View Source WebRTC Media Events

This document described all messages exchanged between the WebRTC Endpoint and a client. In general, each media event has to be sent in the form:

{
  type: name,
  data: data
}

where the name of the event is the value of the type field, while data should carry the data shown below for every media event

table-of-contents
Table of contents

Below you can find a summary of all media events defined inside membrane_rtc_engine

generic-webrtc-endpoint-messages
Generic WebRTC Endpoint messages

Messages used by any WebRTC Endpoint plugin

WebRTC Endpoint receives these types of `media_events` from client:

Name	Description
join	sent when peer join WebRTC Endpoint
leave	sent when peer leaves WebRTC Endpoint
updatePeerMetadata	contains new metadata of a peer
updateTrackMetadata	contains new metadata of a track
custom	message forwarded to the endpoint associated with the peer

WebRTC Endpoint sends these types of messages to the client:

Name	Description
tracksPriority	contains all tracks that will be forwarded to peer until next `tracks_priority` message
peerDenied	sent if peer was rejected by server when joining to server
peerUpdated	contains new metadata of a peer
trackUpdated	contains new metadata of a track
tracksAdded	sent when some tracks were added by some peer
tracksRemoved	sent when some tracks were removed by some peer
peerJoined	sent after a new peer has joined the WebRTC Endpoint
peerAccepted	sent to a peer after he joins the WebRTC Endpoint
peerLeft	sent when some peer lefts the WebRTC Endpoint
peerRemoved	sent when peer is forcibly removed by the server
error	Notifies about an error that occurred
custom	custom message forwarded from endpoint to client

webrtc-custom-media-events
WebRTC custom media events

WebRTC endpoint receives these types of custom `media_event`s from client:

Name	Description
renegotiateTracks	A request from a peer to renegotiate tracks
prioritizeTrack	A request to prioritize the track
unprioritizeTrack	A request to unprioritize the track
preferedVideoSizes	informs of how many videos in different quality a peer wants to receive
candidate	Contains client's ICE candidate
sdpOffer	Contains an SDP offer from a client
setTargetTrackVariant	A request from a peer to receive a specific track variant

WebRTC endpoint sends these type of custom messages to client

Name	Description
offerData	Sends data needed by the client to create an offer
candidate	Contains an ICE candidate
sdpAnswer	Provides an SDP Answer to the client's offer
encodingSwitched	An information that a track will be sent with a specific encoding
vadNotification	An update on Voice Activity Detection

client-webrtc-endpoint
Client -> WebRTC Endpoint

join
`join`

Sent when peer want to join WebRTC Endpoint. It contains only peer's metadata
```
{
  "metadata": any
}
```

leave
`leave`

Sent when peer leaves WebRTC Endpoint. It contains no data
```
{}
```

updatepeermetadata
`updatePeerMetadata`

Contains new metadata of some peer
```
{
  "metadata": any
}
```

updatetrackmetadata
`updateTrackMetadata`

Contains new metadata of some track and an id of this track
```
{
  "trackId": track_id,
  "trackMetadata": any
}
```

custom
`custom`

A black-box for a message that WebRTC Endpoint will forward to the endpoint associated with the peer who sent the message.
```
any
```

webrtc-endpoint-client
WebRTC Endpoint -> Client

trackspriority
`tracksPriority`

Contains all tracks that will be forwarded to peer until the next tracks_priority message. This type of messages is sent only if DisplayManager is spawned
```
{
  tracks: tracks
}
```

peerdenied
`peerDenied`

Sent if peer was rejected by server when joining to server. It may contain a reason for rejection.
```
{
  data: text
}
```

peerupdated
`peerUpdated`

Contains information about updated metadata of one of the peers
```
{
  peerId: peer_id,
  metadata: any
}
```

trackupdated
`trackUpdated`

Contains information about new metadata of one of tracks

{
  peerId: peer_id,
  trackId: track_id,
  metadata: any
}

tracksadded
`tracksAdded`

Informs that one of the peers has added one or more tracks. It contains an id of that peer and a map of all tracks with track_ids as keys and track_metadata as value.
```
{
  peerId: peer_id,
  trackIdToMetadata: {
    track_id: any
  }
}
```

tracksremoved
`tracksRemoved`

Contains a list of tracks which have been removed by some peer and id of that peer
```
{
  peerId: peer_id,
  trackIds: track_ids
}
```

peerjoined
`peerJoined`

Message sent to all peers in the room after a new peer has joined WebRTC Endpoint. It contains id and metadata of the new peer.
```
{
  peer: {
    id: peer.id,
    metadata: peer.metadata
  }
}
```

peeraccepted
`peerAccepted`

Message sent to the peer after he's joined the WebRTC Endpoint. It contains his id and a list of information about peers in the Engine (id, metadata and a trackIdToMetadata like seen in tracksAdded)
```
{
  id: peer_id,
  peersInRoom: peers
}
```

peerleft
`peerLeft`

Sent to all remaining peers in the room after some peer has left. It contains an id of the peer who left.
```
{
  peerId: peer_id
}
```

peerremoved
`peerRemoved`

Sent to the peer that has been forcibly removed by the server
```
{
  peerId: peer_id,
  reason: any
}
```

error
`error`

Informs that an error occurred on the server providing a message to show
```
{
  message: any()
}
```

custom-1
`custom`

WARNING!! This type of media event is deprecated - will soon be removed.
A black-box for a message that the WebRTC Endpoint will forward to the client.
```
any
```

client-webrtc-enpoint
Client -> WebRTC Enpoint

renegotiatetracks
`renegotiateTracks`

Informs that a peer wants to renegotiate connection due to adding a track or removing a track
```
{}
```

prioritizetrack
`prioritizeTrack`

Contains an id of the track that the peer wants to prioritize
```
{
  trackId: trackId
}
```

unprioritizetrack
`unprioritizeTrack`

Contains an id of the track that the peer want to unprioritize.
```
{
  trackId: trackId
}
```

preferedvideosizes
`preferedVideoSizes`

Contains information of how many videos in different quality (high, medium, small) the peer would like to receive. allSameSize flag which indicates that all videos should be in the same quality.
```
{
  bigScreens: Int,
  mediumScreens: Int,
  smallScreens: Int,
  allSameSize: boolean
}
```

candidate
`candidate`

Contains an ICE candidate that is forwarded to the WebRTC Endpoint
```
{
  candidate: candidate,
  sdpMLineIndex: Int
}
```

sdpoffer
`sdpOffer`

Contains an SDP offer, a mapping between track_id and track_metadata, and a mapping between mid and track_id. Both maps contain only information about current peer sendonly tracks.
```
{
  sdpOffer: {
    type: "offer",
    sdp: sdp_offer
  },
  trackIdToTrackMetadata: {
    trackId: any
  }
  midToTrackId: mid_to_track_id
}
```

settargettrackvariant
`setTargetTrackVariant`

Informs that a peer wants to receive a specific track variant. The track variant will be sent whenever it is available. If choosen variant is unavailable, some other variant will be sent until choosen variant becomes active again.
```
{
  trackId => track_id,
  variant => variant
}
```

webrtc-enpoint-client
WebRTC Enpoint -> Client

offerdata
`offerData`

Contains information about the number of audio and video tracks that will be sent from the engine to the peer and information regarding the integrated TURN server.

{
  tracksTypes: {
    audio: Int,
    video: Int
  },
  integratedTurnServers: [{
    serverAddr: addr,
    serverPort: Int,
    transport: string,
    password: string,
    username: string
  }]
}

candidate-1
`candidate`

Contains information about an ICE candidate which will be sent to the client

{
  candidate: candidate,
  sdpMLineIndex: sdp_m_line_index,
  sdpMid: nil,
  usernameFragment: nil
}

sdpanswer
`sdpAnswer`

Contains an SDP answer and mapping between mid and track_id for all tracks (active, inactive, inbound and outbound)
```
{
  type: "answer",
  sdp: sdp_answer,
  midToTrackId: mid_to_track_id
}
```

encodingswitched
`encodingSwitched`

Informs that track with id trackId belonging to peer with id peerId will be sent in encoding encoding now. The meaning is as follows:
"low_bandwidth" - we no longer have enough bandwidth to maintain current track quality
"encoding_inactive" - encoding became inactive

"other" - it was hard to determine exact reason of encoding switch

{
  peerId: peer_id,
  trackId: track_id,
  encoding: encoding,
  reason: "low_bandwidth" | "encoding_inactive" | "other"
}

vadnotification
`vadNotification`

Informs that the track denoted by trackId has changed their voice actiivty
For this notification to work, the server must be configured to use VAD extension and the sender must support it.

{
  trackId: track_id,
  status: "silence" | "speech"
}

bandwidthestimation
`bandwidthEstimation`

Informs about client's available incoming bitrate (a.k.a. download) estimated by the server. It is measured in bits per second.
For this notification to work, the server must be configured to use TWCC extension and the sender must support it.

{
  estimation: estimation,
}

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table-of-contents Table of contents

generic-webrtc-endpoint-messages Generic WebRTC Endpoint messages

WebRTC Endpoint receives these types of media_events from client:

WebRTC Endpoint sends these types of messages to the client:

webrtc-custom-media-events WebRTC custom media events

WebRTC endpoint receives these types of custom media_events from client:

WebRTC endpoint sends these type of custom messages to client

client-webrtc-endpoint Client -> WebRTC Endpoint

join join

leave leave

updatepeermetadata updatePeerMetadata

updatetrackmetadata updateTrackMetadata

custom custom

webrtc-endpoint-client WebRTC Endpoint -> Client

trackspriority tracksPriority

peerdenied peerDenied

peerupdated peerUpdated

trackupdated trackUpdated

tracksadded tracksAdded

tracksremoved tracksRemoved

peerjoined peerJoined

peeraccepted peerAccepted

peerleft peerLeft

peerremoved peerRemoved

error error

custom-1 custom

client-webrtc-enpoint Client -> WebRTC Enpoint

renegotiatetracks renegotiateTracks

prioritizetrack prioritizeTrack

unprioritizetrack unprioritizeTrack

preferedvideosizes preferedVideoSizes

candidate candidate

sdpoffer sdpOffer

settargettrackvariant setTargetTrackVariant

webrtc-enpoint-client WebRTC Enpoint -> Client

offerdata offerData

candidate-1 candidate

sdpanswer sdpAnswer

encodingswitched encodingSwitched

vadnotification vadNotification

bandwidthestimation bandwidthEstimation