@twilio/webrtc
v4.6.0
Published
WebRTC-related APIs and shims used by twilio-video.js
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twilio-webrtc.js
twilio-webrtc.js contains the various WebRTC shims used by twilio-video.js. It is not intended for general consumption.
Installation
npm install --save @twilio/webrtc
Exports
The following WebRTC API shims are available:
const {
getStats,
getUserMedia,
MediaStream,
MediaStreamTrack,
RTCIceCandidate,
RTCPeerConnection,
RTCSessionDescription
} = require('@twilio/webrtc');
getStats
getStats
resolves with normalized WebRTC statistics for the active ICE
candidate pair and each MediaStreamTrack
, local or remote, of a particular
RTCPeerConnection
.
/**
* Get the statistics for a given RTCPeerConnection.
* @param {RTCPeerConnection} peerConnection
* @returns {Promise<StandardizedStatsResponse>}
*/
function getStats(peerConnection) {}
NOTE: StandardizedStatsResponse
normalizes the different formats of the stats returned by RTCPeerConnection#getStats
in different
browsers. It does not conform to the W3C spec.
getUserMedia
getUserMedia
accepts a MediaStreamConstraints
object and resolves
with a MediaStream
. By default, it requests both audio and video.
/**
* Request media from the user.
* @param {MediaStreamConstraints} [constraints={audio: true, video: true}]
* @returns {Promise<MediaStream>}
*/
function getUserMedia(constraints) {}
RTCPeerConnection
RTCPeerConnection
abstracts away some of the browser-specific implementations
of WebRTC, and implements some WebRTC features that are not present in some
browsers.
Chrome
- Adds rollback support, according to the workaround specified here.
- Adds "track" event support, as per the workaround in webrtc-adapter.
- Provides a workaround for the case where, when the SSRC of a
MediaStreamTrack
changes, the browser treats this as a removal of the existingMediaStreamTrack
and the addition of a newMediaStreamTrack
. - Adds support for getting and setting
maxPacketLifeTime
on RTCDataChannels by remapping the legacy propertymaxRetransmitTime
tomaxPacketLifeTime
. See this bug for more information. - Provides a workaround for this bug, where calling
removeTrack
with anRTCRtpSender
that is not created by theRTCPeerConnection
in question throws an exception.
Firefox
- For new offers, adds support for calling
setLocalDescription
andsetRemoteDescription
inhave-local-offer
andhave-remote-offer
signaling states respectively. - Adds support for calling
createOffer
in signaling statehave-local-offer
. - The above features are implemented using rollback to work around this bug.
- Provides a workaround for this bug, where the browser may change the previously negotiated DTLS role in an answer, which breaks Chrome.
- Provides a workaround for this bug,
where the browser throws when
RTCPeerConnection.prototype.peerIdentity
is accessed. - Works around Firefox Bug 1480277.
Safari
- Adds rollback support, according to the workaround specified here.
- Provides a workaround for the case where, when the SSRC of a
MediaStreamTrack
changes, the browser treats this as a removal of the existingMediaStreamTrack
and the addition of a newMediaStreamTrack
. - Provides a workaround for this bug, where webrtc-adapter's shimmed
addTrack
method does not return theRTCRtpSender
associated with the added track.
RTCSessionDescription
RTCSessionDescription
abstracts away some of the browser-specific implementations
of WebRTC for Firefox and Safari, and works around this bug
in Chrome, where the native RTCSessionDescription
constructor throws when its argument is
{ type: 'rollback'}
.
Others
MediaStream
, MediaStreamTrack
, and RTCIceCandidate
abstracts away their
browser-prefixed counterparts for earlier browser versions.