If you encode a video using one of these (open-source) unlicensed encoders, you’re practicing patents without a license, and you can be sued. But hey, maybe you’re just a scofflaw. After all, it’s not like you’re making trouble for anyone else, right? Wrong. If you send a video to a friend who uses a licensed decoder, and they watch it, you’ve caused them to violate their own software license, so they can be sued too.
Замечательная статья про особенности лицензирования H.264