[PaulHarald]

This is a VERY interesting thread. I use Toast on a Mac and can confirm the same .ifo and .bup changing on some - but just some - DVDs. The guy saying he never had a problem with Toast and his Mac may be right, but if he did a full "compare" (utilities menu in Toast) or did md5 checksum files of the original and the copy, he might find some files changing.

I posted this observation to the official Roxio (makers of Toast) forums and got these replies:

<quote>

Well, I can tell you that Toast does have to modify the IFO files so that the Offsets are correct.

...

I'm just guessing here and I haven't tried it myself, but I think this could be happening.

If someone writes a Video_TS folder directly to the HD from an authoring application, or an application that doesn't do it correctly the offsets could be off. When Toast writes the VIDEO_TS folder the offsets get corrected and the resulting VIDEO_TS folder would fail to verify and compare.

If the VIDEO_TS folder was first burned to a disc, then that VIDEO_TS folder was taken from the disc and saved to the hard drive, the offsets should be correct already. In this case, when the VIDEO_TS folder got burned in Toast, no changes would be needed and the disc would verify.

When burning DVD Dual Layer in Toast, the IFO also needs to be updated to set the break point correctly.

<end quote>

So there you go. Someone suggesting running discs through Nero to "rectify" them - well that might be it and maybe Toast does the exact same thing. Toast is the gold standard app for DVD burning on the Mac. Always trusted it and never had problems before md5 checking came along :-)

Actually, when using MacTheRipper (Mac ripping app) to rip a DVD, then burning, the .ifo and .bup files ALWAYS change, same thing if I save as disc image from Toast so it's not the burning it's the file handling. This may be an example of what the Roxio guys said about certain authoring apps. IMO Ripping should never be performed on region free unencrypted DVDs like the ones we are trading, they should just be copied.

This is a difficult problem we're discussing here, and I'm just a user, not an expert. I have even seen Toast being determined to change .VOB files (again and again when repeated on different Macs and after re-downloading) with some very few torrented DVDs on EZT so I wonder what that's all about. They play fine, but md5 checksums are of course altered, and people who doesn't check if it's a perfect clone won't know but it isn't.

I wish someone would get to the bottom of this one!

Cheers,

PaulHarald