Yes, the parenthesis in the term “(17-year)” in the statement “H.261 was finalized in 1989, outside the (17-year) patent window. Key tool strategies and prior art were already established in that era” is a shorthand for a longer explanation.

Your http://www.kuro5hin.org/story/2008/7/18/232618/312 contains much useful info, highly recommended to anyone looking into this.

As you correctly point out, US patent law changed in the mid 1990s. The US participated in the Uruguay Round in 1994, and the Agreement on Trade Related Aspects of Intellectual Property Rights (TRIPS) precipitated a change in term as of June 8, 1995 for patents filed before that date: from 17 years from issuance to the longer of either 17 years from issuance or 20 years from first US-recognized filing.

http://www.uspto.gov/web/offices/pac/mpep/documents/2700_2701.htm#sect2701

So which term (17 or 20 years) depends on the length of the filing period for a particular patent, which could be more or less than 3 years, as well as what specific filing counts as the first filing.

So some patents have interesting life-extension aspects — it is even conceivable for a patent to be considered still in effect in the US even though it was originally filed, and expired, in another country longer than 20 years ago.

For example consider US 4,970,590, listed in the MPEG Systems patent portfolio list at http://www.mpegla.com/m2s/m2s-att1.pdf. In that document MPEG-LA classifies that patent’s Italian counterpart IT 0624983 as “Expired December 21, 2008″, and this foreign filing date (12/21/1988) is reflected in the US patent “Foreign Application Priority” (see http://www.google.com/patents?id=0aghAAAAEBAJ&printsec=abstract&zoom=4&dq=4,970,590). But MPEG-LA as of January 8, 2009 did not list the US patent as expired. If one were to use the US filing date, this patent still has some 11ish months of validity in the US even though it expired in Italy last December.

US Filing date 12/21/1989 + 20 years = 12/21/2009
US Issue date 11/13/1990 + 17 years = 11/13/2007
Foreign application priority date: 12/21/1988 + 20 years = 12/21/2008

Also MPEG LA calculated Alcatel/Lucent MPEG Visual patent US 4,833,543 “Expired December 23, 2006″

US Filing Date: December 24, 1986
Issue Date: May 23, 1989
Foreign application priority date: Jan 24, 1986 [BE]

But in that case MPEG-LA lists the foreign patents as expiring a bit later (“Expired January 20, 2007″)

http://www.mpegla.com/m2/m2-att1.pdf

Of course, calculating expiration dates of patents is only part of the methodology of note. Essentiality determinations under the procedures of US Department of Justice letters in themselves bring rise to consideration of misdirection and the engendered “myth of essentiality” (how did that rabbit get in that hat in the first place?) — and other aspects of prior art.

You are on to a key insight — many digital media technologies, and even whole standards, have been around for many years and are moving out of the patent window, much like “generic” drugs in the pharmaceutical industry. Similarly, many things that pass as “recent innovation” may indeed be obvious spins on old ideas, or actually quite old themselves (consider for example when the mathematics of DCTs, the foundation of most modern codecs in the last two decades, was actually worked through, and you’ll get one idea on this topic).

An effective methodology involves systematic review of patents and prior art — all publicly available information. OMS started from H.261 (the predecessor to MPEG-2, also known as H.262), because H.261 was finalized in 1989, outside the (17-year) patent window. Key tool strategies and prior art were already established in that era.

For a bit more detail on timelines see:

http://blogs.sun.com/openmediacommons/

And on the general strategy of Open Media Commons, see “Sun’s OMS Video codec project is a means to an end”
http://www.linux.com/feature/145347

Rob