Apart from the position of the layer break, what other information is contained in an MDS file?

[FlimsyFeet]

Question is as topic title. I ask only out of interest really, because recently I noticed that 2 MDS files that I expected to be the same were different:

 

1. create an ISO/MDS in build mode from VIDEO_TS folder on the hard drive

2. burn this image to DVD+R DL

3. create ISO/MDS image file from this disc

 

A CRC32 hash shows that the ISO's created in step 1 and step 3 are idewntical, but the MDS files are different, I assume the layer break position has not been changed, so I just wondered where the difference comes from?

[LIGHTNING UK!]

Lots of other stuff about the disc but it's really only used when mounting - or at least ImgBurn doesn't use it.