The courts determine the applicability of single patents, or a single parties patents (e.g. in cases of misconduct). There is no legal process that can prove something non-infringing, unless you expect something to go to court millions of times.
But this doesn't mean that something can't be designed in a way which avoids all known, and much unknown risk, and licensed in a way which makes frivolous attack less likely.
The obsessives here somes forget that when we talk about comparing things what matters is the relative merits. The commercial codes are absolutely and uncertainly encumbered. And the commercial codec providers have generally had a poor track record of creating codecs unencumbered by third party rights (mostly because they don't make an effort to: they erroneously assume the regular royalties will satisfy all comers). Opus doesn't have these issues and even compared to most software an effort was made to avoid infringement, but nothing can escape the impossibility of absolute certainty under the current patent system.
But this doesn't mean that something can't be designed in a way which avoids all known, and much unknown risk, and licensed in a way which makes frivolous attack less likely.
The obsessives here somes forget that when we talk about comparing things what matters is the relative merits. The commercial codes are absolutely and uncertainly encumbered. And the commercial codec providers have generally had a poor track record of creating codecs unencumbered by third party rights (mostly because they don't make an effort to: they erroneously assume the regular royalties will satisfy all comers). Opus doesn't have these issues and even compared to most software an effort was made to avoid infringement, but nothing can escape the impossibility of absolute certainty under the current patent system.