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From: Craig Milo Rogers <rogers@isi.edu>
To: QuantumG <qg@biodome.org>
Cc: linux-kernel@vger.kernel.org
Subject: Re: reverse engineering pwcx
Date: Fri, 27 Aug 2004 20:35:52 -0700	[thread overview]
Message-ID: <20040828033552.GN24018@isi.edu> (raw)
In-Reply-To: <412FF888.8090307@biodome.org>

On 04.08.28, QuantumG wrote:
> Craig Milo Rogers wrote:
> 
> >	Hmmm... a poster on Slashdot claims that entropy measurements
> >imply that the pwcx code is interpolating rather that truly
> >decompressing.  Again, that's integer math and table lookups.
> > 
> >
> 
> http://www.amazon.com/exec/obidos/tg/detail/-/B00005R098/102-7619892-0201738?v=glance
> 
> claims that the Logitech Quickcam Pro 3000 is a "True 640 x 480 
> resolution video capture" which is now clearly false.

	If the "now clearly false" is meant to be a consequence of the
entropy measurements poster I referred to, I wouldn't jump the gun.
On reflection, it's entirely natural for a decompressed stream to
examine less entropy than the corresponding compressed stream!

					Craig Milo Rogers

  reply	other threads:[~2004-08-28  3:36 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2004-08-28  0:52 reverse engineering pwcx QuantumG
     [not found] ` <20040828012055.GL24018@isi.edu>
     [not found]   ` <20040828014931.GM24018@isi.edu>
2004-08-28  3:14     ` QuantumG
2004-08-28  3:35       ` Craig Milo Rogers [this message]
2004-08-28  3:49         ` Lee Revell
2004-08-28 12:23           ` Vojtech Pavlik
2004-08-28 19:20             ` Chris Meadors
2004-08-28  3:57         ` QuantumG
2004-08-28 12:07       ` Vojtech Pavlik
2004-08-28  6:47 ` Clem Taylor
2004-08-28 12:23   ` Wouter Van Hemel
  -- strict thread matches above, loose matches on Subject: below --
2004-08-28 16:17 Albert Cahalan
2004-08-28 16:25 ` Lee Revell
2004-08-28 16:56   ` Albert Cahalan
2004-08-28 17:11     ` Lee Revell
2004-08-28 18:05       ` Vojtech Pavlik
2004-08-28 17:53   ` Joel Jaeggli
2004-08-28 18:04     ` Lee Revell
2004-08-28 18:08       ` Lee Revell
2004-08-29 21:04 ` Helge Hafting
2004-08-30  7:42   ` Paul Jakma
2004-08-30 12:52     ` Albert Cahalan
2004-08-30 20:23       ` dulle

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