📝RTCP

RTCP = RTP Control Protocol.

Two types of packets: RTCP Sender/Receiver Report. Typically, one report is sent per second.

Fields:

• SSRC for each media

• CNAME — identifier to group medias together

• timestamps, packet count, jitter estimation (to help with QoS)

RTCP-FB = RTCP Feedback (for congestion control) — optional extensions

• Google REMB (Receiver Estimated Maximum Bitrate)

  • for dynamic bandwidth adaptation

• NACK

  • request to resend some packets

• NACK PLI (Picture Loss Indication)

  • request to resend a new refresh frame

• CCM FIR (Full Intra Request)

  • request to send a keyframe

These extensions are negotiated in SDP.

Backlinks

• 📝 SDP
• 📝 RTP
• 📝 Streaming