www.makemkv.com

Hi, I've been experimenting with the trial version of MakeMKV (1.9.. I've noticed my BluRay rips have different checksums if I do a MD5/SHA-1 hash.
I've tried different BluRay drives, different destination source drives, TV and movie discs, PC and Mac versions of the software. No matter what I've tried, I can not produce 2 identical MKV files from the same source disc.

I came across this thread after searching on Google, which suggests this was an issue in prior versions of MakeMKV but should be fixed now
http://www.makemkv.com/forum2/viewtopic.php?f=1&t=3660

Any advice?

Each chapter requires a unique unique ID, otherwise if you try to append the files MKVMerge will mess up your chapters by design.

I don't know if MakeMKV assigns unique unique IDs to attachments, but that could be a consideration too. If a chapter or attachment UID happens to fit in a smaller number of bytes, some pointer sizes could be affected to.

There's also the UTC Date in the segment header and possibly other things I can't think of at the moment.

So basically there's ZERO chance of two different rips producing the same hash. That thread you linked to is about the streams themselves. Try using MKVExtract on the tracks and getting hashes from those. If they add up then this issue is null and void.

MakeMKV or any other tool aimed to create an .mkv file from an optical disc are not supposed to generate the exact same file every time.

Like ndjamena said, .mkv files have some extra information to the video/audio/subtitle. Let's just observe the file I just created with MakeMKV with ffmpeg.
Did you notice the version number and the creation time? Yes, that's the reason every time you create an archive with MakeMKV, the checksum varies.

If you want a precise dump of your disc, without anything appended, you should consider a disc-level archive, which means you dump your disc with tools like UltraISO/IsoBuster/CloneCD and output as bin/cue. Search the Internet for more information.

ndjamena wrote:Each chapter requires a unique unique ID, otherwise if you try to append the files MKVMerge will mess up your chapters by design.

I don't know if MakeMKV assigns unique unique IDs to attachments, but that could be a consideration too. If a chapter or attachment UID happens to fit in a smaller number of bytes, some pointer sizes could be affected to.

There's also the UTC Date in the segment header and possibly other things I can't think of at the moment.

So basically there's ZERO chance of two different rips producing the same hash. That thread you linked to is about the streams themselves. Try using MKVExtract on the tracks and getting hashes from those. If they add up then this issue is null and void.

Thanks for the info. I did as as you recommended and compared the video track using MKVExtract. The checksums match.
It would be nice to add an option to MakeMKV to turn off timestamps/metadate (if possible).
Thanks for your help everyone.

Hi, are information like encoder or date necessary that the file will play proparly? When not, could someone add an option to remove them, I dont think they are useful.

They're likely not essential. You can use a program called MKVToolnix to download it (Google it - it's the top result).