Additional IP Rights Grant (Patents)

"These implementations" means the copyrightable works that implement 
the WebM codecs distributed by Google as part of the WebM Project.

Google hereby grants to you a perpetual, worldwide, non-exclusive, 
no-charge, royalty-free, irrevocable (except as stated in this section) 
patent license to make, have made, use, offer to sell, sell, import, 
transfer, and otherwise run, modify and propagate the contents of these 
implementations of WebM, where such license applies only to those 
patent claims, both currently owned by Google and acquired in the 
future, licensable by Google that are necessarily infringed by these 
implementations of WebM. This grant does not include claims that would 
be infringed only as a consequence of further modification of these 
implementations. If you or your agent or exclusive licensee institute 
or order or agree to the institution of patent litigation or any other 
patent enforcement activity against any entity (including a cross-claim 
or counterclaim in a lawsuit) alleging that any of these 
implementations of WebM or any code incorporated within any of these 
implementations of WebM constitutes direct or contributory patent 
infringement, or inducement of patent infringement, then any patent 
rights granted to you under this License for these implementations of 
WebM shall terminate as of the date such litigation is filed.
