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".

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