Google tweaks VP8 licence to calm open source critics

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Google has tweaked the licence on its VP8 video codec to head off concerns over its open source status.

The web giant has made the codec available in the latest developer build of its Chrome web browser.

It forms a key part of the WebM multimedia platform, announced by Google last month, and is based on technology inherited from the $124.6 million (85.9 million) purchase of video compression specialist On2 in February.

But Google's plans to open-source VP8 specifically under a royalty-free licence backfired when it emerged the codec's patent grant fell foul of the Open Source Initiative's (OSI) requirement for royalty-free licences to be void of any restrictions on field of use.

After a polite reminder to that effect from OSI board member Simon Phipps, Google decided instead of adjusting the terms of the licence which Phipps had said would cause a "slightly embarrassing" proliferation of licences it would simply remove the patent grant altogether and copyright the codec under a BSD licence instead.

The patent grant is now covered by a separate document altogether.

The change was announced in a blog post by Google open source manager Chris DiBona.

"Using patent language borrowed from both the Apache and GPLv3 patent clauses, in this new iteration of the patent clause we've decoupled patents from copyright, thus preserving the pure BSD nature of the copyright license," wrote DiBona.

"This means we are no longer creating a new open source copyright license, and the patent grant can exist on its own. Additionally, we have updated the patent grant language to make it clearer that the grant includes the right to modify the code and give it to others."

In response, Phipps confirmed that "the project is now fully open source, with the copyright licensed under the BSD licence".

"Many thanks to Google for addressing the concerns that I and many other members of the community expressed over the licence under which the project was initially announced. We are spared yet another open source licence, something I welcome as an OSI director."

Having now resolved the licencing issue, Google has included support for the WebM platform in version 6.0.422.0 of the developer channel version of Chrome, which is now available to download for Windows, Mac OS X and Linux users.

The Dev channel build of Chrome sees new features being opened up for testing ahead of their incorporation in official Beta releases. Similar builds featuring WebM support based on Opera and Firefox have already appeared online.

In addition to its WebM support, the latest Dev build of Chrome features fixes for a bug that caused the browser to crash when switching networks, and various Mac and Linux-specific reliability issues.

Google has also released a new Beta version of Chrome. Version 5.0.375.70 addresses various stability issues and is available now.