SDP signaling and negotiation for media plane
Media plane adaptation is done at the SBC for network carried media, Media plane adaptation/support should be done for all network hosted media services which face peer-to-peer media clients SBC is utilized to enhance compatibility by modifying SDP contents as necessary and engaging appropriate media servers or transcoding resources. The high-level architecture elements of WebRTC media streams can be divided into two areas:
Adaptation of WebRTC Media Plane to IMS Media Plane
General – oEncryption, RTP Multiplexing, Support for ICE Audio -oInterworking of differing WebRTC and codec sets Video -o Use of VP8 o Support for H.264 Data -oSupport of MSRP ( RCS standard for messaging over DataChannel API)
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.
|Audio||G.711, Opus||G.711, AMR, AMR-WB (G.722.2)|
|Audio – Extended||G.729a[b], G.726|
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