The spec already includes a "RTP matching rules" so implementors can follow, step by step, and figure out how to deal with received RTP given receive(parameters). So I suggest the spec should also include a "RTP sending rules" for implementors to figure out what exactly to do when send(parameters) is called, step by step.

After all the rationale given in #471 I do understand what the spec tries to state, but I consider it extremely difficult to be understood by newcomers by just reading the spec. So I mean guidelines such as:

• If there is no encodings create an empty one with codecPayloadType pointing to the first media codec (no DTMF, CN, etc) in the codecs list.
• If no muxId or ssrc is filled into an encoding generate random ones and fill those fields.
• For each encoding with no dependencyEncodingId field a new RTP stream is required, so uniqueness of their ssrc values is required (or fill them following that requirement).
• etc etc etc.