Linked by jrincayc on Fri 15th Jul 2011 17:14 UTC
Legal Patent term calculation is complicated in the US because there are essentially two different systems and quite a few corner cases. Even with a list of patents, it can be tricky to determine when the patents are all expired. Since I am a computer programmer (and not a lawyer), I created a program to try and automate this. This paper discusses how patent term calculation works, and some results from a combination of hand and automatic term calculation for MP3, MPEG-2 and H.264.
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RE[2]: Comment by static666
by pgeorgi on Sat 16th Jul 2011 06:22 UTC in reply to "RE: Comment by static666"
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All of those codecs can be attacked by submarine patents.

Submarine patents in their original meaning don't exist anymore: These were patents that were filed, but hold outside public view and before the clock started ticking by extending the patent text all the time.

The "clock skew" was worked around by moving to first filing date (instead of grant date), making it unattractive for the patent holder to amend patents all the time.
And I guess/hope the PTO only grants extensions if _they_ mess up, not when the patent holder amends the text to incorporates new state of the art.

The current issue is with patents that apply to some technology that weren't found on investigations, which eventually pop up.

here is no guarantee that Vorbis, Speex, Theora, VP8 are patent-free.

For Vorbis a patent search was done by AOL before some subsidiary (Nullsoft, I think) was allowed to use it. While this is still no guarantee, it's an indication that things aren't all that bad.

Theora and VP8 are _not_ patent-free, but each has the known set of patents licensed freely.

As for unknown patents, even MP3 was hit by them. Sisvel/AudioMPEG showed up late and broke the single-shop approach of

The same could happen to MPEG-LA's portfolio.
A holder of a matching patent could kill (eg.) h.264 by licensing their patent in a way that excludes parallel licensing from MPEG-LA.

This would also kill the value of that patent, but could be a strategic option, and there's nothing MPEG-LA could do about it (except by trying to invalidate the patent).

This is why they (or any other licensor) won't indemnify their licensees.

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