Re: [ILUG] jpeg patented...

From: David Neary (dneary at domain wanadoo.fr)
Date: Mon 22 Jul 2002 - 09:32:59 IST


Ronan Waide wrote:
> Having skimmed over the patent, it appears to be describing a sort of
> image compression algorithm which gels more or less with the JPEG
> mechanism. Since I don't quite understand how jpeg works (it's hard
> math, and I'm just a dumb comp. eng.)

It's not hard math - jpeg is a straight block-based DCT with
quantisation - which is about the oldest image compression
algorithm out there, and I think certainly predates 1986. So I
really have no idea what they claim they've patented - doin DCT
on 8x8 blocks of an image, quantising the resulting coefficients,
or DCT in general? I'm extremely skeptical about this whole
story...

> I don't know how exactly it
> matches up to JPEG. I'm more curious as to whether it covers MPEG,
> because it /is/ described in the context of video streams rather than
> stills, and I had a vague impression that the MPEG and JPEG
> compression techniques were similar. One of the patents it references
> also seems to hint at MPEG.

MPEG 1, 2, 4 or 7? They're all very different compression
algorithms.

Anyway, here's to ogg, and hopefully the future mpeg4-standard
compression algorithm the project comes up with (fingers
crossed). And I wouldn't worry about the jpeg thing - in addition
the patent runs out next year, and I would suggest that having
failed to protect their IP for 15 years, as (iirc) is their
responsibility, their claim would probably never hold up in
court.

Cheers,
Dave.

-- 
       David Neary,
    Marseille, France
  E-Mail: bolsh at domain gimp.org


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