www.makemkv.com

Hey,

I recently ripped a UHD film which completed ok but when I went back and did a spot check on the video I noticed at 13 mins there was a visual break up of the image.

So I decided to re rip the disc and this time round it worked ok.

My question is I guess is there any kind of error checking which takes place? This is the first visual anomaly I’ve noticed but it’s concerning as I’ve ripped most of my collection and I don’t fancy re ripping all those discs if there are issues.

Regular blu-rays and 4K UHD discs contain something called the content hash table. The purpose of the content hash table is to provide data that the player or in this case MakeMKV can use to verify that the content read off the disc is correct. Consequently, as a general rule of thumb, if MakeMKV produces a file, it should be an exact 1:1 copy of the data from the disc. When MakeMKV encounters an error it can't recover from, it spits out an error and deletes the output.

The short answer is, your rips should be clean.

I can only speculate about what might've occurred with the file with the visual anomaly. UHD files are pretty big. An error in the file might've been introduced into the file after it was ripped. I seem to recall one user on this forum a couple years ago who was occasionally getting a file that had a problem and I think he traced it down to a bad USB chipset controller on his motherboard. He bought a cheap card with USB ports, plugged his drives in there and the problem went away.

I think there are many equally unlikely things that might happen to corrupt a file.

Rip it to another drive/destination 'diff' it and if it still glitches you know it's you for sure.