Re: [codec] Authors and disclosures, regarding Last Call: <draft-ietf-codec-opus-12.txt>

"Kevin P. Fleming" <kpfleming@digium.com> Wed, 02 May 2012 12:44 UTC

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Date: Wed, 02 May 2012 07:44:37 -0500
From: "Kevin P. Fleming" <kpfleming@digium.com>
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Subject: Re: [codec] Authors and disclosures, regarding Last Call: <draft-ietf-codec-opus-12.txt>
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On 05/01/2012 07:16 PM, Jean-Marc Valin wrote:
> On 05/01/2012 03:33 PM, Joe Baker wrote:
>> >  Can the authors of the draft please indicate when the major components
>> >  of the codec were first offered to the public, in any form, so we can
>> >  better gauge the risk of substantial components being covered by
>> >  undisclosed applications?
> Back when we had the first codec BoF (Jul 2009, Stockholm), both SILK
> and CELT were already being deployed, and though they were further
> modified after that point, the "core technology" hasn't changed that
> much. As far as I can tell, SILK was "first offered to the public",
> early 2009
> (http://www.skypejournal.com/2009/02/silk-skype-new-audio-codec-sets-new.html),
> while CELT was first released late 2007. Since January 2011, the CELT
> layer has been completely frozen and the SILK layer only got minor fixes.

While it's true that SILK was available at that time, it was only 
available in binary form embedded inside products delivered by Skype, 
and those products heavily obscure and encrypt their behavior. It seems 
unlikely that anyone who had IPR in any of its methods would have been 
able to determine that SILK was potentially infringing before its source 
code was made available. I would consider the 'first public disclosure' 
date to be the first time the source code was published.

-- 
Kevin P. Fleming
Digium, Inc. | Director of Software Technologies
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