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Direct link to 1.0.0 spec (PDF): https://github.com/AOMediaCodec/av1-spec/releases/download/v1.0.0/av1-spec-v1.0.0.pdf https://github.com/AOMediaCodec/av1-spec/

Direct link to 1.0.0 spec (PDF): https://github.com/AOMediaCodec/av1-spec/releases/download/v1.0.0/av1-spec-v1.0.0.pdf https://github.com/AOMediaCodec/av1-spec/releases/download/v... Unofficial working copy (HTML): https://aomediacodec.github.io/av1-spec/ https://aomediacodec.github.io/av1-spec/ Source (of spec): https://github.com/AOMediaCodec/av1-spec/tree/v1.0.0 https://github.com/AOMediaCodec/av1-spec/tree/v1.0.0 AV1 is a video codec developed by a consortium of companies, broadly descending from Google's VP9 while incorporating significant enhancements from Cisco and Xiph.Org. The participant companies are numerous and include big chipmakers and content delivery networks, banding together to perpetuate a royalty-free video codec that mounts a competition against MPEG's efforts, whose rules don't exclude techniques that are patented. This is news because previous for previous codecs in this bloodline, like VP8 and VP9, the bitstream has never been frozen [1][2]. This wishiwashiness didn't preclude hardware implementations, and certainly not software implementations, but was very much a departure of the orthodox, old-hat practice in the standard-speccing space. With AV1, they're trying an approach that competes more directly with the MPEG specs, by having a bitstream that's not a moving target and is more formal than just a document embarrassingly marked as draft [2]. [1] http://blog.webmproject.org/2010/06/future-of-vp8-bitstream.html http://blog.webmproject.org/2010/06/future-of-vp8-bitstream.... [2] https://www.webmproject.org/vp9/#draft-vp9-bitstream-and-decoding-process-specification https://www.webmproject.org/vp9/#draft-vp9-bitstream-and-dec...

quikee 8y ago
No. VP8 and VP9 bitstreams are frozen and stayed frozen when they decided to freeze it (they made that sure with automatic tests in libvpx that calculated the bitstream checksum) otherwise old VP8/VP9 files would stop playing. The difference is only with the approach as with VP8 and VP9 the "reference" decoder is the specification, which is not what many people like for various reasons (for example there were some errors in the implementation, which needed to be implemented by everyone because of that). The first link you posted about VP8 just writes that they'll create an experimental branch (back in 2010) where incompatible bitstream changes can go in. Guess what eventually happened with those changes? VP9 The second link is the link to the unfinished VP9 specification, however with VP9 they still had that "reference" decoder code is the specification approach. As VP9 started to gain traction, the demand for the specification became greater, so they post-hoc started writing one but as you can see, they never finished it. Still this doesn't mean the bitstream isn't frozen.

quikee 8y ago

No. VP8 and VP9 bitstreams are frozen and stayed frozen when they decided to freeze it (they made that sure with automatic tests in libvpx that calculated the bitstream checksum) otherwise old VP8/VP9 files would stop playing. The difference is only with the approach as with VP8 and VP9 the "reference" decoder is the specification, which is not what many people like for various reasons (for example there were some errors in the implementation, which needed to be implemented by everyone because of that). The first link you posted about VP8 just writes that they'll create an experimental branch (back in 2010) where incompatible bitstream changes can go in. Guess what eventually happened with those changes? VP9 The second link is the link to the unfinished VP9 specification, however with VP9 they still had that "reference" decoder code is the specification approach. As VP9 started to gain traction, the demand for the specification became greater, so they post-hoc started writing one but as you can see, they never finished it. Still this doesn't mean the bitstream isn't frozen.