Initial Author of this Specification was Ian Hickson, Google Inc., with the following copyright statement:
 © Copyright 2004-2011 Apple Computer, Inc., Mozilla Foundation, and Opera Software ASA. You are granted a license to use, reproduce and create derivative works of this document.
All subsequent changes since 26 July 2011 done by the W3C WebRTC Working Group are under the following Copyright:
© 2011-2012 W3C® (MIT, ERCIM, Keio, Beihang), All Rights Reserved. Document use  rules apply.
For the entire publication on the W3C site the liability and trademark rules apply.
This document defines a set of ECMAScript APIs in WebIDL to allow media to be sent to and received from another browser or device implementing the appropriate set of real-time protocols. This specification is being developed in conjunction with a protocol specification developed by the IETF RTCWEB group and an API specification to get access to local media devices developed by the Media Capture Task Force.
This section describes the status of this document at the time of its publication. Other documents may supersede this document. A list of current W3C publications and the latest revision of this technical report can be found in the W3C technical reports index at http://www.w3.org/TR/.
This document is neither complete nor stable, and as such is not yet suitable for commercial implementation. However, early experimentation is encouraged. The API is based on preliminary work done in the WHATWG. The Web Real-Time Communications Working Group expects this specification to evolve significantly based on:
This document was published by the Web Real-Time Communications Working Group as an Editor's Draft. If you wish to make comments regarding this document, please send them to public-webrtc@w3.org (subscribe, archives). All comments are welcome.
Publication as an Editor's Draft does not imply endorsement by the W3C Membership. This is a draft document and may be updated, replaced or obsoleted by other documents at any time. It is inappropriate to cite this document as other than work in progress.
This document was produced by a group operating under the 5 February 2004 W3C Patent Policy. W3C maintains a public list of any patent disclosures made in connection with the deliverables of the group; that page also includes instructions for disclosing a patent. An individual who has actual knowledge of a patent which the individual believes contains Essential Claim(s) must disclose the information in accordance with section 6 of the W3C Patent Policy.
This section is non-normative.
There are a number of facets to video-conferencing in HTML covered by this specification:
This document defines the APIs used for these features. This specification is being developed in conjunction with a protocol specification developed by the IETF RTCWEB group and an API specification to get access to local media devices [GETUSERMEDIA]developed by the Media Capture Task Force. An overview of the system can be found in [RTCWEB-OVERVIEW] and [RTCWEB-SECURITY].
As well as sections marked as non-normative, all authoring guidelines, diagrams, examples, and notes in this specification are non-normative. Everything else in this specification is normative.
The key words MUST, MUST NOT, REQUIRED, SHOULD, SHOULD NOT, RECOMMENDED, MAY, and OPTIONAL in this specification are to be interpreted as described in [RFC2119].
This specification defines conformance criteria that apply to a single product: the user agent that implements the interfaces that it contains.
Implementations that use ECMAScript to implement the APIs defined in this specification must implement them in a manner consistent with the ECMAScript Bindings defined in the Web IDL specification [WEBIDL], as this specification uses that specification and terminology.
The EventHandler
    interface represents a callback used for event handlers as defined in
    [HTML5].
The concepts queue a task and fires a simple event are defined in [HTML5].
The terms event, event handlers and event handler event types are defined in [HTML5].
The terms MediaStream, MediaStreamTrack, Constraints, and Consumer are defined in [GETUSERMEDIA].
An  allows two users to
      communicate directly, browser to browser. Communications are coordinated
      via a signaling channel which is provided by unspecified means, but
      generally by a script in the page via the server, e.g. using
      RTCPeerConnectionXMLHttpRequest.
dictionary RTCConfiguration {
    sequence<RTCIceServer> iceServers;
    RTCIceTransports       iceTransports = "all";
    RTCIdentityOption      requestIdentity = "ifconfigured";
};RTCConfiguration MembersiceServers of type sequence<RTCIceServer>An array containing URIs of servers available to be used by ICE, such as STUN and TURN server.
iceTransports of type RTCIceTransports, defaulting to "all"Indicates which candidates the ICE engine is allowed to use.
requestIdentity of type RTCIdentityOption, defaulting to "ifconfigured"See the requestIdentity member of
            the  dictionary.RTCOfferAnswerOptions
dictionary RTCIceServer {
    (DOMString or sequence<DOMString>) urls;
    DOMString                          username;
    DOMString                          credential;
};RTCIceServer Memberscredential of type DOMStringIf this  object represents a
            TURN server, then this attribute specifies the credential to use
            with that TURN server.RTCIceServer
urls of type (DOMString or sequence<DOMString>)STUN or TURN URI(s) as defined in [RFC7064] and [RFC7065] or other URI types.
username of type DOMStringIf this  object represents a
            TURN server, then this attribute specifies the username to use with
            that TURN server.RTCIceServer
In network topologies with multiple layers of NATs, it is desirable to have a STUN server between every layer of NATs in addition to the TURN servers to minimize the peer to peer network latency.
An example array of RTCIceServer objects is:
[ { "urls": "stun:stun1.example.net" }, { "urls":
        "turn:turn.example.org", "username": "user", "credential": "myPassword"
        } ]
        
enum RTCIceTransports {
    "none",
    "relay",
    "all"
};| Enumeration description | |
|---|---|
none | The ICE engine MUST not send or receive any packets at this point. | 
relay | The ICE engine MUST only use media relay candidates such as candidates passing through a TURN server. This can be used to reduce leakage of IP addresses in certain use cases. | 
all | The ICE engine may use any type of candidates when this value is specified. | 
These dictionaries describe the options that can be used to control the offer/answer creation process.
dictionary RTCOfferAnswerOptions {
    RTCIdentityOption requestIdentity = "ifconfigured";
};RTCOfferAnswerOptions MembersrequestIdentity of type RTCIdentityOption, defaulting to "ifconfigured"The requestIdentity
            option indicates whether an identity should be requested. The option
            may be used with either of the createOffer() or
            createAnswer() calls, but also with the 
             constructor. Note that as long as
            DTLS-SRTP is in used, fingerprints will be sent regardless of the
            value of this option.RTCPeerConnection
dictionary RTCOfferOptions : RTCOfferAnswerOptions {
    long    offerToReceiveVideo;
    long    offerToReceiveAudio;
    boolean voiceActivityDetection = true;
    boolean iceRestart = false;
};RTCOfferOptions MembersiceRestart of type boolean, defaulting to falseWhen the value of this dictionary member is true, the
            generated description will have ICE credentials that are different
            from the current credentials (as visible in the
            localDescription attribute's SDP). Applying the
            generated description will restart ICE.
When the value of this dictionary member is false, and the
            localDescription attribute has valid ICE
            credentials, the generated description will have the same ICE
            credentials as the current value from the
            localDescription attribute.
offerToReceiveAudio of type longIn some cases, an RTCPeerConnection may wish to
            receive audio but not send any audio. The
            RTCPeerConnection needs to know if it should signal to
            the remote side whether it wishes to receive audio. This option
            allows an application to indicate its preferences for the number of
            audio streams to receive when creating an offer.
offerToReceiveVideo of type longIn some cases, an RTCPeerConnection may wish to
            receive video but not send any video. The
            RTCPeerConnection needs to know if it should signal to
            the remote side whether it wishes to receive video or not. This
            option allows an application to indicate its preferences for the
            number of video streams to receive when creating an offer.
voiceActivityDetection of type boolean, defaulting to trueMany codecs and system are capable of detecting "silence" and changing their behavior in this case by doing things such as not transmitting any media. In many cases, such as when dealing with sounds other than spoken voice or emergency calling, it is desirable to be able to turn off this behavior. This option allows the application to provide information about whether it wishes this type of processing enabled or disabled.
enum RTCIdentityOption {
    "yes",
    "no",
    "ifconfigured"
};| Enumeration description | |
|---|---|
yes | An identity MUST be requested. | 
no | No identity is to be requested. | 
ifconfigured | The value "ifconfigured" means that an identity will be requested
          if either the user has configured an identity in the browser or if the
          setIdentityProvider() call has been made in JavaScript.
          As this is the default value, an identity will be requested if and
          only if the user has configured an IdP in some way. | 
The general operation of the RTCPeerConnection is described in [RTCWEB-JSEP].
Calling new  creates an RTCPeerConnection(configuration
        ) object.RTCPeerConnection
The configuration has the information to find and access the servers used by ICE. There may be multiple servers of each type and any TURN server also acts as a STUN server.
An  object has an associated
        ICE agent [ICE],
        RTCPeerConnection signaling state, ICE gathering state, and ICE
        connection state. These are initialized when the object is created.RTCPeerConnection
An  object has two associated
        stream sets. A local streams set,
        representing streams that are currently sent, and a remote streams set, representing streams
        that are currently received with this
        RTCPeerConnection object. The stream sets are
        initialized to empty sets when the
        RTCPeerConnection object is created.RTCPeerConnection
When the RTCPeerConnection() constructor
        is invoked, the user agent MUST run the following steps:
Validate the  argument by
            running the steps defined by the updateIce() method.RTCConfiguration
Let connection be a newly created 
             object.RTCPeerConnection
Create an ICE Agent as defined in [ICE] and let
            connection's RTCPeerConnection ICE Agent be
            that ICE Agent and provide it the the ICE servers list. The ICE Agent will proceed
            with gathering as soon as the ICE
            transports setting is not set to none. At this
            point the ICE Agent does not know how many ICE components it needs
            (and hence the number of candidates to gather), but it can make a
            reasonable assumption such as 2. As the
            RTCPeerConnection object gets more information, the
            ICE Agent can adjust the number of components.
Set connection's RTCPeerConnection
            signalingState to stable.
Set connection's RTCPeerConnection
            ice connection state to new.
Set connection's RTCPeerConnection
            ice gathering state to new.
Initialize an internal variable to represent a queue of
            operations with an empty set.
Return connection.
Once the RTCPeerConnection object has been initialized, for every
        call to createOffer, setLocalDescription,
        createAnswer and setRemoteDescription;
        execute the following steps:
Append an object representing the current call being handled
            (i.e. function name and corresponding arguments) to the
            operations array.
If the length of the operations array is exactly 1,
            execute the function from the front of the queue
            asynchronously.
When the asynchronous operation completes (either successfully
            or with an error), remove the corresponding object from the
            operations array. After removal, if the array is
            non-empty, execute the first object queued asynchronously and
            repeat this step on completion.
The general idea is to have only one among createOffer,
        setLocalDescription, createAnswer and
        setRemoteDescription executing at any given time. If
        subsequent calls are made while one of them is still executing, they
        are added to a queue and processed when the previous operation is fully
        completed. It is valid, and expected, for normal error handling
        procedures to be applied.
Additionally, during the lifetime of the RTCPeerConnection object, the following procedures are followed when an ICE event occurs:
If the RTCPeerConnection
            ice gathering state is new and the ICE transports setting is not
            set to none, the user agent MUST
            queue a task to start gathering ICE addresses and set the ice gathering state
            to gathering.
If the ICE Agent has found one or more candidate pairs for each MediaStreamTrack that forms a valid connection, the ICE connection state is changed to "connected".
When the ICE Agent finishes checking all candidate pairs, if at least one connection has been found for each MediaStreamTrack, the iceConnectionState is changed to "completed"; else the iceConnectionState is changed to "failed".
When the ICE Agent needs to notify the script about the candidate gathering progress, the user agent must queue a task to run the following steps:
Let connection be the
             object associated with this
            ICE Agent.RTCPeerConnection
If connection's RTCPeerConnection
            signalingState is closed, abort these steps.
If the intent of the ICE Agent is to notify the script that:
A new candidate is available.
Add the candidate to connection's
                localDescription and create a
                 object to represent the
                candidate. Let newCandidate be that object.RTCIceCandidate
The gathering process is done.
Set connection's ice gathering
                state to completed and let
                newCandidate be null.
Fire a icecandidate event named icecandidate with
            newCandidate at connection.
User agents negotiate the codec resolution, bitrate, and other media
        parameters. It is RECOMMENDED that user agents initially negotiate for
        the maximum resolution of a video stream. For streams that are then
        rendered (using a video element), it is RECOMMENDED that
        user agents renegotiate for a resolution that matches the rendered
        display size.
The word "components" in this context refers to an RTP media flow and does not have anything to do with how [ICE] uses the term "component".
When a user agent has reached the point where a
        MediaStream can be created to represent incoming
        components, the user agent MUST run the following steps:
Let connection be the
             expecting this media.RTCPeerConnection
Create a MediaStream object
            stream, to represent the incoming media stream.
Run the algorithm to represent an incoming component with a track for each incoming component.
The creation of new incoming
            MediaStreams may be triggered either by SDP
            negotiation or by the receipt of media on a given flow.
            
Queue a task to run the following substeps:
If the connection's RTCPeerConnection
                signalingState is closed, abort these
                steps.
Add stream to connection's remote streams set.
Fire a stream event named
                addstream with
                stream at the connection
                object.
When a user agent has negotiated media for a component that belongs
        to a media stream that is already represented by an existing
        MediaStream object, the user agent MUST associate
        the component with that MediaStream object.
When an  finds that a stream
        from the remote peer has been removed, the user agent MUST follow these
        steps:RTCPeerConnection
Let connection be the
             associated with the stream
            being removed.RTCPeerConnection
Let stream be the MediaStream
            object that represents the media stream being removed, if any. If
            there isn't one, then abort these steps.
By definition, stream is now ended.
A task is thus queued to update stream and fire an event.
Queue a task to run the following substeps:
If the connection's RTCPeerConnection
                signalingState is closed, abort these
                steps.
Remove stream from connection's remote streams set.
Fire a stream event named
                removestream with
                stream at the connection
                object.
The task source for the tasks listed in this section is the networking task source.
If something in the browser changes that causes the
         object to need to initiate a new
        session description negotiation, a RTCPeerConnectionnegotiationneeded event is fired at the
         object.RTCPeerConnection
In particular, if an  object is
        consuming a RTCPeerConnectionMediaStream on
        which a track is added, by, e.g., the addTrack()
        method being invoked, the  object
        MUST fire the "negotiationneeded" event. Removal of media components
        must also trigger "negotiationneeded".RTCPeerConnection
To prevent network sniffing from allowing a fourth party to establish a connection to a peer using the information sent out-of-band to the other peer and thus spoofing the client, the configuration information SHOULD always be transmitted using an encrypted connection.
[ Constructor (RTCConfiguration configuration)]
interface RTCPeerConnection : EventTarget  {
    void                  createOffer (RTCSessionDescriptionCallback successCallback, RTCPeerConnectionErrorCallback failureCallback, optional RTCOfferOptions options);
    void                  createAnswer (RTCSessionDescriptionCallback successCallback, RTCPeerConnectionErrorCallback failureCallback, optional RTCOfferAnswerOptions options);
    void                  setLocalDescription (RTCSessionDescription description, VoidFunction successCallback, RTCPeerConnectionErrorCallback failureCallback);
    readonly    attribute RTCSessionDescription? localDescription;
    void                  setRemoteDescription (RTCSessionDescription description, VoidFunction successCallback, RTCPeerConnectionErrorCallback failureCallback);
    readonly    attribute RTCSessionDescription? remoteDescription;
    readonly    attribute RTCSignalingState      signalingState;
    void                  updateIce (RTCConfiguration configuration);
    void                  addIceCandidate (RTCIceCandidate candidate, VoidFunction successCallback, RTCPeerConnectionErrorCallback failureCallback);
    readonly    attribute RTCIceGatheringState   iceGatheringState;
    readonly    attribute RTCIceConnectionState  iceConnectionState;
    RTCConfiguration      getConfiguration ();
    sequence<MediaStream> getLocalStreams ();
    sequence<MediaStream> getRemoteStreams ();
    MediaStream?          getStreamById (DOMString streamId);
    void                  addStream (MediaStream stream);
    void                  removeStream (MediaStream stream);
    void                  close ();
                attribute EventHandler           onnegotiationneeded;
                attribute EventHandler           onicecandidate;
                attribute EventHandler           onsignalingstatechange;
                attribute EventHandler           onaddstream;
                attribute EventHandler           onremovestream;
                attribute EventHandler           oniceconnectionstatechange;
};RTCPeerConnection| Parameter | Type | Nullable | Optional | Description | 
|---|---|---|---|---|
| configuration |  | ✘ | ✘ | 
iceConnectionState of type RTCIceConnectionState, readonly   The iceConnectionState
            attribute MUST return the state of the RTCPeerConnection ICE
            Agent ICE state.
iceGatheringState of type RTCIceGatheringState, readonly   The iceGatheringState
            attribute MUST return the gathering state of the RTCPeerConnection ICE
            Agent connection state.
localDescription of type RTCSessionDescription, readonly   , nullableThe localDescription
            attribute MUST return the 
            that was most recently passed to RTCSessionDescriptionsetLocalDescription(),
            plus any local candidates that have been generated by the ICE Agent
            since then.
A null object will be returned if the local description has not yet been set.
onaddstream of type EventHandler,            addstream, MUST be fired by
          all objects implementing the RTCPeerConnection
          interface. It is called any time a MediaStream is added
          by the remote peer. This will be fired only as a result of
          setRemoteDescription. Onnaddstream happens as early as
          possible after the setRemoteDescription. This callback
          does not wait for a given media stream to be accepted or rejected via
          SDP negotiation.onicecandidate of type EventHandler,            icecandidate, MUST be supported by
          all objects implementing the RTCPeerConnection
          interface.oniceconnectionstatechange of type EventHandler,            iceconnectionstatechange,
          MUST be fired by all objects implementing the
          RTCPeerConnection interface. It is called any
          time the iceConnectionState changes.onnegotiationneeded of type EventHandler,            negotiationneeded , MUST be supported
          by all objects implementing the RTCPeerConnection
          interface.onremovestream of type EventHandler,            removestream, MUST be
          fired by all objects implementing the
          RTCPeerConnection interface. It is called any
          time a MediaStream is removed by the remote peer. This
          will be fired only as a result of
          setRemoteDescription.onsignalingstatechange of type EventHandler,            signalingstatechange, MUST
          be supported by all objects implementing the
          RTCPeerConnection interface. It is called any
          time the readyState changes, i.e., from a call to
          setLocalDescription, a call to
          setRemoteDescription, or code. It does not fire for the
          initial state change into new.remoteDescription of type RTCSessionDescription, readonly   , nullableThe remoteDescription
            attribute MUST return the 
            that was most recently passed to RTCSessionDescriptionsetRemoteDescription(),
            plus any remote candidates that have been supplied via
            addIceCandidate()
            since then.
A null object will be returned if the remote description has not yet been set.
signalingState of type RTCSignalingState, readonly   The signalingState
            attribute MUST return the RTCPeerConnection
            object's RTCPeerConnection
            signaling state.
addIceCandidateThe addIceCandidate()
            method provides a remote candidate to the ICE Agent. In addition to
            being added to the remote description, connectivity checks will be
            sent to the new candidates as long as the ICE Transports setting is not
            set to none. This call will result in a change
            to the connection state of the ICE Agent, and may result in a
            change to media state if it results in different connectivity being
            established.
If the candidate parameter is malformed, throw a
            SyntaxError exception and abort these steps.
If the candidate is successfully applied, the user agent MUST queue a task to invoke successCallback.
If the candidate could not be successfully applied, the user
            agent MUST queue a task to invoke failureCallback with a
            DOMError object whose name attribute has
            the value TBD (TODO InvalidCandidate and InvalidMidIndex).
| Parameter | Type | Nullable | Optional | Description | 
|---|---|---|---|---|
| candidate |  | ✘ | ✘ | |
| successCallback | VoidFunction | ✘ | ✘ | |
| failureCallback |  | ✘ | ✘ | 
voidaddStreamAdds a new stream to the RTCPeerConnection.
When the addStream() method is invoked, the user agent MUST
            run the following steps:
Let connection be the
                 object on which the
                RTCPeerConnectionMediaStream, stream, is to be
                added.
If connection's RTCPeerConnection
                signalingState is closed, throw an
                InvalidStateError exception and abort these
                steps.
If stream is already in connection's local streams set, then abort these steps.
Add stream to connection's local streams set.
A stream could have contents that are inaccessible to the application. This can be due to being marked with a peerIdentity option or anything that would make a stream CORS cross-origin. These streams can be added to the local streams set but content MUST NOT be transmitted, with one exception.
A stream marked with the peerIdentity option can be transmitted if the RTCPeerConnection has successfully validated the identity of the peer to have the same identity as the value of the peerIdentity option on the stream.
All other streams that are not accessible to the application MUST NOT be sent to the peer, with silence (audio), black frames (video) or equivalently absent content being sent in place of stream content.
Note that this property can change over time.
If connection's RTCPeerConnection
                signalingState is stable, then fire a negotiationneeded event at
                connection.
| Parameter | Type | Nullable | Optional | Description | 
|---|---|---|---|---|
| stream | MediaStream | ✘ | ✘ | 
voidcloseWhen the RTCPeerConnection close() method is invoked, the
            user agent MUST run the following steps:
RTCPeerConnection object's RTCPeerConnection
              signalingState is closed, abort these steps.
              Destroy the RTCPeerConnection
                ICE Agent, abruptly ending any active ICE processing and
                any active streaming, and releasing any relevant resources
                (e.g. TURN permissions).
Set the object's RTCPeerConnection
                signalingState to closed.
voidcreateAnswerThe createAnswer method generates an [SDP] answer with the supported configuration for the session that is compatible with the parameters in the remote configuration. Like createOffer, the returned blob contains descriptions of the local MediaStreams attached to this RTCPeerConnection, the codec/RTP/RTCP options negotiated for this session, and any candidates that have been gathered by the ICE Agent. The options parameter may be supplied to provide additional control over the generated answer.
As an answer, the generated SDP will contain a specific configuration that, along with the corresponding offer, specifies how the media plane should be established. The generation of the SDP must follow the appropriate process for generating an answer.
Session descriptions generated by createAnswer must be immediately usable by setLocalDescription without generating an error if setLocalDescription is called from the successCallback function. Like createOffer, the returned description should reflect the current state of the system. The session descriptions MUST remain usable by setLocalDescription without causing an error until at least the end of the successCallback function. Calling this method is needed to get the ICE user name fragment and password.
An answer can be marked as provisional, as described in
            [RTCWEB-JSEP], by setting the type to
            "pranswer".
If the RTCPeerConnection is configured to generate
            Identity assertions, then the session description SHALL contain an
            appropriate assertion.
If this RTCPeerConnection object is closed before
            the SDP generation process completes, the USER agent MUST suppress
            the result and not call any of the result callbacks.
If the SDP generation process completed successfully, the user
            agent MUST queue a task to invoke successCallback with a
            newly created  object,
            representing the generated answer, as its argument.RTCSessionDescription
If the SDP generation process failed for any reason, the user
            agent MUST queue a task to invoke failureCallback with
            an DOMError object of type TBD as its argument.
| Parameter | Type | Nullable | Optional | Description | 
|---|---|---|---|---|
| successCallback |  | ✘ | ✘ | |
| failureCallback |  | ✘ | ✘ | |
| options |  | ✘ | ✔ | 
voidcreateOfferThe createOffer method generates a blob of SDP that contains an
            RFC 3264 offer with the supported configurations for the session,
            including descriptions of the local MediaStreams
            attached to this RTCPeerConnection, the codec/RTP/RTCP
            options supported by this implementation, and any candidates that
            have been gathered by the ICE Agent. The options parameter may
            be supplied to provide additional control over the offer generated.
            
As an offer, the generated SDP will contain the full set of capabilities supported by the session (as opposed to an answer, which will include only a specific negotiated subset to use); for each SDP line, the generation of the SDP must follow the appropriate process for generating an offer. In the event createOffer is called after the session is established, createOffer will generate an offer that is compatible with the current session, incorporating any changes that have been made to the session since the last complete offer-answer exchange, such as addition or removal of streams. If no changes have been made, the offer will include the capabilities of the current local description as well as any additional capabilities that could be negotiated in an updated offer.
Session descriptions generated by createOffer MUST be immediately usable by setLocalDescription without causing an error as long as setLocalDescription is called within the successCallback function. If a system has limited resources (e.g. a finite number of decoders), createOffer needs to return an offer that reflects the current state of the system, so that setLocalDescription will succeed when it attempts to acquire those resources. The session descriptions MUST remain usable by setLocalDescription without causing an error until at least end of the successCallback function. Calling this method is needed to get the ICE user name fragment and password.
If the RTCPeerConnection is configured to generate
            Identity assertions, then the session description SHALL contain an
            appropriate assertion.
If this RTCPeerConnection object is closed before
            the SDP generation process completes, the USER agent MUST suppress
            the result and not call any of the result callbacks.
If the SDP generation process completed successfully, the user
            agent MUST queue a task to invoke successCallback with a
            newly created  object,
            representing the generated offer, as its argument.RTCSessionDescription
If the SDP generation process failed for any reason, the user
            agent MUST queue a task to invoke failureCallback with
            an DOMError object of type TBD as its argument.
To Do: Discuss privacy aspects of this from a fingerprinting point of view - it's probably around as bad as access to a canvas :-)
| Parameter | Type | Nullable | Optional | Description | 
|---|---|---|---|---|
| successCallback |  | ✘ | ✘ | |
| failureCallback |  | ✘ | ✘ | |
| options |  | ✘ | ✔ | 
voidgetConfigurationReturns a  object representing the current configuration of this RTCConfiguration object.RTCPeerConnection
When this method is call, the user agent MUST construct new  object to be returned, and initialize it using the ICE Agent's ICE transports setting and ICE servers list.RTCConfiguration
RTCConfigurationgetLocalStreamsReturns a sequence of MediaStream objects
            representing the streams that are currently sent with this
             object.RTCPeerConnection
The getLocalStreams()
            method MUST return a new sequence that represents a snapshot of all
            the MediaStream objects in this
             object’s local streams set. The conversion from the
            streams set to the sequence, to be returned, is user agent defined
            and the order does not have to stable between calls.RTCPeerConnection
sequence<MediaStream>getRemoteStreamsReturns a sequence of MediaStream objects
            representing the streams that are currently received with this
             object.RTCPeerConnection
The getRemoteStreams()
            method MUST return a new sequence that represents a snapshot of all
            the MediaStream objects in this
             object’s remote streams set. The conversion from
            the streams set to the sequence, to be returned, is user agent
            defined and the order does not have to stable between calls.RTCPeerConnection
sequence<MediaStream>getStreamByIdIf a MediaStream object, with an
            id
            equal to streamId, exists in this
             object’s stream sets
            (local streams set or remote streams set), then the RTCPeerConnectiongetStreamById()
            method MUST return that MediaStream object. The
            method MUST return null if no stream matches the
            streamId argument.
For this method to make sense, we need to make sure that ids are unique within the two stream sets of a RTCPeerConnection. This is not the case today when a peer re-adds a stream that is received. Two different stream instances will now have the same id at both peers; one in the remote stream set and one in the local stream set.
One way to resolve this is to not allow re-adding a stream instance that is received (guard on id). If an application really needs this functionality it's really easy to make a clone of the stream, which will give it a new id, and send the clone.
| Parameter | Type | Nullable | Optional | Description | 
|---|---|---|---|---|
| streamId | DOMString | ✘ | ✘ | 
MediaStream, nullableremoveStreamRemoves the given stream from the
            .RTCPeerConnection
When the other peer stops sending a stream in this manner, a
            removestream event is
            fired at the  object.RTCPeerConnection
When the removeStream() method is invoked, the user agent
            MUST run the following steps:
Let connection be the
                 object on which the
                RTCPeerConnectionMediaStream, stream, is to be
                removed.
If connection's RTCPeerConnection
                signalingState is closed, throw an
                InvalidStateError exception.
If stream is not in connection's local streams set, then abort these steps.
Remove stream from connection's local streams set.
If connection's RTCPeerConnection
                signalingState is stable, then fire a negotiationneeded event at
                connection.
| Parameter | Type | Nullable | Optional | Description | 
|---|---|---|---|---|
| stream | MediaStream | ✘ | ✘ | 
voidsetLocalDescriptionThe setLocalDescription()
            method instructs the  to apply
            the supplied RTCPeerConnection as the local
            description.RTCSessionDescription
This API changes the local media state. In order to successfully
            handle scenarios where the application wants to offer to change
            from one media format to a different, incompatible format, the
             must be able to
            simultaneously support use of both the old and new local
            descriptions (e.g. support codecs that exist in both descriptions)
            until a final answer is received, at which point the
            RTCPeerConnection can fully adopt the new local
            description, or rollback to the old description if the remote side
            denied the change.RTCPeerConnection
ISSUE: how to indicate to rollback?
To Do: specify what parts of the SDP can be changed between the createOffer and setLocalDescription
When the method is invoked, the user agent must follow the processing model described by the following list:
If this  object's
                signaling
                state is RTCPeerConnectionclosed, the user agent MUST throw an
                InvalidStateError exception and abort this
                operation.
If a local description contains a different set of ICE credentials, then the ICE Agent MUST trigger an ICE restart. When ICE restarts, the gathering state will be changed back to "gathering", if it was not already gathering. If the IceConnectionState was "completed", it will be changed back to "connected".
If the process to apply the
                 argument fails for
                any reason, then user agent must queue a task runs the
                following steps:RTCSessionDescription
Let connection be the
                     object on with this
                    method was invoked.RTCPeerConnection
If connection's signaling state
                    is closed, then abort these steps.
If the reason for the failure is:
The content of the
                         argument is
                        invalid or the RTCSessionDescriptiontype is
                        wrong for the current signaling
                        state of connection.
Let errorType be
                        InvalidSessionDescriptionError.
The  is a
                        valid description but cannot be applied at the media
                        layer.RTCSessionDescription
TODO ISSUE - next few points are probably wrong. Make sure to check this in setRemote too.
This can happen, e.g., if there are insufficient resources to apply the SDP. The user agent MUST then rollback as necessary if the new description was partially applied when the failure occurred.
If rollback was not necessary or was completed
                        successfully, let errorType be
                        IncompatibleSessionDescriptionError. If
                        rollback was not possible, let errorType be
                        InternalError and set
                        connection's signaling
                        state to closed.
Invoke the failureCallback with an
                    DOMError object, whose name
                    attribute is errorType, as its argument.
If the  argument is
                applied successfully, then user agent must queue a task runs
                the following steps:RTCSessionDescription
Let connection be the
                     object on with this
                    metod was invoked.RTCPeerConnection
If connection's signaling state
                    is closed, then abort these steps.
Set connection's description attribute
                    (localDescription or
                    remoteDescription depending on the
                    setting operation) to the
                     argument.RTCSessionDescription
If the local description was set,
                    connection's ice gathering
                    state is new, and the local description
                    contains media, then set connection's ice gathering
                    state to gathering.
If the local description was set with content that
                    caused an ICE restart, then set connection's
                    ice
                    gathering state to gathering.
Set connection's signalingState accordingly.
Fire a simple event named signalingstatechange
                    at connection.
Queue a new task that, if connection's
                    signalingState is
                    not closed, invokes the
                    successCallback.
| Parameter | Type | Nullable | Optional | Description | 
|---|---|---|---|---|
| description |  | ✘ | ✘ | |
| successCallback | VoidFunction | ✘ | ✘ | |
| failureCallback |  | ✘ | ✘ | 
voidsetRemoteDescriptionThe setRemoteDescription()
            method instructs the  to apply
            the supplied RTCPeerConnection as the
            remote offer or answer. This API changes the local media state.RTCSessionDescription
When the method is invoked, the user agent must follow the processing model of setLocalDescription(),
           with the following additional conditions:
If an a=identity attribute is present in the
                session description, the browser validates the identity
                assertion..  Identity validation completes asynchronously
                and does not block the completion of
                setRemoteDescription, unless there is a target peer identity.
If the "peerIdentity" constraint is applied to the
                , this establishes a target peer identity.
                Alternatively, if the RTCPeerConnection has
                previously authenticated the identity of the peer (that is,
                there is a current value for RTCPeerConnectionpeerIdentity),
                then this also establishes a target peer identity.
If there is a target peer
                identity, then setRemoteDescription fails
                unless it contains an identity assertion that matches the target peer identity.  The
                RTCPeerConnection MAY be closed if the validated
                peer identity does not match the target peer identity.  [[TODO:
                determine if it is possible at this point to back out the
                change.  Seems unlikely.]]
| Parameter | Type | Nullable | Optional | Description | 
|---|---|---|---|---|
| description |  | ✘ | ✘ | |
| successCallback | VoidFunction | ✘ | ✘ | |
| failureCallback |  | ✘ | ✘ | 
voidupdateIceThe updateIce method updates the ICE Agent process of gathering local candidates and pinging remote candidates.
This call may result in a change to the state of the ICE Agent, and may result in a change to media state if it results in connectivity being established.
When the updateIce()
            method is invoked, the user MUST run the following steps to
            process the  dictionary:RTCConfiguration
If the iceTransports member is present, let its value be the ICE Agent's ICE transports setting.
If the iceTransports member was omitted and the ICE Agent's ICE transports setting is unset, set the ICE Agent's ICE transports setting to the iceTransports dictionary member default value.
If the iceServers dictionary
                member is present, but its value is an empty list, then throw
                an InvalidAccessError and abort these steps. If
                the list, on the other hand, has elements, each element must be
                validated by running the following sub-steps:
Let server be the current list element.
If the server.urls dictionary member is
                    omitted or an empty list, then throw an
                    InvalidAccessError and abort these steps.
If server.urls is a string, let urls be a list consisting of just that string. Otherwise, let urls refer to the server.urls list.
For each url in urls, parse the url and
                    obtain scheme name. If the parsing fails or if
                    scheme name is not implemented by the browser,
                    throw a SyntaxError and abort these steps.
If scheme name is "turn" and either of the
                    dictionary members server.username or
                    server.credential are omitted, then throw an
                    InvalidAccessError and abort these steps.
After passing the validation, let the iceServers dictionary member be the ICE Agent's ICE servers list.
If a new list of servers replaces the ICE Agent's existing
                  ICE servers list, no action will taken until the 
                  's  ice gathering
                  state transitions to RTCPeerConnectiongathering. If a script
                  wants this to happen immediately, it should do an ICE restart.
              
              
If the iceServers dictionary
                member was omitted, and the ICE Agent's ICE servers list is unset, throw an
                InvalidAccessError and abort these steps.
| Parameter | Type | Nullable | Optional | Description | 
|---|---|---|---|---|
| configuration |  | ✘ | ✘ | 
voidA Window object has a strong reference to any
         objects created from the
        constructor whose global object is that RTCPeerConnectionWindow object.
enum RTCSignalingState {
    "stable",
    "have-local-offer",
    "have-remote-offer",
    "have-local-pranswer",
    "have-remote-pranswer",
    "closed"
};| Enumeration description | |
|---|---|
stable | There is no offeranswer exchange in progress. This is also the initial state in which case the local and remote descriptions are empty. | 
have-local-offer | A local description, of type "offer", has been successfully applied. | 
have-remote-offer | A remote description, of type "offer", has been successfully applied. | 
have-local-pranswer | A remote description of type "offer" has been successfully applied and a local description of type "pranswer" has been successfully applied. | 
have-remote-pranswer | A local description of type "offer" has been successfully applied and a remote description of type "pranswer" has been successfully applied. | 
closed | The connection is closed. | 
The non-normative peer state transitions are: 
An example set of transitions might be:
Caller transition:
stablehave-local-offerhave-remote-pranswerstableclosedCallee transition:
stablehave-remote-offerhave-local-pranswerstableclosedenum RTCIceGatheringState {
    "new",
    "gathering",
    "complete"
};| Enumeration description | |
|---|---|
new | The object was just created, and no networking has occurred yet. | 
gathering | The ICE engine is in the process of gathering candidates for this RTCPeerConnection. | 
complete | The ICE engine has completed gathering. Events such as adding a new interface or a new TURN server will cause the state to go back to gathering. | 
enum RTCIceConnectionState {
    "new",
    "checking",
    "connected",
    "completed",
    "failed",
    "disconnected",
    "closed"
};| Enumeration description | |
|---|---|
new | The ICE Agent is gathering addresses and/or waiting for remote candidates to be supplied. | 
checking | The ICE Agent has received remote candidates on at least one component, and is checking candidate pairs but has not yet found a connection. In addition to checking, it may also still be gathering. | 
connected | The ICE Agent has found a usable connection for all components but is still checking other candidate pairs to see if there is a better connection. It may also still be gathering. | 
completed | The ICE Agent has finished gathering and checking and found a connection for all components. Open issue: it is not clear how the non controlling ICE side knows it is in the state. | 
failed | The ICE Agent is finished checking all candidate pairs and failed to find a connection for at least one component. Connections may have been found for some components. | 
disconnected | Liveness checks have failed for one or more components. This is
          more aggressive than failed, and may trigger
          intermittently (and resolve itself without action) on a flaky
          network. | 
closed | The ICE Agent has shut down and is no longer responding to STUN requests. | 
States take either the value of any component or all components, as outlined below:
checking occurs if ANY component has received a
          candidate and can start checkingconnected occurs if ALL components have established
          a working connectioncompleted occurs if ALL components have finalized
          the running of their ICE processesfailed occurs if ANY component has given up trying
          to connectdisconnected occurs if ANY component has failed
          liveness checksclosed occurs only if
          RTCPeerConnection.close() has been called.If a component is discarded as a result of signaling (e.g. RTCP mux
        or BUNDLE), the state may advance directly from checking
        to completed.
An example transition might look like:
newnew, remote candidates received):
          checkingchecking, found usable connection):
          connectedchecking, gave up): failedconnected, finished all checks):
          completedcompleted, lost connectivity):
          disconnectednewclosedThe non-normative ICE state transitions are: 
callback RTCPeerConnectionErrorCallback = void (DOMError error);RTCPeerConnectionErrorCallback Parameterserror of type DOMErrorErrors are indicated in two ways: exceptions and objects passed to
        error callbacks. Exceptions are thrown to indicate invalid state and
        other programming errors. For example when a method is called when the
         is in an invalid state, or a
        state in which that particular method is not allowed to be executed. In
        all other cases, an error object MUST be provided to the error
        callback.RTCPeerConnection
interface RTCSdpError : DOMError {
    readonly    attribute long sdpLineNumber;
};sdpLineNumber of type long, readonly   RTCSessionDescription
          at which the error was encountered.Ask the DOM team to extend their list with the following errors. The error names and their descriptions are directly copied from the old RTCErrorName enum and might need some adjustment before being added to the public list of errors.
The RTCSdpType enum describes the type of an
         instance.RTCSessionDescription
enum RTCSdpType {
    "offer",
    "pranswer",
    "answer"
};| Enumeration description | |
|---|---|
offer | 
             An RTCSdpType of "offer" indicates that a description should be treated as an [SDP] offer.  | 
pranswer | 
             An RTCSdpType of "pranswer" indicates that a description should be treated as an [SDP] answer, but not a final answer. A description used as an SDP "pranswer" may be applied as a response to a SDP offer, or an update to a previously sent SDP "pranswer".  | 
answer | 
             An RTCSdpType of "answer" indicates that a description should be treated as an [SDP] final answer, and the offer-answer exchange should be considered complete. A description used as an SDP answer may be applied as a response to an SDP offer or as an update to a previously sent SDP "pranswer".  | 
dictionary RTCSessionDescriptionInit {
    RTCSdpType type;
    DOMString  sdp;
};
[ Constructor (optional RTCSessionDescriptionInit descriptionInitDict)]
interface RTCSessionDescription {
                attribute RTCSdpType? type;
                attribute DOMString?  sdp;
    serializer = {attribute};
};RTCSessionDescriptionRTCSessionDescription()
          constructor takes an optional dictionary argument,
          descriptionInitDict, whose content is used to initialize
          the new RTCSessionDescription object. If a
          dictionary key is not present in descriptionInitDict, the
          corresponding attribute will be initialized to null. If the
          constructor is run without the dictionary argument, all attributes
          will be initialized to null. This class is a future extensible
          carrier for the data contained in it and does not perform any
          substantive processing.| Parameter | Type | Nullable | Optional | Description | 
|---|---|---|---|---|
| descriptionInitDict |  | ✘ | ✔ | 
sdp of type DOMString,            , nullabletype of type RTCSdpType,            , nullableInstances of this interface are serialized as a map with entries for each of the serializable attributes.
RTCSessionDescriptionInit Memberssdp of type DOMStringtype of type RTCSdpTypecallback RTCSessionDescriptionCallback = void (RTCSessionDescription sdp);RTCSessionDescriptionCallback Parameterssdp of type RTCSessionDescriptionThis class is a future extensible carrier for the data contained in it and does not perform any substantive processing.
dictionary RTCIceCandidateInit {
    DOMString      candidate;
    DOMString      sdpMid;
    unsigned short sdpMLineIndex;
};
[ Constructor (optional RTCIceCandidateInit candidateInitDict)]
interface RTCIceCandidate {
                attribute DOMString?      candidate;
                attribute DOMString?      sdpMid;
                attribute unsigned short? sdpMLineIndex;
    serializer = {attribute};
};RTCIceCandidateRTCIceCandidate() constructor
          takes an optional dictionary argument, candidateInitDict,
          whose content is used to initialize the new
          RTCIceCandidate object. If a dictionary key is
          not present in candidateInitDict, the corresponding
          attribute will be initialized to null. If the constructor is run
          without the dictionary argument, all attributes will be initialized
          to null.| Parameter | Type | Nullable | Optional | Description | 
|---|---|---|---|---|
| candidateInitDict |  | ✘ | ✔ | 
candidate of type DOMString,            , nullablesdpMLineIndex of type unsigned short,            , nullablesdpMid of type DOMString,            , nullableInstances of this interface are serialized as a map with entries for each of the serializable attributes.
RTCIceCandidateInit Memberscandidate of type DOMStringsdpMLineIndex of type unsigned shortsdpMid of type DOMStringThe icecandidate event of the RTCPeerConnection uses
        the  interface.RTCPeerConnectionIceEvent
Firing an
         event named
        e with an RTCPeerConnectionIceEvent
        candidate means that an event with the name e,
        which does not bubble (except where otherwise stated) and is not
        cancelable (except where otherwise stated), and which uses the
        RTCIceCandidateRTCPeerConnectionIceEvent interface with the
        candidate attribute set to the new ICE candidate, MUST be
        created and dispatched at the given target.
dictionary RTCPeerConnectionIceEventInit : EventInit {
    RTCIceCandidate candidate;
};
[ Constructor (DOMString type, RTCPeerConnectionIceEventInit eventInitDict)]
interface RTCPeerConnectionIceEvent : Event {
    readonly    attribute RTCIceCandidate candidate;
};RTCPeerConnectionIceEvent| Parameter | Type | Nullable | Optional | Description | 
|---|---|---|---|---|
| type | DOMString | ✘ | ✘ | |
| eventInitDict |  | ✘ | ✘ | 
candidate of type RTCIceCandidate, readonly   The candidate attribute is the
             object with the new ICE
            candidate that caused the event.RTCIceCandidate
RTCPeerConnectionIceEventInit Memberscandidate of type RTCIceCandidateTODO
The Peer-to-peer Data API lets a web application send and receive generic application data peer-to-peer. The API for sending and receiving data models the behavior of WebSockets [WEBSOCKETS-API].
The Peer-to-peer data API extends the
       interface as described below.RTCPeerConnection
partial interface RTCPeerConnection {
    RTCDataChannel createDataChannel ([TreatNullAs=EmptyString] DOMString label, optional RTCDataChannelInit dataChannelDict);
                attribute EventHandler ondatachannel;
};ondatachannel of type EventHandler,            datachannel, MUST be supported by all
        objects implementing the RTCPeerConnection
        interface.createDataChannelCreates a new  object with the
          given label. The RTCDataChannel dictionary
          can be used to configure properties of the underlying channel such as
           data reliability.RTCDataChannelInit
When the createDataChannel()
          method is invoked, the user agent MUST run the following steps.
If the  object’s RTCPeerConnectionRTCPeerConnection
              signalingState is closed, throw an
              InvalidStateError exception and abort these
              steps.
Let channel be a newly created
               object.RTCDataChannel
Initialize channel's label attribute to the value
              of the first argument.
If the second (dictionary) argument is present, set
              channel's ordered, maxPacketLifeTime,
              maxRetransmits,
              protocol,
              negotiated
              and id attributes
              to the values of their corresponding dictionary members (if
              present in the dictionary).
If both the maxPacketLifeTime
              and maxRetransmits
              attributes are set (not null), then throw a
              SyntaxError exception and abort these steps.
If an attribute, either maxPacketLifeTime
              or maxRetransmits, has
              been set to indicate unreliable mode, and that value exceeds the
              maximum value supported by the user agent, the value must be set
              to the user agents maximum value.
If id attribute
              is uninitialized (not set via the dictionary), initialize it to a
              value generated by the user agent, according to the WebRTC
              DataChannel Protocol specification, and skip to the next step.
              Otherwise, if the value of the id attribute is taken by an
              existing , throw a
              RTCDataChannelResourceInUse exception and abort these steps.
Return channel and continue the following steps in the background.
Create channel's associated underlying data transport and configure it according to the relevant properties of channel.
| Parameter | Type | Nullable | Optional | Description | 
|---|---|---|---|---|
| label | DOMString | ✘ | ✘ | |
| dataChannelDict |  | ✘ | ✔ | 
RTCDataChannelThe  interface represents a
      bi-directional data channel between two peers. A
      RTCDataChannel is created via a factory method on an
      RTCDataChannel object. The messages sent between
      the browsers are described in [RTCWEB-DATA] and [RTCWEB-DATA-PROTOCOL]. RTCPeerConnection
There are two ways to establish a connection with
      . The first way is to simply create a
      RTCDataChannel at one of the peers with the
      RTCDataChannelnegotiated
       dictionary member unset or set to
      its default value false. This will announce the new channel in-band and
      trigger a RTCDataChannelInit with the corresponding
      RTCDataChannelEvent object at the other peer. The second
      way is to let the application negotiate the
      RTCDataChannel. To do this, create a
      RTCDataChannel object with the RTCDataChannelnegotiated
       dictionary member set to true, and
      signal out-of-band (e.g. via a web server) to the other side that it
      should create a corresponding RTCDataChannelInit with the
      RTCDataChannelnegotiated
       dictionary member set to true and
      the same RTCDataChannelInitid. This will
      connect the two separately created 
      objects. The second way makes it possible to create channels with
      asymmetric properties and to create channels in a declarative way by
      specifying matching RTCDataChannelids.
Each  has an associated
      underlying data transport that is used to transport actual
      data to the other peer. The transport properties of the underlying
      data transport, such as in order delivery settings and reliability
      mode, are configured by the peer as the channel is created. The
      properties of a channel cannot change after the channel has been created.
      The actual wire protocol between the peers is specified by the WebRTC
      DataChannel Protocol specification (TODO: reference needed).RTCDataChannel
A  can be configured to operate in
      different reliability modes. A reliable channel ensures that the data is
      delivered at the other peer through retransmissions. An unreliable
      channel is configured to either limit the number of retransmissions
      (RTCDataChannelmaxRetransmits ) or
      set a time during which transmissions (including retransmissions) are allowed (maxPacketLifeTime).
      These properties can not be used simultaneously and an attempt to do so
      will result in an error. Not setting any of these properties results in a
      reliable channel.
A , created with RTCDataChannelcreateDataChannel() or
      dispatched via a , MUST initially
      be in the RTCDataChannelEventconnecting state. When the
       object’s underlying data
      transport is ready, the user agent MUST announce the RTCDataChannelRTCDataChannel as
      open.
When the user agent is to announce
      a RTCDataChannel as open, the user agent MUST queue a
      task to run the following steps:
If the associated  object's
          RTCPeerConnectionRTCPeerConnection
          signalingState is closed, abort these steps.
Let channel be the 
          object to be announced.RTCDataChannel
Set channel's readyState attribute to
          open.
Fire a simple event named open at channel.
When an underlying data transport is to be announced (the other
      peer created a channel with negotiated unset or set
      to false), the user agent of the peer that did not initiate the creation
      process MUST queue a task to run the following steps:
If the associated  object's
          RTCPeerConnectionRTCPeerConnection
          signalingState is closed, abort these steps.
Let channel be a newly created
           object.RTCDataChannel
Let configuration be an information bundle received from the other peer as a part of the process to establish the underlying data transport described by the WebRTC DataChannel Protocol specification.
Initialize channel's label, ordered, maxPacketLifeTime,
          maxRetransmits,
          protocol,
          negotiated and
          id attributes to their
          corresponding values in configuration.
Set channel's readyState attribute to
          connecting.
Fire a datachannel event named datachannel with channel
          at the  object.RTCPeerConnection
An  object's underlying data
      transport may be torn down in a non-abrupt manner by running the
      closing procedure. When
      that happens the user agent MUST, unless the procedure was initiated by
      the RTCDataChannelclose() method,
      queue a task that sets the object's readyState attribute to
      closing. This will eventually render the data transport closed.
When a  object's underlying data
      transport has been closed, the
      user agent MUST queue a task to run the following steps:RTCDataChannel
Let channel be the 
          object whose transport
          was closed.RTCDataChannel
Set channel's readyState attribute to
          closed.
If the transport was closed with an error, fire an NetworkError event at channel.
Fire a simple event named close at
          channel.
dictionary RTCDataChannelInit {
    boolean        ordered = true;
    unsigned short maxPacketLifeTime;
    unsigned short maxRetransmits;
    DOMString      protocol = "";
    boolean        negotiated = false;
    unsigned short id;
};
interface RTCDataChannel : EventTarget {
    readonly    attribute DOMString           label;
    readonly    attribute boolean             ordered;
    readonly    attribute unsigned?           maxPacketLifeTime;
    readonly    attribute unsigned?           maxRetransmits;
    readonly    attribute DOMString           protocol;
    readonly    attribute boolean             negotiated;
    readonly    attribute unsigned short      id;
    readonly    attribute RTCDataChannelState readyState;
    readonly    attribute unsigned long       bufferedAmount;
                attribute EventHandler        onopen;
                attribute EventHandler        onerror;
                attribute EventHandler        onclose;
    void close ();
                attribute EventHandler        onmessage;
                attribute DOMString           binaryType;
    void send (DOMString data);
    void send (Blob data);
    void send (ArrayBuffer data);
    void send (ArrayBufferView data);
};binaryType of type DOMString,            The binaryType attribute
          MUST, on getting, return the value to which it was last set. On
          setting, the user agent must set the IDL attribute to the new value.
          When a  object is created, the
          RTCDataChannelbinaryType
          attribute MUST be initialized to the string "blob".
This attribute controls how binary data is exposed to scripts. See the [WEBSOCKETS-API] for more information.
bufferedAmount of type unsigned long, readonly   The bufferedAmount
          attribute MUST return the number of bytes of application data (UTF-8
          text and binary data) that have been queued using send() but that, as of the last
          time the event loop started executing a task, had not yet been
          transmitted to the network. (This thus includes any text sent during
          the execution of the current task, regardless of whether the user
          agent is able to transmit text asynchronously with script execution.)
          This does not include framing overhead incurred by the protocol, or
          buffering done by the operating system or network hardware. If the
          channel is closed, this attribute's value will only increase with
          each call to the send() method (the attribute does
          not reset to zero once the channel closes).
id of type unsigned short, readonly   The RTCDataChannel.id attribute
          returns the id for this  . The id
          was either assigned by the user agent at channel creation time or
          selected by the script. The attribute MUST return the value to which
          it was set when the RTCDataChannel was
          created.RTCDataChannel
label of type DOMString, readonly   The RTCDataChannel.label
          attribute represents a label that can be used to distinguish this
           object from other
          RTCDataChannel objects. The attribute MUST return
          the value to which it was set when the
          RTCDataChannel object was created.RTCDataChannel
maxPacketLifeTime of type unsigned, readonly   , nullableThe RTCDataChannel.maxPacketLifeTime
          attribute returns the length of the time window (in milliseconds)
          during which transmissions and retransmissions may occur in
          unreliable mode, or null if unset. The attribute MUST be initialized
          to null by default and MUST return the value to which it was set when
          the  was created.RTCDataChannel
maxRetransmits of type unsigned, readonly   , nullableThe RTCDataChannel.maxRetransmits
          attribute returns the maximum number of retransmissions that are
          attempted in unreliable mode, or null if unset. The attribute MUST be
          initialized to null by default and MUST return the value to which it
          was set when the  was created.RTCDataChannel
negotiated of type boolean, readonly   The RTCDataChannel.negotiated
          attribute returns true if this  was
          negotiated by the application, or false otherwise. The attribute MUST
          be initialized to false by default and MUST return the value to which
          it was set when the RTCDataChannel was
          created.RTCDataChannel
onclose of type EventHandler,            close, MUST be supported by all
        objects implementing the RTCDataChannel
        interface.onerror of type EventHandler,            error, MUST be supported by all
        objects implementing the RTCDataChannel
        interface.onmessage of type EventHandler,            message ,MUST be supported by
        all objects implementing the RTCDataChannel
        interface.onopen of type EventHandler,            open, MUST be supported by all
        objects implementing the RTCDataChannel
        interface.ordered of type boolean, readonly   The RTCDataChannel.ordered
          attribute returns true if the  is
          ordered, and false if other of order delivery is allowed. The
          attribute MUST be initialized to true by default and MUST return the
          value to which it was set when the RTCDataChannel
          was created.RTCDataChannel
protocol of type DOMString, readonly   The RTCDataChannel.protocol
          attribute returns the name of the sub-protocol used with this
           if any, or the empty string
          otherwise. The attribute MUST be initialized to the empty string by
          default and MUST return the value to which it was set when the
          RTCDataChannel was created.RTCDataChannel
readyState of type RTCDataChannelState, readonly   The RTCDataChannel.readyState
          attribute represents the state of the RTCDataChannel
          object. It MUST return the value to which the user agent last set it
          (as defined by the processing model algorithms).
closeCloses the . It may be called
          regardless of whether the RTCDataChannel object
          was created by this peer or the remote peer.RTCDataChannel
When the RTCDataChannel
          close() method is called, the user agent MUST run the
          following steps:
Let channel be the
               object which is about to be
              closed.RTCDataChannel
If channel's readyState is
              closing or closed, then abort these
              steps.
Set channel's readyState attribute to
              closing.
If the closing procedure
              has not started yet, start it.
voidsendRun the steps described by the send() algorithm with argument
          type string object.
| Parameter | Type | Nullable | Optional | Description | 
|---|---|---|---|---|
| data | DOMString | ✘ | ✘ | 
voidsendRun the steps described by the send() algorithm with argument
          type Blob object.
| Parameter | Type | Nullable | Optional | Description | 
|---|---|---|---|---|
| data | Blob | ✘ | ✘ | 
voidsendRun the steps described by the send() algorithm with argument
          type ArrayBuffer object.
| Parameter | Type | Nullable | Optional | Description | 
|---|---|---|---|---|
| data | ArrayBuffer | ✘ | ✘ | 
voidsendRun the steps described by the send() algorithm with argument
          type ArrayBufferView object.
| Parameter | Type | Nullable | Optional | Description | 
|---|---|---|---|---|
| data | ArrayBufferView | ✘ | ✘ | 
voidRTCDataChannelInit Membersid of type unsigned shortOverrides the default selection of id for this channel.
maxPacketLifeTime of type unsigned shortLimits the time during which the channel will transmit or retransmit data if not acknowledged. This value may be clamped if it exceeds the maximum value supported by the user agent.
maxRetransmits of type unsigned shortLimits the number of times a channel will retransmit data if not successfully delivered. This value may be clamped if it exceeds the maximum value supported by the user agent..
negotiated of type boolean, defaulting to falseThe default value of false tells the user agent to announce the
          channel in-band and instruct the other peer to dispatch a
          corresponding  object. If set to
          true, it is up to the application to negotiate the channel and create
          a RTCDataChannel object with the same
          RTCDataChannelid at the other
          peer.
ordered of type boolean, defaulting to trueIf set to false, data is allowed to be delivered out of order. The default value of true, guarantees that data will be delivered in order.
protocol of type DOMString, defaulting to ""Subprotocol name used for this channel.
The send() method is
      overloaded to handle different data argument types. When any version of
      the method is called, the user agent MUST run the following steps:
Let channel be the 
          object on which data is to be sent.RTCDataChannel
If channel’s readyState attribute
          is connecting, throw an InvalidStateError
          exception and abort these steps.
Execute the sub step that corresponds to the type of the methods argument:
string object:
Let data be the result of converting the argument
              object to a sequence of Unicode characters and increase the
              bufferedAmount
              attribute by the number of bytes needed to express
              data as UTF-8.
Blob object:
Let data be the raw data represented by the
              Blob object and increase the bufferedAmount
              attribute by the size of data, in bytes.
ArrayBuffer object:
Let data be the data stored in the buffer described
              by the ArrayBuffer object and increase the
              bufferedAmount
              attribute by the length of the ArrayBuffer in
              bytes.
ArrayBufferView object:
Let data be the data stored in the section of the
              buffer described by the ArrayBuffer object that the
              ArrayBufferView object references and increase the
              bufferedAmount
              attribute by the length of the ArrayBufferView in
              bytes.
If channel’s underlying data transport is not
          established yet, or if the closing procedure has
          started, then abort these steps.
Attempt to send data on channel’s underlying data transport; if the data cannot be sent, e.g. because it would need to be buffered but the buffer is full, the user agent MUST abruptly close channel’s underlying data transport with an error.
enum RTCDataChannelState {
    "connecting",
    "open",
    "closing",
    "closed"
};| Enumeration description | |
|---|---|
connecting | 
           The user agent is attempting to establish the underlying data
          transport. This is the initial state of a
            | 
open | 
           The underlying data transport is established and
          communication is possible. This is the initial state of a
            | 
closing | 
           The   | 
closed | 
           The underlying data transport has been   | 
The datachannel event
      uses the  interface.RTCDataChannelEvent
Firing a datachannel event named
      e with a 
      channel means that an event with the name e, which
      does not bubble (except where otherwise stated) and is not cancelable
      (except where otherwise stated), and which uses the
      RTCDataChannel interface with the RTCDataChannelEventchannel attribute set to
      channel, MUST be created and dispatched at the given
      target.
dictionary RTCDataChannelEventInit : EventInit {
    RTCDataChannel channel;
};
[ Constructor (DOMString type, RTCDataChannelEventInit eventInitDict)]
interface RTCDataChannelEvent : Event {
    readonly    attribute RTCDataChannel channel;
};RTCDataChannelEvent| Parameter | Type | Nullable | Optional | Description | 
|---|---|---|---|---|
| type | DOMString | ✘ | ✘ | |
| eventInitDict |  | ✘ | ✘ | 
channel of type RTCDataChannel, readonly   The channel attribute
          represents the  object associated
          with the event.RTCDataChannel
RTCDataChannelEventInit Memberschannel of type RTCDataChannelTODO
A  object MUST not be garbage
      collected if itsRTCDataChannel
readyState
          is connecting and at least one event listener is
          registered for open events, message events,
          error events, or close events.
readyState
          is open and at least one event listener is registered
          for message events, error events, or
          close events.
readyState
          is closing and at least one event listener is registered
          for error events, or close events.
underlying data transport is established and data is queued to be transmitted.
In order to send DTMF (phone keypad) values across an
    , the user agent needs to know which
    RTCPeerConnectionMediaStreamTrack on which
     will carry the DTMF. This section
    describes an interface on RTCPeerConnection to
    associate DTMF capability with a RTCPeerConnectionMediaStreamTrack for
    that . Details of how DTMF is sent to
    the other peer are described in [RTCWEB-AUDIO].RTCPeerConnection
The Peer-to-peer DTMF API extends the
       interface as described below.RTCPeerConnection
partial interface RTCPeerConnection {
    RTCDTMFSender createDTMFSender (MediaStreamTrack track);
};createDTMFSenderThe createDTMFSender() method creates an RTCDTMFSender
          that references the given MediaStreamTrack. The MediaStreamTrack MUST
          be an element of a MediaStream that's currently in the
           object's local streams set; if not, throw an
          RTCPeerConnectionInvalidParameter exception and abort these steps.
| Parameter | Type | Nullable | Optional | Description | 
|---|---|---|---|---|
| track | MediaStreamTrack | ✘ | ✘ | 
RTCDTMFSenderAn  is created by calling the
      RTCDTMFSendercreateDTMFSender() method on an
      . This constructs an object that
      exposes the functions required to send DTMF on the given
      RTCPeerConnectionMediaStreamTrack.
[NoInterfaceObject]
interface RTCDTMFSender {
    readonly    attribute boolean          canInsertDTMF;
    void insertDTMF (DOMString tones, optional long duration, optional long interToneGap);
    readonly    attribute MediaStreamTrack track;
                attribute EventHandler     ontonechange;
    readonly    attribute DOMString        toneBuffer;
    readonly    attribute long             duration;
    readonly    attribute long             interToneGap;
};canInsertDTMF of type boolean, readonly   The canInsertDTMF
          attribute MUST indicate if the  is
          capable of sending DTMF.RTCDTMFSender
duration of type long, readonly   The duration attribute
          MUST return the current tone duration value. This value will be the
          value last set via the insertDTMF() method, or
          the default value of 100 ms if insertDTMF() was
          called without specifying the duration.
interToneGap of type long, readonly   The interToneGap
          attribute MUST return the current value of the between-tone gap. This
          value will be the value last set via the
          insertDTMF() method, or the default value of 70
          ms if insertDTMF() was called without specifying
          the interToneGap.
ontonechange of type EventHandler,            This event handler uses the
           interface to return the
          character for each tone as it is played out. See
          RTCDTMFToneChangeEvent for details.RTCDTMFToneChangeEvent
toneBuffer of type DOMString, readonly   The toneBuffer
          attribute MUST return a list of the tones remaining to be played out.
          For the syntax, content, and interpretation of this list, see
          insertDTMF.
track of type MediaStreamTrack, readonly   The track attribute MUST return the
          MediaStreamTrack given as argument to the
          createDTMFSender() method.
insertDTMFAn  object’s RTCDTMFSenderinsertDTMF() method
          is used to send DTMF tones.
The tones parameter is treated as a series of characters. The characters 0 through 9, A through D, #, and * generate the associated DTMF tones. The characters a to d are equivalent to A to D. The character ',' indicates a delay of 2 seconds before processing the next character in the tones parameter. Unrecognized characters are ignored.
The duration parameter indicates the duration in ms to use for each character passed in the tones parameters. The duration cannot be more than 6000 ms or less than 40 ms. The default duration is 100 ms for each tone.
The interToneGap parameter indicates the gap between tones. It MUST be at least 30 ms. The default value is 70 ms.
The browser MAY increase the duration and interToneGap times to cause the times that DTMF start and stop to align with the boundaries of RTP packets but it MUST not increase either of them by more than the duration of a single RTP audio packet.
ISSUE: How are invalid values handled?
When the insertDTMF() method is invoked, the
          user agent MUST run the following steps:
MediaStreamTrack is not
            connected to the associated RTCPeerConnection,
            return.canInsertDTMF
            attribute is false, return.toneBuffer attribute to
            the value of the tones argument, the value of the
            duration
            attribute to the duration argument if specified, and the
            value of the interToneGap to the
            interToneGap argument, if specified.toneBuffer is an empty
            string, return.toneBuffer is an
                empty string, fire an event named tonechange with an
                empty string at the RTCDTMFSender object
                and abort these steps.toneBuffer and let
                that character be tone.duration ms on the
                associated RTP media stream, using the appropriate codec.duration +
                interToneGap ms
                from now that runs the steps labelled Playout
                task.tonechange with a
                string consisting of tone at the
                RTCDTMFSender object.Calling insertDTMF() with an empty
          tones parameter can be used to cancel all tones queued to play after
          the currently playing tone.
| Parameter | Type | Nullable | Optional | Description | 
|---|---|---|---|---|
| tones | DOMString | ✘ | ✘ | |
| duration | long | ✘ | ✔ | |
| interToneGap | long | ✘ | ✔ | 
voidThe tonechange event uses the
       interface.RTCDTMFToneChangeEvent
Firing a tonechange event named
      e with a DOMString tone means
      that an event with the name e, which does not bubble (except
      where otherwise stated) and is not cancelable (except where otherwise
      stated), and which uses the 
      interface with the RTCDTMFToneChangeEventtone attribute set to
      tone, MUST be created and dispatched at the given target.
dictionary RTCDTMFToneChangeEventInit : EventInit {
    DOMString tone;
};
[ Constructor (DOMString type, RTCDTMFToneChangeEventInit eventInitDict)]
interface RTCDTMFToneChangeEvent : Event {
    readonly    attribute DOMString tone;
};RTCDTMFToneChangeEvent| Parameter | Type | Nullable | Optional | Description | 
|---|---|---|---|---|
| type | DOMString | ✘ | ✘ | |
| eventInitDict |  | ✘ | ✘ | 
tone of type DOMString, readonly   The tone
          attribute contains the character for the tone that has just begun
          playout (see insertDTMF()). If the value is the
          empty string, it indicates that the previous tone has completed
          playback.
RTCDTMFToneChangeEventInit Memberstone of type DOMStringTODO
The basic statistics model is that the browser maintains a set of
      statistics referenced by a selector. The
      selector may, for example, be a MediaStreamTrack. For a
      track to be a valid selector, it must be a member of a
      MediaStream that is sent or received by the
       object on which the stats request
      was issued. The calling Web application provides the selector to the
      RTCPeerConnectiongetStats() method
      and the browser emits (in the JavaScript) a set of statistics that it
      believes is relevant to the selector.
The statistics returned are designed in such a way that repeated
      queries can be linked by the  id dictionary member. Thus, a Web application can
      make measurements over a given time period by requesting measurements at
      the beginning and end of that period.RTCStats
The Statistics API extends the 
      interface as described below.RTCPeerConnection
partial interface RTCPeerConnection {
    void getStats (MediaStreamTrack? selector, RTCStatsCallback successCallback, RTCPeerConnectionErrorCallback failureCallback);
};getStatsGathers stats for the given selector and reports the result asynchronously.
When the getStats() method is
          invoked, the user agent MUST queue a task to run the following
          steps:
If the  object's RTCPeerConnectionRTCPeerConnection
              signalingState is closed, throw an
              InvalidStateError exception.
Return, but continue the following steps in the background.
Let selectorArg be the methods first argument.
If selectorArg is an invalid selector, the user agent MUST queue a task to invoke the failure callback (the method's third argument).
Start gathering the stats indicated by selectorArg.
              In case selectorArg is null, stats MUST be gathered
              for the whole  object.RTCPeerConnection
When the relevant stats have been gathered, queue a task to
              invoke the success callback (the method's second argument) with a
              new  object, representing the
              gathered stats, as its argument.RTCStatsReport
| Parameter | Type | Nullable | Optional | Description | 
|---|---|---|---|---|
| selector | MediaStreamTrack | ✔ | ✘ | |
| successCallback |  | ✘ | ✘ | |
| failureCallback |  | ✘ | ✘ | 
voidcallback RTCStatsCallback = void (RTCStatsReport report);RTCStatsCallback Parametersreport of type RTCStatsReportA  representing the gathered
          stats.RTCStatsReport
The getStats()
      method delivers a successful result in the form of a
       object. A
      RTCStatsReport object represents a map between
      strings, identifying the inspected objects (RTCStats.id), and their corresponding
      RTCStatsReport objects.RTCStats
An  may be composed of several
      RTCStatsReport objects, each reporting stats for one
      underlying object that the implementation thinks is relevant for the
      selector. One achieves the total for the
      selector by summing over all the stats of a
      certain type; for instance, if a RTCStatsMediaStreamTrack is carried
      by multiple SSRCs over the network, the
       may contain one RTCStatsReportRTCStats
      object per SSRC (which can be distinguished by the value of the "ssrc"
      stats attribute).
interface RTCStatsReport {
    getter RTCStats (DOMString id);
};RTCStatsGetter to retrieve the  objects that
          this stats report is composed of.RTCStats
The set of supported property names [WEBIDL] is defined as the
          ids of all the  objects that has been
          generated for this stats report. The order of the property names is
          left to the user agent.RTCStats
| Parameter | Type | Nullable | Optional | Description | 
|---|---|---|---|---|
| id | DOMString | ✘ | ✘ | 
getterAn  dictionary represents the stats
      gathered by inspecting a specific object relevant to a selector. The RTCStats
      dictionary is a base type that specifies as set of default attributes,
      such as timestamp and type. Specific stats are added by extending the
      RTCStats dictionary.RTCStats
Note that while stats names are standardized, any given implementation may be using experimental values or values not yet known to the Web application. Thus, applications MUST be prepared to deal with unknown stats.
Statistics need to be synchronized with each other in order to yield
      reasonable values in computation; for instance, if "bytesSent" and
      "packetsSent" are both reported, they both need to be reported over the
      same interval, so that "average packet size" can be computed as "bytes /
      packets" - if the intervals are different, this will yield errors. Thus
      implementations MUST return synchronized values for all stats in a
       object.RTCStats
dictionary RTCStats {
    DOMHiResTimeStamp timestamp;
    RTCStatsType      type;
    DOMString         id;
};RTCStats Membersid of type DOMStringA unique id that is
          associated with the object that was inspected to produce this
           object. Two RTCStats
          objects, extracted from two different
          RTCStats objects, MUST have the same id if
          they were produced by inspecting the same underlying object. User
          agents are free to pick any format for the id as long as it meets the
          requirements above.RTCStatsReport
timestamp of type DOMHiResTimeStampThe timestamp,
          of type DOMHiResTimeStamp [HIGHRES-TIME], associated
          with this object. The time is relative to the UNIX epoch (Jan 1,
          1970, UTC).
type of type RTCStatsTypeThe type of this object.
The type attribute
          MUST be initialized to the name of the most specific type this
           dictionary represents.RTCStats
enum RTCStatsType {
    "inbound-rtp",
    "outbound-rtp"
};| Enumeration description | |
|---|---|
inbound-rtp | Inbound RTP. | 
outbound-rtp | Outbund RTP. | 
dictionary RTCRTPStreamStats : RTCStats {
    DOMString ssrc;
    DOMString remoteId;
};RTCRTPStreamStats MembersremoteId of type DOMStringThe remoteId can be used to look up the corresponding
           object that represents stats reported by
          the other peer.RTCStats
ssrc of type DOMString...
dictionary RTCInboundRTPStreamStats : RTCRTPStreamStats {
    unsigned long packetsReceived;
    unsigned long bytesReceived;
};RTCInboundRTPStreamStats MembersbytesReceived of type unsigned long...
packetsReceived of type unsigned long...
dictionary RTCOutboundRTPStreamStats : RTCRTPStreamStats {
    unsigned long packetsSent;
    unsigned long bytesSent;
};RTCOutboundRTPStreamStats MembersbytesSent of type unsigned long...
packetsSent of type unsigned long...
Consider the case where the user is experiencing bad sound and the application wants to determine if the cause of it is packet loss. The following example code might be used:
var baselineReport, currentReport; var selector = pc.getRemoteStreams()[0].getAudioTracks()[0]; pc.getStats(selector, function (report) { baselineReport = report; }); // ... wait a bit setTimeout(function () { pc.getStats(selector, function (report) { currentReport = report; processStats(); }); }, aBit); function processStats() { // compare the elements from the current report with the baseline for each (var now in currentReport) { if (now.type != "outbund-rtp") continue; // get the corresponding stats from the baseline report base = baselineReport[now.id]; if (base) { remoteNow = currentReport[now.remoteId]; remoteBase = baselineReport[base.remoteId]; var packetsSent = now.packetsSent - base.packetsSent; var packetsReceived = remoteNow.packetsReceived - remoteBase.packetsReceived; // if fractionLost is > 0.3, we have probably found the culprit var fractionLost = (packetsSent - packetsReceived) / packetsSent; } } }
WebRTC offers and answers (and hence the channels established by
       objects) can be authenticated by
      using a web-based Identity Provider (IdP). The idea is that the entity
      sending the offer/answer acts as the Authenticating Party (AP) and obtains
      an identity assertion from the IdP which it attaches to the offer/answer.
      The consumer of the offer/answer (i.e., the
      RTCPeerConnection on which
      RTCPeerConnectionsetRemoteDescription() is called) acts as the Relying Party
      (RP) and verifies the assertion.
The interaction with the IdP is designed to decouple the browser from any particular identity provider; the browser need only know how to load the IdP's JavaScript—which is deterministic from the IdP's identity—and the generic protocol for requesting and verifying assertions. The IdP provides whatever logic is necessary to bridge the generic protocol to the IdP's specific requirements. Thus, a single browser can support any number of identity protocols, including being forward compatible with IdPs which did not exist at the time the browser was written. The generic protocol details are described in [RTCWEB-SECURITY-ARCH]. This document specifies the procedures required to instantiate the IdP proxy, request identity assertions, and consume the results.
In order to communicate with the IdP, the browser instantiates an isolated interpreted context, effectively an invisible IFRAME. The initial contents of the context are loaded from a URI derived from the IdP's domain name, as described in [RTCWEB-SECURITY-ARCH].
For purposes of generating assertions, the IdP shall be chosen as follows:
setIdentityProvider() method has been called,
          the IdP provided shall be used.setIdentityProvider() method has not been
          called, then the browser can use an IdP configured into the
          browser.In order to verify assertions, the IdP domain name and protocol are
        taken from the domain and protocol fields of
        the identity assertion.
The browser creates an IdP proxy by loading an isolated, invisible
        IFRAME with HTML content from the IdP URI. The URI for the IdP is a
        well-known URI formed from the domain
 and protocol
        fields, as specified in [RTCWEB-SECURITY-ARCH].
When an IdP proxy is requiured, the browser performs the following steps:
sandbox attribute is set to
          "allow-forms allow-scripts allow-same-origin" to limit the
          capabilities available to the IdP. The browser MUST prevent the IdP
          proxy from navigating the browsing context to a different location.
          The browser MUST prevent the IdP proxy from interacting with the user
          (this includes, in particular, popup windows and user dialogs).MessageChannel [webmessaging] within the context of
          the IdP proxy and assigns one port from the channel to a variable
          named rtcwebIdentityPort on the window. This
          message channel forms the basis of communication between the browser
          and the IdP proxy.  Since it is an essential security property of the
          web sandbox that a page is unable to insert objects into content from
          another origin, this ensures that the IdP proxy can trust that
          messages originating from window.rtcwebIdentityPort are
          from RTCPeerConnection and not some other page. This
          protection ensures that pages from other origins are unable to
          instantiate IdP proxies and obtain identity assertions.RTCPeerConnection that it is ready by sending a "READY"
          message to the message channel port [RTCWEB-SECURITY-ARCH]. Once
          this message is received by the RTCPeerConnection, the
          IdP is considered ready to receive requests to generate or verify
          identity assertions.[TODO: This is not sufficient unless we expect the IdP to protect this information. Otherwise, the a=identity information can be copied from a session with "good" properties to any other session with the same fingerprint information. Since we want to reuse credentials, that would be bad.] The identity mechanism MUST provide an indication to the remote side of whether it requires the stream contents to be protected. Implementations MUST have an user interface that indicates the different cases and identity for these.
The identity assertion request process involves the following steps:
RTCPeerConnection instantiates an IdP proxy as
        described in Identity
        Provider Selection section and waits
        for the IdP to signal that it is ready.RTCPeerConnection desires to be bound to the user's
        identity.RTCPeerConnection over the message channel.RTCPeerConnection MAY store the identity assertion
        for use with future offers or answers.createOffer() or createAnswer(), then the
        assertion is inserted in the offer/answer SDP.The format and contents of the messages that are exchanged are described in detail in [RTCWEB-SECURITY-ARCH].
The IdP proxy can return an "ERROR" response.  If an error is
      encountered, the browser MUST generate
      an idpassertionerror
      event.  No "a=identity" attribute is added to SDP as a result.
The browser SHOULD limit the time that it will allow for this process. This includes both the loading of the IdP proxy and the identity assertion generation. Failure to do so potentially causes the corresponding operation to take an indefinite amount of time. This timer can be cancelled when the IdP produces a response. The timer running to completion can be treated as equivalent to an error from the IdP.
An IdP could respond to a request to generate an identity assertion with a "LOGINNEEDED" error. This indicates that the site does not have the necessary information available to it (such as cookies) to authorize the creation of an identity assertion.
The "LOGINNEEDED" response includes a URL for a page where the
        authorization process can be completed.  This URL is exposed to the
        application through the loginUrl attribute
        of the idpassertionerror event.
        This URL might be to a page where a user is able to enter their (IdP)
        username and password, or otherwise provide any information the IdP
        needs to authorize a assertion request.
An application can load the login URL in an IFRAME or popup; the resulting page then provides the user with an opportunity to provide information necessary to complete the authorization process.
Once the authorization process is complete, the page loaded in the IFRAME or popup sends a message using postMessage [webmessaging] to the page that loaded it (through the window.opener attribute for popups, or through window.parent for pages loaded in an IFRAME). The message MUST be the DOMString "LOGINDONE". This message informs the application that another attempt at generating an identity assertion is likely to be successful.
Identity assertion validation happens
      when setRemoteDescription
      is invoked on .  The process runs
      asynchronously, meaning that validation of an identity assertion does not
      block the completion of RTCPeerConnectionsetRemoteDescription.
The identity assertion request process involves the following steps:
RTCPeerConnection instantiates an IdP proxy as
        described in  Identity
        Provider Selection section  and waits
        for the IdP to signal that it is ready.RTCPeerConnection over the message channel.RTCPeerConnection validates that the fingerprint
        provided by the IdP in the validation response matches the certificate
        fingerprint that is, or will be, used for communications.  This is either by:
          RTCPeerConnection validates that the domain portion
        of the identity matches the domain of the IdP as described in [RTCWEB-SECURITY-ARCH].RTCPeerConnection stores the assertion in the
        peerIdentity
        attribute and raises a simple event
        named peeridentity at itself.  The assertion
        information to be displayed MUST contain the domain name of the IdP as
        provided in the assertion.The IdP might fail to validate the identity assertion by providing an "ERROR" response to the validation request. Validation can also fail due to the additional checks performed by the browser. In both cases, the process terminates and no identity information is exposed to the application or the user.
The browser MUST raise an idpvalidationerror event if
      validation of an identity assertion fails for any reason.
If the "peerIdentity" constraint is applied to the
      RTCPeerConnection, any error MUST
      cause setRemoteDescription
      to fail.
The browser SHOULD limit the time that it will allow for this process. This includes both the loading of the IdP proxy and the identity assertion validation. Failure to do so potentially causes the corresponding operation to take an indefinite amount of time. This timer can be cancelled when the IdP produces a response. The timer running to completion can be treated as equivalent to an error from the IdP.
It is possible that different values for the "a=identity" attribute is provided at a media level in SDP. A browser MAY either choose to treat this as an error or ignore the attribute. If multiple different assertions are validated, then they MUST produce identical identity values.
The format and contents of the messages that are exchanged are described in detail in [RTCWEB-SECURITY-ARCH].
The Identity API extends the 
      interface as described below.RTCPeerConnection
partial interface RTCPeerConnection {
    void setIdentityProvider (DOMString provider, optional DOMString protocol, optional DOMString username);
    void getIdentityAssertion ();
    readonly    attribute RTCIdentityAssertion? peerIdentity;
                attribute EventHandler          onidentityresult;
                attribute EventHandler          onpeeridentity;
                attribute EventHandler          onidpassertionerror;
                attribute EventHandler          onidpvalidationerror;
};onidentityresult of type EventHandler,            identityresult, MUST be fired by all
        objects implementing the RTCPeerConnection
        interface.  This event is fired when an identity assertion is
        successfully generated.  Note: this event is fired when an identity
        assertion is generated during the creation of an offer or answer.onidpassertionerror of type EventHandler,            idpassertionerror MUST be
        fired when an IdP encounters an error in generating an identity
        assertion.onidpvalidationerror of type EventHandler,            idvalidationperror MUST be
        fired when an IdP encounters an error in validating an identity
        assertion.onpeeridentity of type EventHandler,            peeridentity MUST be fired when a
        peer identity from a peer is successfully validated.peerIdentity of type RTCIdentityAssertion, readonly   , nullableContains the peer identity assertion information if an identity assertion was provided and verified. Once this value is set to a non-null value, it cannot change.
getIdentityAssertionInitiates the process of obtaining an identity assertion.
          Applications need not make this call. It is merely intended to allow
          them to start the process of obtaining identity assertions before a
          call is initiated. If an identity is needed, either because the
          browser has been configured with a default identity provider or
          because the setIdentityProvider() method was called,
          then an identity will be automatically requested when an offer or
          answer is created.
When getIdentityAssertion is invoked, queue a task to
          run the following steps:
If the connection's RTCPeerConnection
              signalingState is closed, abort these steps.
Request an identity assertion from the IdP.
voidsetIdentityProviderSets the identity provider to be used for a given
          RTCPeerConnection object. Applications need not make
          this call; if the browser is already configured for an IdP, then that
          configured IdP will be used to get an assertion.
When the setIdentityProvider()
          method is invoked, the user agent MUST run the following steps:
If the connection's RTCPeerConnection
              signalingState is closed, throw an
              InvalidStateError exception and abort these
              steps.
Set the current identity provider values to the triplet
              (provider, protocol,
              username).
If any identity provider value has changed, discard any stored identity assertion.
Identity provider information is not used until an identity
          assertion is required, either in response to a call to
          getIdentityAssertion, or the need to generate SDP with
          either createOffer or createAnswer.
| Parameter | Type | Nullable | Optional | Description | 
|---|---|---|---|---|
| provider | DOMString | ✘ | ✘ | |
| protocol | DOMString | ✘ | ✔ | |
| username | DOMString | ✘ | ✔ | 
voiddictionary RTCIdentityAssertion {
    DOMString idp;
    DOMString name;
};RTCIdentityAssertion Membersidp of type DOMStringA domain name representing the identity provider.
name of type DOMStringAn RFC5322-conformant [RFC5322] representation of the verified peer identity. This identity will have been verified via the procedures described in [RTCWEB-SECURITY-ARCH].
The RTCIdentiytEvent is raised when an IdP
      produces an identity assertion.
[NoInterfaceObject]
interface RTCIdentityEvent : Event {
                attribute DOMString assertion;
};assertion of type DOMString,            A string containing the encoded identity assertion (the information that would be added to the "a=identity" line in SDP [RTCWEB-SECURITY-ARCH]).
The RTCIdentityErrorEvent is raised when an
      IdP fails to successfully produce an identity assertion.
[NoInterfaceObject]
interface RTCIdentityErrorEvent : Event {
                attribute DOMString  idp;
                attribute DOMString  protocol;
                attribute DOMString? loginUrl;
};idp of type DOMString,            loginUrl of type DOMString,            , nullableprotocol of type DOMString,            The identity system is designed so that applications need not take any special action in order for users to generate and verify identity assertions; if a user has configured an IdP into their browser, then the browser will automatically request/generate assertions and the other side will automatically verify them and display the results. However, applications may wish to exercise tighter control over the identity system as shown by the following examples.
This example shows how to configure the identity provider and protocol.
pc.setIdentityProvider("example.com", "default", "alice@example.com");
This example shows how to consume identity assertions inside a Web application.
pc.onpeeridentity = function(e) { console.log("IdP= " + e.target.peerIdentity.idp + " identity=" + e.target.peerIdentity.name); };
The MediaStream interface, as defined in the
      [GETUSERMEDIA] specification, typically represents a stream of data of
      audio and/or video. A MediaStream may be extended to
      represent a stream that either comes from or is sent to a remote node (and
      not just the local camera, for instance). The extensions required to
      enable this capability on the MediaStream object will be
      described in this section. How the media is transmitted to the peer is
      described in [RTCWEB-RTP], [RTCWEB-AUDIO],
      [RTCWEB-VIDEO], and [RTCWEB-TRANSPORT]. 
A MediaStream as defined in [GETUSERMEDIA] may contain
      zero or more MediaStreamTrack objects. A
      MediaStreamTrack sent to another peer will appear as one and
      only one MediaStreamTrack to the recipient. A peer is
      defined as a user agent that supports this specification.
Channels are the smallest unit considered in the
      MediaStream specification. Channels are intended to be
      encoded together for transmission as, for instance, an RTP payload type.
      All of the channels that a codec needs to encode jointly MUST be in the
      same MediaStreamTrack and the codecs SHOULD be able to
      encode, or discard, all the channels in the track.
The concepts of an input and output to a given
      MediaStream apply in the case of MediaStream
      objects transmitted over the network as well. A
      MediaStream created by an
       object (described later in this
      document) will take as input the data received from a remote peer.
      Similarly, a RTCPeerConnectionMediaStream from a local source, for instance a
      camera via [GETUSERMEDIA], will have an output that represents what is
      transmitted to a remote peer if the object is used with an
       object.RTCPeerConnection
The concept of duplicating MediaStream objects as
      described in [GETUSERMEDIA] is also applicable here. This feature can
      be used, for instance, in a video-conferencing scenario to display the
      local video from the user’s camera and microphone in a local monitor,
      while only transmitting the audio to the remote peer (e.g. in response to
      the user using a "video mute" feature). Combining tracks from different
      MediaStream objects into a new
      MediaStream is useful in certain situations.
In this document, we only specify aspects of the
      following objects that are relevant when used along with an
      . Please refer to the original
      definitions of the objects in the [GETUSERMEDIA] document for general
      information on using RTCPeerConnectionMediaStream and
      MediaStreamTrack.
The id attribute
        specified in MediaStream returns an id that is unique to
        this stream, so that streams can be recognized after they are sent
        through the RTCPeerConnection API.
When a MediaStream is
        created to represent a stream obtained from a remote peer, the
        id
        attribute is initialized from information provided by the remote
        source.
The id of a MediaStream object is
        unique to the source of the stream, but that does not mean it is not
        possible to end up with duplicates. For example, a locally generated
        stream could be sent from one user agent to a remote peer using
         and then sent back to the
        original user agent in the same manner, in which case the original user
        agent will have multiple streams with the same id (the
        locally-generated one and the one received from the remote peer).RTCPeerConnection
A new media track may be associated with an existing
        MediaStream. For example, if a remote peer adds a
        new MediaStreamTrack object to a
        MediaStream that is being sent over an
        , this is observed on the local
        user agent. If this happens for the reason exemplified, or for any
        other reason than the RTCPeerConnectionaddTrack()
        method being invoked locally on a MediaStream or
        tracks being added as the stream is created (i.e. the stream is
        initialized with tracks), the user agent MUST run the following
        steps:
Let stream be the target
            MediaStream object.
Represent component with track: Run the following steps to create a track representing the incoming component:
Create a MediaStreamTrack object
                track to represent the component.
Initialize track’s kind
                attribute to "audio" or "video"
                depending on the media type of the incoming component.
Initialize track’s id
                attribute to the component track id.
Initialize track’s label
                attribute to "remote audio" or "remote
                video" depending on the media type of the incoming
                component.
Initialize track’s readyState
                attribute to muted.
Add track to stream’s track set.
Fire a track event named addtrack
            with the newly created MediaStreamTrack object
            at stream.
An existing media track may also be disassociated from a
        MediaStream. If this happens for any other reason
        than the removeTrack()
        method being invoked locally on a MediaStream or
        the stream being destroyed, the user agent MUST run the following
        steps:
Let stream be the target
            MediaStream object.
Let track be the MediaStreamTrack
            object representing the media component about to be removed.
Remove track from stream’s track set.
Fire a track event named removetrack
            with track at stream.
The event source for the onended event in the networked
        case is the  object.RTCPeerConnection
A MediaStreamTrack object’s reference to its
      MediaStream in the non-local media source case (an RTP
      source, as is the case for a MediaStream received over an
      ) is always strong.RTCPeerConnection
When a track belongs to a MediaStream that comes
      from a remote peer and the remote peer has permanently stopped sending
      data the ended event MUST be fired on the track, as
      specified in [GETUSERMEDIA].
ISSUE: How do you know when it has stopped? This seems like an SDP question, not a media-level question.
A track in a MediaStream, received with an
      , MUST have its
      RTCPeerConnectionreadyState attribute [GETUSERMEDIA] set to
      muted until media data arrives.
In addition, a MediaStreamTrack has its
      readyState set to muted on the remote peer if
      the local user agent disables the corresponding
      MediaStreamTrack in the
      MediaStream that is being sent. When the addstream
      event triggers on an , all
      RTCPeerConnectionMediaStreamTrack objects in the resulting
      MediaStream are muted until media data can be read
      from the RTP source.
ISSUE: How do you know when it has been disabled? This seems like an SDP question, not a media-level question.
The addstream
      and removestream events use the
       interface.MediaStreamEvent
Firing a
      stream event named e with a
      MediaStream stream means that an event
      with the name e, which does not bubble (except where otherwise
      stated) and is not cancelable (except where otherwise stated), and which
      uses the  interface with the
      MediaStreamEventstream attribute
      set to stream, MUST be created and dispatched at the
      given target.
dictionary MediaStreamEventInit : EventInit {
    MediaStream stream;
};
[ Constructor (DOMString type, MediaStreamEventInit eventInitDict)]
interface MediaStreamEvent : Event {
    readonly    attribute MediaStream? stream;
};MediaStreamEvent| Parameter | Type | Nullable | Optional | Description | 
|---|---|---|---|---|
| type | DOMString | ✘ | ✘ | |
| eventInitDict |  | ✘ | ✘ | 
stream of type MediaStream, readonly   , nullableThe stream attribute
          represents the MediaStream object associated with
          the event.
MediaStreamEventInit Membersstream of type MediaStreamTODO
This section is non-normative.
When two peers decide they are going to set up a connection to each other, they both go through these steps. The STUN/TURN server configuration describes a server they can use to get things like their public IP address or to set up NAT traversal. They also have to send data for the signaling channel to each other using the same out-of-band mechanism they used to establish that they were going to communicate in the first place.
var signalingChannel = new SignalingChannel(); var configuration = { "iceServers": [{ "url": "stun:stun.example.org" }] }; var pc; // call start() to initiate function start() { pc = new RTCPeerConnection(configuration); // send any ice candidates to the other peer pc.onicecandidate = function (evt) { if (evt.candidate) signalingChannel.send(JSON.stringify({ "candidate": evt.candidate })); }; // let the "negotiationneeded" event trigger offer generation pc.onnegotiationneeded = function () { pc.createOffer(localDescCreated, logError); } // once remote stream arrives, show it in the remote video element pc.onaddstream = function (evt) { remoteView.src = URL.createObjectURL(evt.stream); }; // get a local stream, show it in a self-view and add it to be sent navigator.getUserMedia({ "audio": true, "video": true }, function (stream) { selfView.src = URL.createObjectURL(stream); pc.addStream(stream); }, logError); } function localDescCreated(desc) { pc.setLocalDescription(desc, function () { signalingChannel.send(JSON.stringify({ "sdp": pc.localDescription })); }, logError); } signalingChannel.onmessage = function (evt) { if (!pc) start(); var message = JSON.parse(evt.data); if (message.sdp) pc.setRemoteDescription(new RTCSessionDescription(message.sdp), function () { // 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), function () {}, logError); }; function logError(error) { log(error.name + ": " + error.message); }
This example shows the more complete functionality.
TODOThis example shows how to create a
         object and perform the offer/answer
        exchange required to connect the channel to the other peer. The
        RTCDataChannel is used in the context of a simple
        chat application and listeners are attached to monitor when the channel
        is ready, messages are received and when the channel is closed.RTCDataChannel
This example uses the negotiationneeded
        event to initiate the offer/answer dialog. The exact behavior
        surrounding the negotiationneeded event is not specified
        in detail at the moment. This example can hopefully help to drive that
        discussion. An assumption made in this example is that the event only
        triggers when a new negotiation should be started. This means that an
        action (such as addStream()) that normally would have fired the
        negotiationneeded event will not do so during an ongoing
        offer/answer dialog.
var signalingChannel = new SignalingChannel(); var configuration = { "iceServers": [{ "url": "stun:stun.example.org" }] }; var pc; var channel; // call start(true) to initiate function start(isInitiator) { pc = new RTCPeerConnection(configuration); // send any ice candidates to the other peer pc.onicecandidate = function (evt) { if (evt.candidate) signalingChannel.send(JSON.stringify({ "candidate": evt.candidate })); }; // let the "negotiationneeded" event trigger offer generation pc.onnegotiationneeded = function () { pc.createOffer(localDescCreated, logError); } if (isInitiator) { // create data channel and setup chat channel = pc.createDataChannel("chat"); setupChat(); } else { // setup chat on incoming data channel pc.ondatachannel = function (evt) { channel = evt.channel; setupChat(); }; } } function localDescCreated(desc) { pc.setLocalDescription(desc, function () { signalingChannel.send(JSON.stringify({ "sdp": pc.localDescription })); }, logError); } signalingChannel.onmessage = function (evt) { if (!pc) start(false); var message = JSON.parse(evt.data); if (message.sdp) pc.setRemoteDescription(new RTCSessionDescription(message.sdp), function () { // 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), function () {}, logError); }; function setupChat() { channel.onopen = function () { // e.g. enable send button enableChat(channel); }; channel.onmessage = function (evt) { showChatMessage(evt.data); }; } function sendChatMessage(msg) { channel.send(msg); } function logError(error) { log(error.name + ": " + error.message); }
Editors' Note: This example flow needs to be discussed on the list and is likely wrong in many ways.
This shows an example of one possible call flow between two browsers. This does not show the procedure to get access to local media or every callback that gets fired but instead tries to reduce it down to only show the key events and messages.
      
Examples assume that pc is a connected RTCPeerConnection, and track is an audio track on that connection.
Sending the DTMF signal "1234" with 500 ms duration per tone:
var sender = pc.createDTMFSender(track); if (sender.canInsertDTMF) { var duration = 500; sender.insertDTMF("1234", duration); } else log("DTMF function not available");
Send the DTMF signal "1234", and light up the active key using
      lightKey(key) while the tone is playing (assuming that
      lightKey("") will darken all the keys):
var sender = pc.createDTMFSender(track); sender.ontonechange = function (e) { if (!e.tone) return; // light up the key when playout starts lightKey(e.tone); // turn off the light after tone duration setTimeout(lightKey, sender.duration, ""); }; sender.insertDTMF("1234");
Send a 1-second "1" tone followed by a 2-second "2" tone:
var sender = pc.createDTMFSender(track); sender.ontonechange = function (e) { if (e.tone == "1") sender.insertDTMF("2", 2000); }; sender.insertDTMF("1", 1000);
It is always safe to append to the tone buffer. This example appends before any tone playout has started as well as during playout.
var sender = pc.createDTMFSender(track); sender.insertDTMF("123"); // append more tones to the tone buffer before playout has begun sender.insertDTMF(sender.toneBuffer + "456"); sender.ontonechange = function (e) { if (e.tone == "1") // append more tones when playout has begun sender.insertDTMF(sender.toneBuffer + "789"); };
Send the DTMF signal "123" and abort after sending "2".
var sender = pc.createDTMFSender(track); sender.ontonechange = function (e) { if (e.tone == "2") // empty the buffer to not play any tone after "2" sender.insertDTMF(""); }; sender.insertDTMF("123");
This section is non-normative.
The following events fire on 
    objects:RTCDataChannel
| Event name | Interface | Fired when... | 
|---|---|---|
open
           | 
          Event
           | 
          
            The  object's underlying data
            transport has been established (or re-established).
           | 
        
MessageEvent
           | 
          Event
           | 
          A message was successfully received. TODO: Ref where MessageEvent is defined? | 
error
           | 
          Event
           | 
          TODO. | 
close
           | 
          Event
           | 
          
            The  object's underlying data
            transport has bee closed.
           | 
        
The following events fire on 
    objects:RTCPeerConnection
| Event name | Interface | Fired when... | 
|---|---|---|
connecting
           | 
          Event
           | 
          TODO | 
addstream
           | 
          
           | 
          A new stream has been added to the remote streams set. | 
removestream
           | 
          
           | 
          A stream has been removed from the remote streams set. | 
negotiationneeded
           | 
          Event
           | 
          The browser wishes to inform the application that session negotiation needs to be done at some point in the near future. | 
signalingstatechange
           | 
          Event
           | 
          
            The RTCPeerConnection
            signalingState has changed. This state change is the result of
            either setLocalDescription()
            or setRemoteDescription()
            being invoked.
           | 
        
iceconnectionstatechange
           | 
          Event
           | 
          
            The RTCPeerConnection
            ice connection state has changed.
           | 
        
icecandidate
           | 
          
           | 
          A new  is made available to
          the script. | 
        
datachannel
           | 
          
           | 
          A new  is dispatched to the
          script in response to the other peer creating a channel. | 
        
identityresult
           | 
          
           | 
          A new  is dispatched to the
          script when an identity assertion is successfully generated by an
          IdP. | 
        
peeridentity
           | 
          Event
           | 
          A new Event is dispatched to the script when
          an identity assertion provided by a peer is successfully
          validated. | 
        
idpassertionerror
           | 
          
           | 
          A new  is
          dispatched to the script when an IdP encounters an error while
          generating an identity assertion. | 
        
idpvalidationerror
           | 
          
           | 
          A new  is dispatched to the script
          when an IdP encounters an error while validating an identity
          assertion. | 
        
The following events fire on 
    objects:RTCDTMFSender
| Event name | Interface | Fired when... | 
|---|---|---|
tonechange
           | 
          Event
           | 
          The  object has either just
          begun playout of a tone (returned as the tone
          attribute) or just ended playout of a tone (returned as an empty
          value in the tone attribute). | 
        
TBD
This section will be removed before publication.
The editors wish to thank the Working Group chairs and Team Contact, Harald Alvestrand, Stefan Håkansson and Dominique Hazaël-Massieux, for their support. Substantial text in this specification was provided by many people including Martin Thomson, Harald Alvestrand, Justin Uberti, and Eric Rescorla.