A computer components & hardware forum. HardwareBanter

If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below.

Go Back   Home » HardwareBanter forum » General Hardware & Peripherals » Cdr
Site Map Home Register Authors List Search Today's Posts Mark Forums Read Web Partners

Is decryption/compression still needed to copy a DVD movie using a dual-layer burner?



 
 
Thread Tools Display Modes
  #1  
Old November 30th 04, 04:08 AM
Joe
external usenet poster
 
Posts: n/a
Default Is decryption/compression still needed to copy a DVD movie using a dual-layer burner?

Correct me if I'm wrong here.

Once upon a time, consumer DVD burners were limited to burning
single-layer DVD's with a capacity of around 5 gb per disk. But
(all?) commercial movie DVD's come on dual-layer disks with a capacity
of up to 9 gb.

So it was never possible for the home computer user to make an exact
copy of a DVD movie in a manner similar to making an exact copy of a
music CD. Instead, the movie had to be decoded (de-crypted) and then
re-compressed (with arguably some loss of detail or resolution) in
order to fit onto a 5 gb blank media. But with the copywrite or
patent or licensing issues surrounding the decoding/decryption
process, there really was no "legal" source for the decoding software
(DVD X-copy being an exception that was eventually killed by the
courts). There are, however, public sources for free-ware decryption
and compression software.

Now then, with the availability of dual-layer DVD burners and
dual-layer media, it should therefore be possible to make a straight
copy of the files on a movie DVD and burn them onto a blank dual-layer
DVD disk and end up with a copy of the movie without the need to seek
out and use decryption/re-compression software.

Is there something I'm missing here, like perhaps some other form of
copy protection or hidden files on the movie DVD that can't be simply
copied to the burn-able disk?
  #4  
Old November 30th 04, 06:43 AM
Dan G
external usenet poster
 
Posts: n/a
Default

DVDDecryptor will make an ISO and burn it to a DL disc very nicely, placing
the layer break in the same place as well.


"Joe" wrote in message
om...
Correct me if I'm wrong here.

Once upon a time, consumer DVD burners were limited to burning
single-layer DVD's with a capacity of around 5 gb per disk. But
(all?) commercial movie DVD's come on dual-layer disks with a capacity
of up to 9 gb.

So it was never possible for the home computer user to make an exact
copy of a DVD movie in a manner similar to making an exact copy of a
music CD. Instead, the movie had to be decoded (de-crypted) and then
re-compressed (with arguably some loss of detail or resolution) in
order to fit onto a 5 gb blank media. But with the copywrite or
patent or licensing issues surrounding the decoding/decryption
process, there really was no "legal" source for the decoding software
(DVD X-copy being an exception that was eventually killed by the
courts). There are, however, public sources for free-ware decryption
and compression software.

Now then, with the availability of dual-layer DVD burners and
dual-layer media, it should therefore be possible to make a straight
copy of the files on a movie DVD and burn them onto a blank dual-layer
DVD disk and end up with a copy of the movie without the need to seek
out and use decryption/re-compression software.

Is there something I'm missing here, like perhaps some other form of
copy protection or hidden files on the movie DVD that can't be simply
copied to the burn-able disk?



  #5  
Old November 30th 04, 11:11 AM
Lordy
external usenet poster
 
Posts: n/a
Default

" wrote in
:

Id like to see a site comparing a slightly compressed version to the
original ,


This is one for a long film ...

http://www.dvd.box.sk/articles8.php
http://www.dvd.box.sk/articles12.php

--
Lordy
  #6  
Old November 30th 04, 09:11 PM
Jamco
external usenet poster
 
Posts: n/a
Default

right now a blank dual layer disc costs up to $15 each...whats the point?
If your going to spend $15 for the disc, why not just buy the original?

"Dan G" wrote in message
...
DVDDecryptor will make an ISO and burn it to a DL disc very nicely,
placing
the layer break in the same place as well.


"Joe" wrote in message
om...
Correct me if I'm wrong here.

Once upon a time, consumer DVD burners were limited to burning
single-layer DVD's with a capacity of around 5 gb per disk. But
(all?) commercial movie DVD's come on dual-layer disks with a capacity
of up to 9 gb.

So it was never possible for the home computer user to make an exact
copy of a DVD movie in a manner similar to making an exact copy of a
music CD. Instead, the movie had to be decoded (de-crypted) and then
re-compressed (with arguably some loss of detail or resolution) in
order to fit onto a 5 gb blank media. But with the copywrite or
patent or licensing issues surrounding the decoding/decryption
process, there really was no "legal" source for the decoding software
(DVD X-copy being an exception that was eventually killed by the
courts). There are, however, public sources for free-ware decryption
and compression software.

Now then, with the availability of dual-layer DVD burners and
dual-layer media, it should therefore be possible to make a straight
copy of the files on a movie DVD and burn them onto a blank dual-layer
DVD disk and end up with a copy of the movie without the need to seek
out and use decryption/re-compression software.

Is there something I'm missing here, like perhaps some other form of
copy protection or hidden files on the movie DVD that can't be simply
copied to the burn-able disk?





  #7  
Old December 1st 04, 04:05 PM
Bill Vermillion
external usenet poster
 
Posts: n/a
Default

In article Pt4rd.210108$df2.72@edtnps89, Jamco wrote:
right now a blank dual layer disc costs up to $15 each...whats the point?
If your going to spend $15 for the disc, why not just buy the original?


Last month I saw them priced at about $10 each.

Two days ago the same place had them at $9 each.

They are getting cheaper but at about 40 cents for quality disks
[if you know where too look and follow sales] makes them far
cheaper.


"Dan G" wrote in message
...
DVDDecryptor will make an ISO and burn it to a DL disc very nicely,
placing
the layer break in the same place as well.


"Joe" wrote in message
om...
Correct me if I'm wrong here.

Once upon a time, consumer DVD burners were limited to burning
single-layer DVD's with a capacity of around 5 gb per disk. But
(all?) commercial movie DVD's come on dual-layer disks with a capacity
of up to 9 gb.

So it was never possible for the home computer user to make an exact
copy of a DVD movie in a manner similar to making an exact copy of a
music CD. Instead, the movie had to be decoded (de-crypted) and then
re-compressed (with arguably some loss of detail or resolution) in
order to fit onto a 5 gb blank media. But with the copywrite or
patent or licensing issues surrounding the decoding/decryption
process, there really was no "legal" source for the decoding software
(DVD X-copy being an exception that was eventually killed by the
courts). There are, however, public sources for free-ware decryption
and compression software.

Now then, with the availability of dual-layer DVD burners and
dual-layer media, it should therefore be possible to make a straight
copy of the files on a movie DVD and burn them onto a blank dual-layer
DVD disk and end up with a copy of the movie without the need to seek
out and use decryption/re-compression software.

Is there something I'm missing here, like perhaps some other form of
copy protection or hidden files on the movie DVD that can't be simply
copied to the burn-able disk?







--
Bill Vermillion - bv @ wjv . com
  #8  
Old December 2nd 04, 03:01 AM
Joe
external usenet poster
 
Posts: n/a
Default

MCheu wrote in message

No compression, but you still need decryption. The region of the disc
where the encryption key is stored on a pressed disc isn't writeable
on a writeable disc.


So what you're saying is that even though I can replicate all of the
files on a movie CD by doing a straight copy to a blank dual-layer
disk, there is still something on the movie CD that can't be copied or
replicated on the destination disk.

That something being an attribute or some other element of data such
as an "encryption key" (that is not stored as file itself?).

If so, then the process of decryption is still needed only to generate
a non-encrypted version that can then be burned to a dual-layer disk
(yes?).

Does that also mean that I can't burn an encrypted version of my own
home movies to a DVD? (in other words you can't create your own DVD
with the same copy-proof "strength" as a commercial movie CD). ?

it is IMPOSSIBLE to write to that region on a writeable disc. That's
by design, and even if you can get around that in the burners, there's
still the matter of the discs themselves.


In other words, you're saying that a blank DVD disk is not necessarily
blank, but that it will always retain some information that can't be
altered or over-written by a DVD burner drive, and that's why you
can't simply dump the contents of a commercial movie DVD over to a
blank dual-layer disk and expect a DVD player to play it.

Does that also mean that I can't copy the contents of a commercial
movie DVD to my hard drive and play it from the hard drive as-is ?
  #9  
Old December 2nd 04, 03:27 PM
MCheu
external usenet poster
 
Posts: n/a
Default

On 1 Dec 2004 18:01:00 -0800, (Joe) wrote:

MCheu wrote in message

No compression, but you still need decryption. The region of the disc
where the encryption key is stored on a pressed disc isn't writeable
on a writeable disc.


So what you're saying is that even though I can replicate all of the
files on a movie CD by doing a straight copy to a blank dual-layer
disk, there is still something on the movie CD that can't be copied or
replicated on the destination disk.


Not a Movie CD, no, as your original question was about DVDs, not CDs.
VCD (Video CD), SVCD (SuperVideo CD), XVCD (Xtended Video CD) are not
usually encrypted.


That something being an attribute or some other element of data such
as an "encryption key" (that is not stored as file itself?).

If so, then the process of decryption is still needed only to generate
a non-encrypted version that can then be burned to a dual-layer disk
(yes?).


That is correct. Don't get me wrong, you can certainly burn those
encrypted files over to a blank DL DVD disc. The files would just be
unplayable as they're scrambled (encrypted), you need the key to
unlock them, which on the original is stored in that region which is
unwriteable on ...erm... writeables. That was a requirement by the
movie industry when the standards were being formed.


Does that also mean that I can't burn an encrypted version of my own
home movies to a DVD? (in other words you can't create your own DVD
with the same copy-proof "strength" as a commercial movie CD). ?


Well, you typically wouldn't encrypt your home movies.

If you really, really wanted to encrypt them, you can certainly do it,
just as with any data. In fact you can encrypt them with a much
stronger level of protection than the commercial movies, as CSS
encryption is relatively weak compared to what's commonly used for
commercial transactions or even private emails. Of course, this
wouldn't prevent anyone from making a copy, it just makes it
unplayable without the decryption software and the key. I can't
really see any reason for someone encrypting their home videos in this
way unless they were really embarrassing, or they're home video of the
CIA/NSA Christmas party :-) Anyways, I'm probably overcomplicating
things in this paragraph, so you can probably just ignore this one if
it sounds like too much.

If you mean to encrypt them the same way as a commercial DVD using one
of the DVD standard keys, and encoding the code onto the disc, then
no. As I said, that region of the disc where the key is normally
stored is mostly not writeable. Can't be done with a writeable disc.

If you really wanted to produce something like a commercial DVD, there
are shops that will press small DVD runs. It'd still be a lot of
discs, as minimum runs tend to be pretty high (we're talking 1000+
discs here). If you want them encrypted with CSS, some small
publishers that are licensed to do CSS encryption can do it, but the
shop would likely have to charge you extra as there are licensing fees
involved with using CSS. Don't ask me how much this would cost, I've
never looked into it too deeply. I would imagine it to be expensive
though, and likely too expensive and too much trouble for a small run
of 30-200 wedding video DVDs for the family.


it is IMPOSSIBLE to write to that region on a writeable disc. That's
by design, and even if you can get around that in the burners, there's
still the matter of the discs themselves.


In other words, you're saying that a blank DVD disk is not necessarily
blank, but that it will always retain some information that can't be
altered or over-written by a DVD burner drive, and that's why you
can't simply dump the contents of a commercial movie DVD over to a
blank dual-layer disk and expect a DVD player to play it.


I guess so. It's more or less true. It's not so much that there *IS*
information there in those regions. The headers are supposed to
contain information about the media type, the manufacturer, the dye
type, the rated speeds, etc, but some of those areas could just be
left blank. It's not so much that the discs have that information
already in place (though it is usually there), but that these regions
are declared off limits by design. Even if those regions were blank
(which is very unlikely) the burners wouldn't be able to burn to those
areas. You can't hack past it, because this limitation is built into
the discs and the burners by design to slow you down when you try to
copy a disc.

Does that also mean that I can't copy the contents of a commercial
movie DVD to my hard drive and play it from the hard drive as-is ?


Yes. You can certainly pull the files straight off the disc, but the
encrypted files themselves won't be playable.
---------------------------------------------

MCheu
  #10  
Old December 3rd 04, 12:15 AM
Octavian
external usenet poster
 
Posts: n/a
Default

I wonder ...

The un-writable portion of an encrypted movie DVD (the part that contains
the encryption keys) is readable, right?

If so, can that data be read by the host computer?

If so, then ... question: does the decryption in a standard set-top player
(or PC-based DVD player software) perform the decryption in the host
computer?

If both of those questions are YES ... then one could produce a DVD copy
without doing any decryption! Instead, you could copy the data (vob, ifo,
etc.) files directly to another DVD, as a standard ISO or UDF file system.

Now, suppose you were to develop special software that wrote that DVD
ISO/UDF file system in a "special" way. Instead of creating a 4.500 GB file
system, create one that's only, say, 4.499 GB. Leave the last 1 MB of
storage untouched by the file system. Copy the entire set of original DVD
files to this perfectly-normal 4.499 GB file system.

Then, copy the encryption codes from the original DVD into that last,
reserved MB of space.

Now, develop special software (a special DVD player program) that reads the
encryption information from that last MB, and reads the vob files as usual
from the standard file system. Perform the decryption of the vob files using
the (perfectly correct) encryption keys that you read from that last MB.

All of this assumes that:
1. The encryption keys are readable by the host computer.
2. The encryption takes place on the host, not in the
DVD drive.
3. You have the gumption to write special DVD burner
software that will create the special file system
with the "extra/unused" MB.
4. You have the will to write a special DVD player
program to recognize the specially-formatted DVD.

Of course, this applies to PC-based playback only ... unless you know how to
hack the O/S of a set-top player.

And, of course, I wonder if all of this produces a real benefit. We already
have the means to crack the encryption. I just wonder ... If my idea, above,
could be made to work, then would the time needed to do make a copy using
this copy-unencrypted-and-burn method be faster than the existing
copy-decrypt-and-burn method?

"MCheu" wrote in message
...
On 1 Dec 2004 18:01:00 -0800, (Joe) wrote:



 




Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Unable to make backup copy pmf Cdr 1 August 16th 04 02:22 AM
my new mobo o/c's great rockerrock Overclocking AMD Processors 9 June 30th 04 08:17 PM
Can't copy Microsoft CDs but I've done it before with Plex and ECDC?Using Liteon and Nero smh Cdr 15 December 9th 03 12:24 AM
Failed to copy a "copy control" CD David K. Cdr 2 July 18th 03 10:13 PM


All times are GMT +1. The time now is 02:39 AM.


Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright ©2004-2024 HardwareBanter.
The comments are property of their posters.