If there's any software that has a chance of convincing me of patent worthiness, it's probably codecs. Or at least the co(d) part. I'm muddled on decoding because it seems like just figuring out how to read something should be treated differently.
Is the term 20 years now? That's too long for any kind of software, even codecs. I think an important principle that should influence the design of patent law is the rough likelihood of the invention being made by others, or qualitatively matched or exceeded by others, in various spans of time. (Of course you have to model this assuming certain patent laws in place, as well as no patent system at all, to really do it right.)
I despise patent predators, née trolls. But MPEG-LA isn't a good example for me to work with because I think they're actual companies that do stuff – make movies, Blu-ray players, TVs, etc. Some of them invented DVD and Blu-ray probably, and evidently they invented MPEG-2, which I remember was viewed as pretty slick and technically awesome when it came out (as were DVDs – I remember VCRs and boy did they suck).
But 20 years? Yeah, no, this stuff should be 10 at most. I mean, would it hurt us to have 10 year terms on codecs? Would we get lesser quality codecs? I doubt it. HEVC is pretty amazing though, and it's clearly better than VP9, so it looks like the proprietary stuff beats open source in this field (tiny sample, yes, but there are many more examples available). Daala seemed to be going nowhere. Mozilla didn't seem to be able to finish it. Now some companies have teamed up for AV1, FOSS. I guess we'll see how good it is compared to HEVC.