Re: Issue 149: "Automatic" use of scalable video coding?

For the behavior on the receiver side, here is some proposed text for Section 9.8.1:

encodingId of type DOMString
An identifier for the encoding object. This identifier should be unique within the scope of the localized sequence of RTCRtpEncodingParameters for any given RTCRtpParameters object. For a codec (such as VP8) where a compliant decoder is required to be able to decode anything that an encoder can send, it is not necessary to specify the expected scalable video coding configuration on the receiver via use of encodingId (or dependencyEncodingIds). Where specified for a receiver, the expected layering is ignored.