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Subject: Re: Audio fingerprinting (was Re: hacksdmi?)
From: Lincoln Yeoh (lyeohPOP.JARING.MY)
Date: Sun Oct 15 2000 - 02:41:10 CDT


At 02:02 AM 10/14/00 -0400, Geoff Schmidt wrote:
>On the other hand, it only takes a couple of bits to store a
>watermark, and there's huge amounts of redundancy in audio, so the
>hide and seek game could go on for quite a while.

If you only need to write 32 bits into a 120 second long song it doesn't
look too bad. But once you start trying to shove PKI type keys into it,
woohoo. A bit a second at 90db S/N is probably noticeable to the "Golden
Ears" folks out there, so good luck getting 10 bits a sec....

I think Shannon's famous formula will help tell you how much you have to
play with given an acceptable signal level for music. It doesn't tell you
how to do it, but at least it's easy to prove at which point it becomes
very difficult.

As you said audio compression will make things even more difficult.

Cheerio,
Link.