Wednesday, May 19, 2010

How free is Google's VP8 (WebM)?

Thank you Google for using your wealth to purchase On2 corporation and release VP8 to the world. However, there appears to be one glaring flaw in the patent license you offer which makes it incompatible with free software licensing: it appears to only cover the VP8 bitstream itself, not improvements to it made by the community.

When On2 previously released VP3.2 to the Xiph foundation and the world, the patent license explicitly included derivatives (improvements) to VP3.2 including Ogg Theora. This was a critical step in transitioning the proprietary VP3.2 codec to the open codec Theora is today.

On2's "VP" codecs included little extensibility, why should they as On2's revenue stream depended on releasing (and offering a new license for) a new improved codec version every year or two. You cannot use their VP5 codec to decode VP6, you need to get a VP6 codec for that. In contrast, Vorbis is ten years old now and is still being improved on.

The large body of work undertaken primarily by Tim and Ralph at Xiph before Theora 1.0 could be released was extending the bitstream in a losslessly upgradable manner from VP3.2 to include the fields necessary to continually improve Theora over the next decade and beyond. You can see this by playing a VP3.2 video next to a Theora 1.1 video, and even more so in the Theora 1.2-beta9 comparisons, and they've barely scratched the surface still.

For comparison, On2 corporation's patent license for VP3.2 can be found in the Theora license file vs Google's VP8 bitstream license. As I'm not a lawyer, I would love to hear SFLC's evaluation of this in their next Oggcast.

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