Unfortunately, from a legal point of view, AOMedia hasn't done anything against Dolby. It's simply created a video compression codec. It doesn't use the codec, it just publishes documentation on how to use it.
From a patent law point of view, it is illegal to create something that violates a patent, not just to use it. Patent law kicks in when you create, offer for sale, sell, import, or otherwise distribute a patented invention.
IMO, one of the biggest flaws in patent law is that it covers the use of inventions in all cases except for patent exhaustion (sale of an already-licensed product). With the exception of pure process patents, IMO, that should not be a violation, as a user has no realistic way of knowing that something they bought violates someone else's patent, and should not even need to worry about such nonsense.
This "feature" of patent law exists solely to give the patent holder more leverage to screw the company accused of violating the patent by holding their innocently infringing customers liable, causing irreparable reputational damage to both companies, irreparable harm to countless others, etc., and it should have been eliminated decades ago.
That said, having seen this behavior by Dolby, I hereby vow to never knowingly buy any product that they manufacture, nor support their products or technology, nor use it except in situations where the content creator or distributor leaves me no alternative. They've gone from being a legitimate technology company to a glorified patent troll. Instead of innovating and making the world better to enrich themselves, they are suing anybody and everybody and making the world worse to enrich themselves.
Moreover, absent gross incompetence by Dolby's legal counsel, it seems clear that Dolby flagrantly and willfully violated the doctrine of Laches to allow damages to accumulate for eight full years from the final release (and ten years from the first specification release), thus allowing AV1 to become the dominant codec so that they could then predatorily use their patents to squeeze money out of the industry. Their behavior is nothing short of unconscionable, and whether due to incompetence or malice, their legal counsel should be formally sanctioned for it.
Finally, if Dolby wins, it is paramount that the entire technology industry agree to never license *any* future Dolby technologies going forwards, because doing so will only encourage them to use the patent system to prevent free and open standards. The only way to prevent patent abuse is to stop feeding the companies that abuse patents.
It is my fundamental believe that data formats should not be allowed to be protected by copyright or patents under any circumstances, because doing so fundamentally violates the rights of the owners and creators of that content. It makes it so that users can potentially lose access to data that they created. And this is wholly unacceptable for the same reason that renting software is unacceptable.
In short, Dolby and its lawyers can go f**k themselves with a shovel.