Stream translation and mixing

mixing	combining several RTP streams to produce a single stream
translation	converting from one encoding to another (also know as transcoding)

Each source has a unique 32 bit Synchronization Source Identifier. When several sources are mixed the new stream gets its own unique Synchronization Source Identifier and the IDs of the contributing sources are included as Contributing Source IDs, the number of which is indicated in the 4-bit CC field of the header.

Transcript

[slide96] But the cool thing now is we can do both mixing, where we take multiple RTP sessions and combine them together, but also translation, where we can now take an RTP stream encoded with one CODEC, transcode it, and send it off.