Module answer 

Offer/answer (RFC 3264).

A pure function. The rules here are full of cases that are awkward to reach through a live call — a stream with no common codec, an offer that reorders media, a sendonly that must become recvonly — and they are all one function call away.

The rule that shapes everything: the answer has the same number of m= lines as the offer, in the same order. A stream that cannot be accepted is answered with port 0, not omitted. Omitting it shifts every stream after it, so the two ends disagree about which stream is which — and that is a call where video arrives on the audio port.

Structs

Capabilities

What this side can do.

Functions

answer

Build an answer to an offer.

fingerprint_of

The fingerprint that applies to a stream: the media-level one, or the session-level fallback.

negotiate_direction

The direction an answer may carry, given what was offered and what this side wants.

setup_of

The setup role that applies to a stream: media level first, then the session default.