Here is some background information on Forgent's patent
no. 4,698,672, October 6, 1987 (filed October 27, 1986),
"Coding system for reducing redundancy". Forgent claims that
JPEG codecs infringe on their patent, and they have recently
begun enforcing their claim.
The JPEG committee is
coordinating the effort to collect prior art; it's not my intention to compete with
that effort, and I will forward anything submitted here to them. Prior art, to
be most useful, should consist of published reports appearing earlier than
October 27, 1985.
The patent: Search for "4,698,672" at
- News Reports and discussions:
Forgent timeline 8 July 2002 (PDF):
Forgent press release 11 July 2002:
- Slashdot discussion 18 July 2002:
- Infoworld article 19 July 2002:
- Statement by JPEG Committee 21 July 2002, announcing plans to set up a
web site to collect prior art:
- ZDNet|UK| article 22 July 2002: "JPEG committee refutes patent claim"
- Slashdot discussion 21 July 2002:
c|net News.com, 22 July 2002: "Finding patent truth in JPEG claim"
The Register 23 July 2002: ISO to withdraw JPEG standard
- Slashdot discussion 23 July 2002:
- ZDNet article 23 July 2002:
- The New York Times, "Patent Claim Strikes an Electronics Nerve",
29 July 2002:
- Algovision: JPEG und JPEG2000 - zwischen Patentstreit und
- Heisse Online: Das JPEG-Patent -- ein alter Hut?, 28 August 2002:
http://www.algovision-luratech.com/company/news/newsletter/2002_08_23_en.jsp, 27 August 2002: "JPEG Patent Quarrel: First
Comprehensive Analysis by the Experts."
Does JPEG Infringe on the Patent US 4698672 held by Forgent Networks?
The Answer is NO.
- ABC News
August 29, 2002: "Picture This --
Firm Stakes Claim to Web Image Technology; Who Will Pay for its Use?
- Acorn Press On Line
October 2002: End of the road for JPEGs? --
how Forgent threw a spanner into open standards
- The League for Programming Freedom is also collecting links about this
- There is an extensive collection of links on this issue at
This matter is of interest to MNG Development because MNG uses the JNG subformat
which is simply baseline JPEG wrapped in PNG-style chunks.
It would be very useful for someone to scrutinize the patent to determine
exactly which, if any, of its claims are infringed by JPEG codecs. There
has already been some preliminary analyses by compression experts.
Tom Lane of IJG was quoted (in the July 19 Infoworld article referenced
above) to say that it does not. Mark Nelson has also said in the
comp.compression newsgroup (search
Google Groups for "jpeg patent nelson")
that there is probably no overlap.
If you have any technical information on this patent that you are willing to
share, send it to
possible inclusion on this page.