Google open-video codec goes experimental

Google has added an experimental branch to the VP8 code tree, encouraging developers to begin work on the next incarnation of its newly open sourced video codec.

Mountain View open sourced its $124.6 million VP8 codec less than a month ago in an effort to create a royalty free standard for web video, rolling it into a larger media format known as WebM, and WebM has already turned up in developer-build and beta browsers from Mozilla, Opera, and Google itself.

The VP8 bitstream – the format of the video itself – is fixed. As the encoder and decoder are tweaked, the project's main tree will stick to the same bitstream. But on the experimental branch, Google is already looking ahead to future versions of the codec, allowing changes to the bitstream as well. The experimental branch will house work on, say, VP9.

"To maintain codec stability while also allowing for quality and performance improvements in VP8, we have added an experimental branch to the VP8 source tree," reads a blog post from Google codec engineering manager Jim Bankoski.

"The WebM community can use this unstable branch to propose changes to VP8 that will produce the best video codec possible, but without the constraints of a frozen bitstream. At some point in the future, when the experimental branch proves significantly better than the stable branch, we will create a new version of the codec."

Google says that it already has teams of developers investigating and evaluating new techniques and that these teams "are committed to do so for the long term."

Though Mozilla and Opera have put their weight behind WebM, the two other browser vendors have not. Steve Jobs has indicated that Apple will stick with H.264, a royalty encumbered codec licensed by the MPEG LA. And though Microsoft says it will allows netizens to use WebM if they load it on their own systems, IE9 will only includes H.264 as well. Both Apple and Microsoft are part of the MPEG LA patent pool that backs H.264.

The MPEG LA has said its putting together a patent pool for VP8, which would challenge Google's effort to make the codec royalty free. In open sourcing the codec, Mountain View has also granted rights to the various Google-owned patents backing the technology. Google acquired VP8 as part of its $124.6 million purchase of video compression outfit On2 Technologies.

On YouTube, Google is already encoding larger videos with VP8, and various partners are working to provide hardware acceleration for the format. Bankoski says that these partners are committed to providing hardware based sometime next year. So the current bitstream will stay in place for at least a few years.

"Devices that use hardware acceleration for video are a very small percentage of overall web traffic today, but they are a rapidly growing segment of the market and our project must be mindful of these vendors' needs," he writes. "Given the longer lead times for changes in chipsets, hardware companies implementing the codec today need to be confident that it will be stable and supported as VP8 content proliferates." ®