in some ways, a perpetual unrestricted license is better than an unpatented algorithm. The big excuse for not adopting webm was "uncertainty" about the patent situation. If skype has the patents and is giving free licenses, there isn't any uncertainty here, you know that microsoft has no basis to ever sue.
This is true and is one reason that free things these days are given "licenses" instead of simply being declared by their makers to be in the public domain. The public domain isn't what it used to be.
It's impossible to declare a work under the public domain in the USA. A creative work reaches the public domain only when its copyright expires, or if it's a government work.
Read up on the rationale behind the CC0 license for more information:
To some (significant) degree, but you never know that no one else has patents on a technology. That's exactly what is so messed up with software patents.
On any specific technology, you absolutely can know that no one else has patents on it. That is the responsibility of the patent office: to grant exclusive rights to an 'invention'. you cannot be held liable for infringement of anything you have a license for.
In this case though, Microsoft only has patents on part of the algorithm, so it is theoretically possible that other parts of the algorithm are covered by other patents.
It's rare, but I remember reading that USPTO has mistakenly issued conflicting patents. Legally, any publication is enough to bar others' patents, they're just not good at finding anything in the software literature, so having your own patent sort of rubs examiners' noses in it.
> On any specific technology, you absolutely can know that no one else has patents on it. That is the responsibility of the patent office: to grant exclusive rights to an 'invention'.
The problem though is that anything complex like a video or audio codec can constitute many "inventions" from the USPTO's point of view. H.264 has many patents on it, for example. Again, this is one of the big problems with the current patent system.
So in practical terms you can never use a codec with the knowledge that no one else has patents on it.
And in certain situations it's better not to know, because knowingly infringing patents can result in significantly higher monetary penalties than unknowingly infringing them.
