When a stream of packets is received by the media engine, it is not guaranteed that everything sent gets received.
In case not all packets are received, and no FEC is employed (or is usable), packet loss concealment comes into play.
Packet loss concealment isn’t standardized anywhere and is left for the implementer of the media engine and codec.
WebRTC Glossary is a collaborative space where users can learn more about WebRTC related terms. Anyone can also modify or add new terms to this glossary, but it requires registration to the site first.