RTCSessionDescription

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since January 2020.

The RTCSessionDescription interface describes one end of a connection—or potential connection—and how it's configured. Each RTCSessionDescription consists of a description type indicating which part of the offer/answer negotiation process it describes and of the SDP descriptor of the session.

The process of negotiating a connection between two peers involves exchanging RTCSessionDescription objects back and forth, with each description suggesting one combination of connection configuration options that the sender of the description supports. Once the two peers agree upon a configuration for the connection, negotiation is complete.

Constructor

RTCSessionDescription()

Creates a new RTCSessionDescription by specifying the type and sdp. All methods that accept RTCSessionDescription objects also accept objects with the same properties, so you can use a plain object instead of creating an RTCSessionDescription instance.

Instance properties

The RTCSessionDescription interface doesn't inherit any properties.

RTCSessionDescription.type Read only

An enum describing the session description's type.

RTCSessionDescription.sdp Read only

A string containing the SDP describing the session.

Instance methods

The RTCSessionDescription doesn't inherit any methods.

RTCSessionDescription.toJSON()

Returns a JSON description of the object. The values of both properties, type and sdp, are contained in the generated JSON.

Example

js
signalingChannel.onmessage = (evt) => {
  if (!pc) start(false);

  const message = JSON.parse(evt.data);
  if (message.type && message.sdp) {
    pc.setRemoteDescription(
      new RTCSessionDescription(message),
      () => {
        // if we received an offer, we need to answer
        if (pc.remoteDescription.type === "offer") {
          pc.createAnswer(localDescCreated, logError);
        }
      },
      logError,
    );
  } else {
    pc.addIceCandidate(
      new RTCIceCandidate(message.candidate),
      () => {},
      logError,
    );
  }
};

Specifications

Specification
WebRTC: Real-Time Communication in Browsers
# rtcsessiondescription-class

Browser compatibility

BCD tables only load in the browser

See also