On 2011-12-16, Mark Knecht <[email protected]> wrote:
> On Fri, Dec 16, 2011 at 11:03 AM, Grant Edwards><[email protected]> 
> wrote:
>
>> Correct. If you use dd to copy an encrypted disk, the result will be
>> missing something like 90% of the data.
>>
>>> I have no interest in tearing apart the DVD in any way. It was more
>>> about the idea of a fire causing the loss of maybe $15K-$20K
>>> investment over the years. I can rip all the CDs, keep the ripped
>>> version here to watch on the computer, and store the DVDs elsewhere,
>>> but that elimiates (generally) being able to watch special features
>>> which my wife and kid enjoy.
>>
>> No it doesn't. You can use dvdbackup (or k9copy or ...) to copy the
>> DVDs to the computer and when you play them back you get all the
>> menus and special features and whatnot. If you want you can create
>> ISO images and burn them to dual-layer-DVDs, but you don't need to do
>> that to play them with all the features.

> So for my continued education, if I take an encrypted movie I can use
> program XYZ (Linux or Windows-based...) to create an iso image, but
> that iso image won't, even if it does include all the special
> features, ever be a bit-for-bit copy of the original. It's now
> unencrypted and created anew.

Exactly.  I used to use k9copy, but I got tired of fighting with Qt
dependancies and switched to dvdbackup.  Sometimes I create ISOs and
burn them to DVDs, but usually I just create directory trees and watch
them via a SageTv set-top-box that mounts the directory via NFS.

> It's a completely different way to represent the original data.

Yep.  I'm not aware of any Linux software that can create an encrypted
DVD -- but I've never had a desire to do that, so my lack of knowlege
of such a thing shouldn't be used as an indication of non-existence of
such a thing. :)

> That said, if it's a _complete_ representation of the original then
> the special features are there, and if written to a DVD _might_ work
> in my DVD player,

They've always worked in the DVD players I've tried them in, including
subtitles, special features, multiple audio tracks, etc.  The various
"backup" programs usually have options to pare down what's copied so
that you can do things like copy only the main title with one audio
track (with or without menus, subtitles, etc).  Some of the backup
programs will also re-encode the video to make the end result fit
within a specified size -- for example you can generate a 4.7G ISO
image from a 9GB original.

> assuming the DVD player isn't specifically looking for something that
> was on the original disc such as specifically encrypted blocks of
> data, etc.
>
> Am I getting closer?

Indeed you are.

-- 
Grant Edwards               grant.b.edwards        Yow! How's it going in
                                  at               those MODULAR LOVE UNITS??
                              gmail.com            


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