How do you adapt RTP and RTCP to different application scenarios and requirements?

2 RTCP Bandwidth

The RTCP bandwidth is the fraction of the RTP session bandwidth that is allocated for RTCP packets. RTCP packets are used to exchange control information and feedback among the RTP participants, such as sender and receiver reports, source description, and application-specific data. The RTCP bandwidth is important to balance the trade-off between the overhead and the benefits of RTCP. If the RTCP bandwidth is too low, the RTP participants may not receive enough feedback to adjust their transmission parameters, such as codec, bitrate, or packet size. If the RTCP bandwidth is too high, the RTP participants may consume too much network resources and affect the quality of the RTP stream. The RTCP bandwidth can be either fixed or adaptive, depending on the application and the network conditions.

3 RTP Header Extension

The RTP header extension is an optional feature that allows the RTP participants to add additional information to the RTP header. The RTP header extension can be used to convey application-specific or context-specific data that is not part of the standard RTP header fields, such as spatial or temporal coordinates, camera orientation, or encryption parameters. The RTP header extension can enhance the functionality and flexibility of the RTP stream, but it also increases the size and complexity of the RTP packet. Therefore, the RTP header extension should be used sparingly and only when necessary. The RTP header extension can be either defined by the IANA or negotiated by the application using protocols such as SDP.

4 RTCP Feedback

The RTCP feedback is a subset of RTCP packets that are used to provide rapid and specific feedback from the receivers to the senders of the RTP stream. The RTCP feedback can be used to signal various events or conditions that affect the quality or performance of the RTP stream, such as packet loss, delay, jitter, congestion, or bandwidth estimation. The RTCP feedback can enable the senders to adapt their transmission parameters accordingly, such as codec, bitrate, or packet size. The RTCP feedback can improve the responsiveness and efficiency of the RTP stream, but it also generates more traffic and processing load. Therefore, the RTCP feedback should be used selectively and only when needed. The RTCP feedback can be either standardized by the IETF (Internet Engineering Task Force) or customized by the application using protocols such as AVPF (Audio-Visual Profile with Feedback).

5 RTP Security

The RTP security is a set of mechanisms that protect the confidentiality, integrity, and authenticity of the RTP stream. The RTP security can prevent unauthorized access, modification, or replay of the RTP packets, as well as verify the identity and legitimacy of the RTP participants. The RTP security can be achieved by using encryption, authentication, or integrity algorithms, such as AES (Advanced Encryption Standard), HMAC (Hash-based Message Authentication Code), or SRTP (Secure Real-time Transport Protocol). The RTP security can enhance the privacy and reliability of the RTP stream, but it also requires more computation and communication resources. Therefore, the RTP security should be applied according to the sensitivity and risk level of the RTP stream. The RTP security can be either integrated with the RTP protocol or implemented as a separate layer using protocols such as DTLS (Datagram Transport Layer Security).

6 RTP Interoperability

The RTP interoperability is the ability of different RTP implementations or devices to communicate and exchange media data with each other. The RTP interoperability can be affected by various factors, such as payload type, header extension, feedback, security, or network architecture. The RTP interoperability can be enhanced by following some best practices and recommendations, such as using standardized or common payload types, avoiding unnecessary or incompatible header extensions, supporting feedback formats or mechanisms, ensuring security compatibility or negotiation, or using gateways or translators to bridge different network domains or protocols. The RTP interoperability can improve the usability and functionality of the RTP stream, but it also requires more coordination and testing among the RTP participants. Therefore, the RTP interoperability should be considered and verified during the design and deployment of the RTP stream.

7 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?