RTCSessionDescriptionInit

RTCSessionDescriptionInit is a WebRTC initialization dictionary used to create or configure a session description. A session description represents the parameters exchanged during the negotiation of media streams between peers, typically encapsulated as SDP data.

The RTCSessionDescriptionInit dictionary contains two main properties: type and sdp. The type property is a string that indicates the SDP type, commonly values such as "offer" or "answer" as defined by RTCSdpType. The sdp property is a string containing the Session Description Protocol data that describes the media capabilities, codecs, timing, and related session information.

This dictionary is used as an input when constructing an RTCSessionDescription, for example via new RTCSessionDescription(init), or when providing initialization data to methods that accept an initialization object (such as setLocalDescription or setRemoteDescription in certain APIs). In practice, you create an object with type and sdp, then pass it to the constructor or relevant API to produce or update the session description used during negotiation.

Compatibility and details: RTCSessionDescriptionInit is part of the WebRTC specification and helps standardize how session descriptions are created and passed between peers. The sdp field must contain valid SDP text corresponding to the specified type; otherwise, an error may occur during creation or negotiation.

See also: RTCSessionDescription, RTCSdpType, and SDP in WebRTC negotiation.