How does this work, exactly?

Our organization is in Germany, which pretty clearly shouldn't see any of the h264 patents as valid. However, other countries might still drag our organization in front of their courts. Other countries might also hold individual contributors instead of the organization accountable. Then there are extradition agreements.
If it was just me, I would take the risk and break the patents. But we have at least one contributor who is worried about knowingly breaking laws in other countries, which have extradition agreement.

Alternatively, you can get a license from the relevant consortium; Not only does that not guarantee that you aren't still infringing on patents, but it is also an 80-page document full of stuff that doesn't make any sense. I cannot sign something like that in good faith. And realistically nobody can sign that in good faith.
Not to mention, you need multiple licenses, because usually you use a proprietary audio codec like AAC together with h264. By signing a contract with then, you also imply that their patents are legitimate, which I would also never want to do if I can help it.

So in our case, we just accept that we won't support proprietary codecs. It's a pretty big annoyance in our case, but there is just no way to do it right.