RTP packet

An RTP packet is encapsulated in a UDP packet. Usually a UDP packet carries only one RTP packet.

The fields are described as follows:

• V—2 bits, version number.

• P—1 bit, padding flag.

• X—1 bit, packet header extension flag.

• CC—4 bits, contributor count.

• M—1 bit, special event flag.

• PT—7 bits, payload type flag.

• Sequence Number—16 bits, data packet sequence number.

• Time Stamp—32 bits, time stamp.

• SSRC—32 bits, synchronization source identifier.

• CSRC identifiers—32 bits, list of contributing source identifiers. The number of contributing source identifiers depends on the value of the CC field. The CSRC identifiers field can contain up to 15 contributing source identifiers.

• Payload—Packet payload.