Implementations only update getParameters().codecs when negotiation has finished about webrtc-pc

[alvestrand]

Seems like we want this getter to reflect the content of the currently negotiated SDP description, and this is independent of the SendCodecs and ReceiveCodecs (it's a shorthand for an SDP parser).

[jan-ivar]

Seems like we want this getter to reflect the content of the currently negotiated SDP description,

Yes, that seems a useful way to look at it.

and this is independent of the SendCodecs and ReceiveCodecs (it's a shorthand for an SDP parser).

Internal slots are cheap, as long as we're not confusing things we can do it a couple of ways.

But for consistency with 1.0 (and TR) we may wish to keep [[SendCodecs]] and [[ReceiveCodecs]] the same, doing their old job of reflecting currentDescription (at least as implemented when it comes to [[ReceiveCodecs]]). E.g. start out empty (when currentDescription is null).

In #2956 (comment) I proposed some new internal slots.

[alvestrand]

Having slept on it, it seems that we've been using SendCodecs and ReceiveCodecs for two different things:

• Representing the capabilities of the transceiver (used to be the capabilities of the platform)
• Representing the current set of negotiated codecs
  It seems logical that this needs to be two different internal slots. The "current set of negotiated codecs" doesn't need the Enabled bit - it can be just a simple representation of what's in the currently valid SDP.

Suggested new names:
[[NegotiatedCodecs]] - occurs both in sender and receiver (has PT, does not have Enabled)
[[AvailableCodecs]] - occurs both in sender and receiver (has Enabled, does not have PT)