H.264 patents are not expiring yet, if anyone was wondering. 2027 seems to be when that happens. On the other hand, I believe H.263 patents already expired, and MPEG-4 ASP (DivX etc.) is expiring this year.
We have lots of tools that didn't make it into H.264 standard due to complexity are also expiring.
For example: FLAC
With much fanfare, iOS11 (2017) was the first time iOS supported playing FLAC files and that was (and still is) not the Apple-branded “Music” app but only in the “Files” app.
One could argue about patent system and its usage, but most companies ( ignoring Tech and Internet companies ) tend to avoid them. Especially when there are alternative.
And consumer tends to just use whatever they want. I remember I picked Wavepack over FLAC in that era. But I cant record the reason any more it was just too long ago.
What is that difference? It's not like you can proove that anything is not covered by any patent without being sued by every patent holder and winning.
When you have a codec that have all patent expired after 20 years. That is guaranteed patent free, because you can no longer extract patent from it. Claiming you dont have any patent just means you think it is not covered by any patents until proven.
While I know through experience that you have a point about some companies avoiding anything that might be patent encumbered, and that the statement “[FLAC is not] covered by any known patent.“ would be a red flag to them, the argument falls down when we talk about how much code has been used over the years by companies who stepped all over the intellectual property rights of the authors.
Even if we look at Mp3s which are definitively patent-encumbered and commercially-licensed, here have been thousands of devices that played Mp3s before they a license (if they ever got one at all).
Interestingly enough, there's some non-standard-essential patents still floating around out there. For example, Mediatek patented converting Sorenson Spark bitstreams for decoding with standards-compliant H.263 hardware decoders[1], and that patent is still live until later in this decade.
[0] I wrote a Sorenson-flavored H.263 decoder in Rust for integration into Ruffle.
[1] The invention is literally just truncation-with-saturation wrapped in a bunch of patent language. If you have the money to front a legal fight against them, feel free to get the patent invalidated. But I don't think it matters.
This is the case with MPEG-2 formats used in DVD Video, and the reason that the VLC Media Player exists as a French student research project distributed as source code instead of a normal library.
Related: https://www.gnu.org/philosophy/software-patents.en.html
In other parts of the world (like large parts of Europe, for example) software patents are practically unenforceable and you can probably distribute your code as you see fit. Code is still copyrightable, so you can't just redistribute someone else's library, but your own code does not violate their copyright.
Some greedy American companies will probably still sue you if you do, hoping to enforce their patents regardless or at least scare you into paying them, but at legally you _should_ be in the clear.
When it comes to dedicated hardware for an algorithm, though, like hardware accelerated video codecs, you'll likely run into patent trouble in most of the world if you choose to build your own hardware for a patented system.