Guessing you wanted "standards organisation" and technically MPEG is a Working Group of a Subcommittee of the Joint Technical Committee between ISO and IEC.
Patents are sad because they create an incentive to argue for a technically inferior choice that you "own" over a superior choice that you don't own.
CA/B Forum (which isn't an SDO but bear with me) ran into trouble when setting up the Ten Blessed Methods (our name, not theirs) for validating control over an FQDN because it turns out some ways to implement these methods were patented by members. Although CA/B isn't an SDO, the effect of it making rules about how things are done is to set a standard, since all significant vendors in this space are members of CA/B, and all major trust stores require you to obey CA/B rules even if you're not a member.
The patents didn't cover any of the good ways to implement the Ten Blessed Methods. Literally in every case the patent described the most unsatisfactory half-arsed way to achieve something you could imagine, the existence of these patents was causing vendors to prefer to do something bad (which they'd patented) rather than something good (which they had not). But there was a reluctance to just say "OK, we patented all this stinking garbage, but forget about that" and get on with it, this stalled things for many months. After all patents aren't free, who wants to admit they bought something worthless? Ugh.
As it's constructed and the different patent pools involved, I'm not sure that a patent holder could benefit more than others by having MPEG use their patent.
That being said, patents are still annoying when you bump in to them. MPEG is remarkable in terms of the amount of interop though, you can watch video on your phone, laptop or your 4k TV all made by different vendors with different parts.