DVD ISO problem

[Henry Spencer]

On Tue, 10 May 2005, William O'Higgins wrote:
> The disc I am trying to copy is a standard movie DVD...
> I tried dvdbackup as well, but it is not as effective, because the
> resultant copies have had their copy protection stripped off (and then
> they don't play in DVD players reliably) - what I am looking for is a
> bit-for-bit copy (onto a dual layer disc if necessary).  Is this
> possible?  Are there features on a DVD that make this unworkable?

Indeed there are.

Movie DVDs encrypt the video/audio data for copy protection, and there is
a special area of the disk where the players go to find the encryption
keys.  On consumer R and RW disks (whether + or -), that area is all zeros
and not writable (writing to it is physically impossible; the writable
layer in the disks doesn't cover that area).  So making a bit-for-bit copy
onto consumer writable media is impossible, period.  Stripping off the
copy protection is the best you can do.

(I keep saying "consumer" because there's an industry-oriented
writable-DVD technology, whose name I forget, which can write that area... 
but both disks and drives are much more expensive than the consumer ones,
and seldom carried by retail suppliers.)

                                                          Henry Spencer
                                                       henry-lqW1N6Cllo0sV2N9l4h3zg at public.gmane.org

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