At the outset, I just want to say how happy I am that AV1 has taken off, and how seriously it is viewed by so many technology companies as a way around H.264 and (even worse) HEVC. Particularly with respect to HEVC, there are
three separate patent pools with different participants. HEVC is, in many ways, already set up to fail due to a large number of participants that participate in either none or one of the pools (see
https://streaminglearningcente... for how chaotic it is). There are some other proprietary technologies such as Perseus that are out there that claim better performance than HEVC from a PSNR/SSIM perspective, but they will likely remain fringe.
What is of more concern to me is how carefully AV1 has been constructed in terms of its coding tools to avoid patent trolling and patent submarining (e.g. Rambus at JEDEC with DDR). This is a very serious and very technically complex issue, as any company could easily assert patents on AV1 if they feel there is infringement on their claims as pertains to any of the coding tools. There are increasingly limited ways of dealing with spatiotemporal entropy in non-infringing ways that do not involve exponential increases in gates or CPU cycles.
A recent and simple example of this is the MPEG-LA claiming they license patents related to the MPEG-DASH streaming framework. MPEG-DASH is, essentially, an XML schema for a streaming manifest combined with either MPEG-4 Part 12 (the MP4 container originally specified by Apple as the MOV format), or MPEG-2 Transport Streams encapsulating H.264 video. Nobody on the DASH Industry Forum really thought that MPEG-DASH would be subject to this type of activity, yet magically MPEG-LA began waiving it agreement around about two years ago.
As a result, many in the industry have held onto the virtually universally-supported HTTP Live Streaming, which is an M3U playlist with tag extensions and MPEG-2 Transport Stream container for the codecs. Even that standard developed by Apple has never become a fully ratified within the IETF, and nobody knows if the same thing will happen there either.
Incidentally, any time Google has presented VP8 or VP9 at previous conferences and is asked about patents, they avoid answering questions and the audience usually laughs. I've seen it personally, and I think it's the industry's cynicism for the various patent holders and some of their past actions. Where it becomes critical is for silicon suppliers, whose front-loaded costs are now in the neighborhood of nine figures to launch some SoCs, and for content distributors, who invest a tremendous amount of time and money encoding all of the required profiles for streaming to new codecs. Commitment to efficient hardware acceleration by them for the codec is risky, as they could easily be legally enjoined from selling their products if they didn't get their patent licenses in order, and this would also leave content holders scrambling to fall back to already-established codecs.
I will admit I'm cynical here too. While I'd love to see a patent-free open standard, I'm not optimistic that someone will not come out of the woodwork claiming infringement on a key coding tool. I wish Google and the rest of the AV1 participants luck. They'll need it.