Ask HN: If you develop a codec in a cleanroom is it still encumbered by patents?

Independent invention at a later date is no defense against a patent. So, you are still in trouble.

Independent invention is a defense against a copyright though.

Yes. Patents don't care if you knew about them or not.

Nope you're still liable for infringement. It does help you avoid the treble damages for "willful infringement."

Copyrights no (that's what cleanroom gets you), patents yes.