RtpPacketFec is a forward error correction packet. It is used to provide error correction for data packets that may become lost. It has a fixed payload type PayloadType.FEC The normal Rtp Timestamp has been repurposed in order to save bytes. It is split into... FecIndex - the index of this packet within the fec packet[]. The size of the fec packet[] is either determined by the constant fec ratio, or the percent coverage across a chunk. DataRangeMin - the starting data packet sequence number for which this packet provides coverage. PacketsInFrame - how many packets are in a chunk. Used in the event that no data packets are received, but enough fec packets arrive to recover the data. 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |V=2|P|X| CC |M| PT.FEC | sequence number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | DataRangeMin | PacketsInFrame | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | synchronization source (SSRC) identifier | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | FecIndex | +=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+
