WebRTC Media Streams

SDP signaling and negotiation for media plane

Read more on SDP and its attributes : https://telecom.altanai.com/2014/01/03/sip-in-depth/(opens in a new tab)

Media plane adaptation is done at the SBC for network carried media, it should be done for all network hosted media services which face peer-to-peer media.

The high-level architecture elements of WebRTC media streams can be divided into two areas:

Adaptation of WebRTC Media Plane to IMS Media Plane

Encryption, RTP Multiplexing, Support for ICE —

Audio – Interworking of differing WebRTC and codec sets —

Video – Use of VP8 , Support for H.264 —

Data – Support of MSRP ( RCS standard for messaging over DataChannel API)

—Peer-to-Peer Media

Direct connection to media servers and media gateways .—

Use common codec set wherever possible to eliminate transcoding —Use regionalized transcoding where common codec not available Note: Real-time video transcoding is expensive and performance impacting

On-going standards/device/network work needs to be done to expand common codec set. WebRTC codec standards have not been finalized yet. WebRTC target is to support royalty free codecs within its standards. —

MediaWebRTClegacy
AudioG.711, OpusG.711, AMR, AMR-WB (G.722.2)
Audio – ExtendedG.729a[b], G.726
VideoVP8H.264/AVC

Supporting common codecs between VoLTE devices and WebRTC endpoints requires one or more of the following: 1.Support of WebRTC codecs on 3GPP/GSMA 2.Support of 3GPP/GSMA codecs on WebRTC 3.WebRTC browser support of codecs native to the device

References :

https://tools.ietf.org/id/draft-ietf-rtcweb-sdp-08.html#rfc.section.5.2.8