too so I downloaded the MKV to my M1 Pro Mac and played it back with IINA and it was skipping at the exact same point which leads me to believe theres an issue with the rip.

If makemkv didn't say something is wrong nothing is wrong with it

Billycar11 is right. MakeMKV checks the data that is copied from the blu-ray (or 4K UHD) and verifies it is correct using the 'content hash tables' that are on the disc. During the ripping process, if MakeMKV can't get a good copy of the disc, it errors out and no output is written. So, if MakeMKV produces a file, then that file is a good copy of what's on the optical disc.

It is possible, though not likely, that the file was corrupted somehow when it was copied to the NAS or was corrupted while it has been living on the NAS.

I suppose the easiest way to test that theory is to put the optical disc in your drive and let MakeMKV create another rip of it and see if the hiccup exists in the new rip.

I have started to experience similar. Posting as there are some similarities in our set up if I am reading right.

Mac M2 - 2 different external UHD drives. Also playing back via Apple TV 4K latest via Samsung T7 on another M2 Mac.

Started happening in the last month or two. Done hundreds successfully before about Feb / March. Now I can rip / re-rip and get skips or missing frames in different places per rip using either a Pioneer slim or ASUS 5.25 with Vantec interface.

Going to try putting the 5.25 in a Windows workstation to rule out MacOS.