 |
|
|
|
|
|
| |
| |
|
|
|
|
| |
| |
|
|
>> Interesting. So the film actually ends a different way depending on
>> which player you play it with?
>>
>> I bet that'll be popular...
>
> LOL, I suspect they can do it slightly more subtly than that! They only
> need to make some tiny changes to some of the pixels to be detectable.
> In theory they could do what you suggest though, would be fun :-)
Well, the article states that it's supposed to resist somebody pointing
a video camera at their TV screen, so a 1-pixel alteration won't do.
What I suppose they might do is have maybe a 1-frame difference in how
long a given scene is. Like, on some disks the shot of the ocean is 1362
frames long, and on others it lasts for 1366 frames. The difference
should be reliably detectable no matter how you film it.
Still, it seems like a hell of a lot of work considering that it doesn't
actually stop illegal copying, it just makes it hypothetically possible
to find out who did the illegal copying...
Post a reply to this message
|
|
| |
| |
|
|
|
|
| |
| |
|
|
scott wrote:
> BitTorrent, they can tell exactly which player it was ripped from.
With the understnading that a "player" in this context means "model number"
at least in the hardware players. I.e., they can tell it got ripped by a
Sony XYZ-1230 brand blu-ray player, not Joe's blu-ray player.
The idea is to identify it enough to black list the leaked keys, not to
catch the person who distributed the movie.
--
Darren New, San Diego CA, USA (PST)
I ordered stamps from Zazzle that read "Place Stamp Here".
Post a reply to this message
|
|
| |
| |
|
|
|
|
| |
| |
|
|
Invisible wrote:
> Well, the article states that it's supposed to resist somebody pointing
> a video camera at their TV screen, so a 1-pixel alteration won't do.
Probably different watermarks encoded, without actually looking visibly
different in a way you could tell. Otherwise, someone might just rip it
twice and change the file to use (say) 1364 frames of ocian.
--
Darren New, San Diego CA, USA (PST)
I ordered stamps from Zazzle that read "Place Stamp Here".
Post a reply to this message
|
|
| |
| |
|
|
|
|
| |
| |
|
|
>> Well, the article states that it's supposed to resist somebody
>> pointing a video camera at their TV screen, so a 1-pixel alteration
>> won't do.
>
> Probably different watermarks encoded, without actually looking visibly
> different in a way you could tell. Otherwise, someone might just rip it
> twice and change the file to use (say) 1364 frames of ocian.
Well, to lots of people digital watermarking is the Holy Grail of
digital technology, the thing that will finally stop the pirates.
Trouble is... it's extremely hard.
If the watermark is encoded in a way that's perceptually
insignificant... well guess what lossy codecs are specifically designed
to do? Yes, that's right: *remove* perceptually insignificant information!
I'm thinking things like small timing differences would be too subtle to
notice, but significant enough for encoding to not screw them up. And
you could try to correct it yourself, but you'd have to know exactly
which bits of timing are varied in order to know what to change...
--
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*
Post a reply to this message
|
|
| |
| |
|
|
|
|
| |
| |
|
|
>> BitTorrent, they can tell exactly which player it was ripped from.
>
> With the understnading that a "player" in this context means "model
> number" at least in the hardware players. I.e., they can tell it got
> ripped by a Sony XYZ-1230 brand blu-ray player, not Joe's blu-ray player.
>
> The idea is to identify it enough to black list the leaked keys, not to
> catch the person who distributed the movie.
The article suggests that the system *is* supposed to be able to narrow
it down to a specific machine or possibly a small number of such
machines, not just a specific model.
Of course, it depends on whether the makers bother to fit each player
with semi-unique keys or not... One commenter pointed out that hardware
manufacturers have no vested interest in making DRM work. Only studios do.
--
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*
Post a reply to this message
|
|
| |
| |
|
|
|
|
| |
| |
|
|
Orchid XP v8 wrote:
> Trouble is... it's extremely hard.
Certainly.
> If the watermark is encoded in a way that's perceptually
> insignificant... well guess what lossy codecs are specifically designed
> to do? Yes, that's right: *remove* perceptually insignificant information!
Well, you can spread it across lots of media, a few bits at a time. Xerox
had a mechanism where you could vary the spacing between words in a
document, and encode maybe a couple dozen bits per page of a document, for
example.
But yes, it's difficult. Anything else is open to fairly simple subversion,
tho.
> I'm thinking things like small timing differences would be too subtle to
> notice, but significant enough for encoding to not screw them up.
Could be, until you convert PAL to NTSC. :-) What you'd want is to have
something where it's difficult without the key to even know where the data
is encoded.
> you could try to correct it yourself, but you'd have to know exactly
> which bits of timing are varied in order to know what to change...
But you have the different pieces all on the disk. All you need is the keys
from two different players and you can tell what's different.
--
Darren New, San Diego CA, USA (PST)
I ordered stamps from Zazzle that read "Place Stamp Here".
Post a reply to this message
|
|
| |
| |
|
|
|
|
| |
| |
|
|
Orchid XP v8 wrote:
> The article suggests that the system *is* supposed to be able to narrow
> it down to a specific machine or possibly a small number of such
> machines, not just a specific model.
No, that's what I'm saying. "Player" in *this* context means a set of keys
(obviously). Software players can each get a set of keys from the
manufacturer when you install the machine. But people don't, in general,
program a unique key into each hardware player.
--
Darren New, San Diego CA, USA (PST)
I ordered stamps from Zazzle that read "Place Stamp Here".
Post a reply to this message
|
|
| |
| |
|
|
|
|
| |
| |
|
|
On Wed, 14 Oct 2009 09:22:57 +0100, Invisible wrote:
> Now I'm thinking... it appears to be a standard Data Matrix barcode, so
> if I could figure out WTF the data encoded in it is, I could print as
> many of them as I like, without a fee...
Until you got caught, that is, and fined/put in jail for fraud.... ;-)
Jim
Post a reply to this message
|
|
| |
| |
|
|
|
|
| |
| |
|
|
On Wed, 14 Oct 2009 17:17:25 +0200, scott wrote:
>> Interesting. So the film actually ends a different way depending on
>> which player you play it with?
>>
>> I bet that'll be popular...
>
> LOL, I suspect they can do it slightly more subtly than that! They only
> need to make some tiny changes to some of the pixels to be detectable.
> In theory they could do what you suggest though, would be fun :-)
Probably a form of steganography, at a guess.
Jim
Post a reply to this message
|
|
| |
| |
|
|
|
|
| |
| |
|
|
Darren New schrieb:
> Orchid XP v8 wrote:
>> The article suggests that the system *is* supposed to be able to
>> narrow it down to a specific machine or possibly a small number of
>> such machines, not just a specific model.
>
> No, that's what I'm saying. "Player" in *this* context means a set of
> keys (obviously).
What's obvious about that?
Hardware players are likely to have a Flash ROM or EEPROM anyway, so
it's no technical problem to equip each individual player with a unique key.
And as for motivating manufacturers to do that, it might be a
requirement of the license agreement they had to sign to implement
BlueRay technology in the first place.
Software players, OTOH, typically seem to share a common Device Key for
all installations of a particular player version.
At least that's what I read between the lines of the article.
Post a reply to this message
|
|
| |
| |
|
|
|
|
| |
