Re: hacksdmi?

["Bluefish (P.Magnusson)" <11a () GMX NET>]

>       This maybe a silly question but, couldn't they put a watermark into
> the sound by using sounds that we cannot hear? Very high or very low
> frequencies could be used, so could sounds that will be overpowered by the
> watermarked content.

This is one technique that actually is defeated by none-malicious
processing ; it won't survive filters (low-, hi-, bandpass etc). It is
also unlikely to survive many different compression techiques. Given loosy
DA->AD->DA conversion, it probably won't survive that as well. And, if it
is strange short peaks of sounds on a high frequency, it becomes
detectable as well - you can algorithmitcly determin that that there are
suspicious peaks (short waveforms with frequency above hearable limits).

So it's actually the worst kind of watermark ;)

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    eleventh alliance development & security team

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