Two oddities I've recently noticed

[bpmod]

I have been using ImgBurn for many years now and have found it to be absolutely indispensible for reading and writing optical discs. I use it mostly to rip DVDs to ISO. Since DVDs are usually copy-protected, I have been running AnyDVD in the background. I have ripped hundreds, possibly as many as a thousand or more and the combination has always proved rock-solid.

However, I HATE Windows and recently my Windows installation has been getting less and less usable, so I have been looking at options to rip DVDs under Linux. To that end, I have been spending a lot of time looking at the rips in a hex editor.

All of the files that I have looked at have one byte changed from the DVD to the ISO, at the same offset and by the same amount. I cannot figure out why this byte would be changed or how. It might be something that AnyDVD is doing (in which case this might not be the best place to ask), or it might have something to do with ImgBurn.

I have noticed this in only 4 discs so far. I thought I'd ask befor checking another few dozen or hundred...

The byte in question is part of a 32-bit value in the VIDEO_TS.IFO file (and its corresponding .BUF file) at bytes 12 to 15 of that file. In the discs where I've noticed it, that value has been increased by exactly 1 (that's why it affects only a single byte, rather than all four).

According to this website: http://www.mpucoder.com/DVD/ifo.html, the value represents the last sector of VMG set (last sector of BUP).

Does anybody here have any insight as to why that value is being changed and whether it is being done by ImgBurn or AnyDVD?

The other oddity I noticed, although it affects only one disc that I have found so far, is the ISO of one rip is 32k larger than the DVD that was ripped. When doing a checksum of that ISO against a rip I did under Linux, they of course didn't match. So when I noticed the filesize discrepancy, I truncated the ISO at that point and the checksums matched. It has me baffled! Any ideas?

Thanks

Brian

 

Edited 2 hours ago by bpmod
added link to more info