OK, this has got me scratching my head, hopefully somebody here can shed some light on it for me.

So let's assume I download a video in DVD format, and that it comes with an md5 text file. After it's downloaded, all the files always match the md5's in the list.

Now I want to burn them to DVD. What I'd like to do is use imgtool to build an iso file that I can then burn with DVD Decrypter. So I build the iso with imgtool, then to check, I mount the iso with DAEMON tools. The md5's in the mounted version very rarely match. The smaller files always match, but the larger files, VTS_01_1.VOB and up, often don't. Each time through imgtool usually gives different results, and if I spend all night at it, I can eventually get all md5's to match.

A similar thing also happens to me using nothing but DVD Decrypter. I'll start with a working burned disc, and generate md5's for everything in VIDEO_TS. Then I'll make an iso image with Decrypter. Mount that iso with DAEMON Tools, and again, at least 1 of the .VOB's usually doesn't match.

Now, if I do a straight copy of VIDEO_TS from DVD to my hard drive, md5's will match between the two copies, which I suppose is encouraging. But when I take these files and burn them with Nero, guess what, some of the md5's don't match again.

Interestingly, even if I burn one of these "not quite right" iso images to DVD, the end result is completely playable, and I've never noticed a single glitch. However, it's disconcerting and makes me not want to trade anything for fear of poluting the trade pool. The md5's don't lie. Obviously there was some difference between the original and the copy, and that can't really be good.

I've used md5summer and openssl under cygwin to generate/compare my md5's, with the same results.

So does anybody have any idea why this is happening to me? Has anybody experienced anything similar?

I'm running XP on a 1.4Ghz Athlon with 1G RAM. All my drives are NTFS. I can provide more details if needed.