PDF and some possible embedded data formats are patent encumbered.
There are IPR disclosures available.
Read Adobe's RFC 3667 disclosure. They grant a royalty-free
anyone who wants to write software to manipulate PDFs, as
long as they
are compliant to the specification.
Sounds sufficient to my (IPR trained) eyes.
Your IPR-trained opinion doesn't mean much to me when Adobe
is threatening to sue people (even if it is MS).
In point of fact the above license is exactly the form of license that Sun
attempted to sue Microsoft over.
Regardless of what you believe the merits of that suit to be, the ability for
one party to unilaterally determine the future of a specification and exclude
other changes under threat of law is certainly not what I consider to be an
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