Create .mkv file directly from disc vs from protected backup

[frodobagginz]

Hopefully a quick question. If I rip a video to .mkv directly from the disc, and then rip the same video with the exact same selections (audio, subtitle, etc.) from a backup (created with MakeMKV), the two resulting .mkv files are not identical. They are the same exact size, but produce different sha256 hashes. Why is this?

[Woodstock]

The header of the MKV file includes the date/time that it was created. Rip at 2 different times, and the hash will be different, because the header is different.

[frodobagginz]

Aha, that makes perfect sense. Thanks for the quick reply!

What I was attempting to confirm myself is that an .mkv created from a protected backup is identical to an .mkv created directly from disc. Is it safe to assume this is the case? And if so, does it matter if the backup is protected or not?

[Woodstock]

It SHOULD be the case, but the only way to really verify it is to extract the different tracks and compare them individually. That is a pain.

Personally, I just go with what Mike told us a few years ago.