[vorbis-dev] patents and separate entropy coding

Jack Moffitt jack at icecast.org
Fri Dec 15 12:08:34 PST 2000

> Roger, sorry 'bout that. I am talking about patent claim #US5579430
> which is entitled Digital encoding process and can be found at
> http://www.delphion.com/details?pn=US05579430__

You are talking about patent #US5579430

What you quoted from the patent is NOT a claim, even though it is
similar.  It's just the abstract.  Abstracts tend to be broad.

Clicking on "expand details" and hunting down the page for "Claims"
Gives us:

Under Claim #1, it says "transforming the samples of said acoustical
signal using a transform/filter bank"

Note "transform/filter bank".

Vorbis does not use a filterbank.  This is a specific reference to the
polyphase filterbank stage that is BEFORE teh mdct in Mpeg audio
encoder.  Vorbis does not use this stage, and therefore our audio
encoding process is different.

This patent is broad though.  You could claim it covered many things,
including things like jpeg.  I don't think claim #1 would stand up.
Some of the more specific claims (delphion shows a total of 32 claims).

So now that we all understand how to reference patents and claims, this
discussion should get much more to the meat of any problems :)


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