Skip to main content
Version: 5.5

Group call flow

This page describes the flow of LINE Planet's group call (conference).

In the diagrams below, app clients and the app server belong to the application domain, and PlanetKit and LINE Planet Cloud belong to the LINE Planet domain.

Joining a group call​

To join a group call, an app client must call joinConference(). When a user joins a group call, the evtConnected event occurs.

Note

A room ID is required to join a group call room. Therefore, app clients must share a room ID through an application communication channel before joining a group call.

The following diagram shows a flow for joining a group call, where Client 01 joins a group video call with video and then Client K joins the group call without video.

Group call join sequence diagram
  1. When Client 01 wants to join a call, the app client of Client 01 calls joinConference().
  2. Planet Cloud invokes the Group Call Event callback to notify the app server of the new group call.
  3. The evtConnected event occurs on the app client of Client 01.
  4. When Client K wants to join the call, the app client of Client K calls joinConference().
  5. Planet Cloud invokes the Group Call Event callback to notify the app server of the group call's status change.
  6. On the app client of Client 01, the evtPeerListUpdated event occurs. On the app client of Client K, the evtConnected, evtPeerListUpdated, and evtPeersVideoUpdated events occur.

In the flow above, you can see three related events.

EventConditionDescription
evtConnectedAfter joinConference() is calledCompletion callback
evtPeerListUpdatedAfter someone joins or leaves the roomDelivers the list of participants who newly joined or left the room
evtPeersVideoUpdated- After someone joins the room and enables or disables video
- When someone joins the room with video enabled		Delivers the list of participants who enabled or disabled video

Peer list updated event​

The evtPeerListUpdated event occurs whenever the list of participants is updated. Therefore, after Client K joins a room, both Client 01 and Client K receive this event.

Peers video updated event​

The evtPeersVideoUpdated event occurs whenever a participant's video stream changes.

In the example above, only Client 01 is sending video, and the evtPeersVideoUpdated event lets Client K know that Client 01 enabled video.

Tip

The evtPeersVideoUpdated event can also be generated by enabling a video call during an audio call. For more information, refer to Enable video call from audio call.

Update interval of the events​

An app client receives evtPeerListUpdated and evtPeersVideoUpdated based on the latest information within the update interval. As a result, the app client may not receive events for quick changes that occur within an update interval, such as when someone joins and leaves the room right away.

LINE Planet Cloud has a scheduler that updates information internally, and the scheduling interval becomes longer as the number of participants increases. Therefore, keep in mind that the update becomes slower in proportion to the number of participants.

Requesting peer video​

An app client automatically receives the audio stream after receiving the evtConnected event. However, a video stream is not sent automatically by LINE Planet Cloud unless the app client calls requestPeerVideo() with a proper video resolution.

Applications can find out who enabled the video stream from the evtPeersVideoUpdated callback.

Group call request peer video sequence diagram

It is recommended that you pass an appropriate resolution value when calling requestPeerVideo(). For a more detailed explanation, see Peer video resolution in a group call.

Leaving a group call​

To leave a group call, an app client must call leaveConference(). On the app client of the user who left the group call, the evtDisconnected event occurs. On the app clients of peers, the evtPeerListUpdated event occurs because the list of participants has been changed.

Participant with video enabled​

If the participant who enabled video leaves the room, evtPeersVideoUpdated is sent to other participants.

Group call leave video enabled sequence diagram
  1. When Client 01 wants to leave a call, the app client of Client 01 calls leaveConference().
  2. On the app client of Client K, the evtPeersVideoUpdated and evtPeerListUpdated events occur. On the app client of Client 01, the evtDisconnected event occurs.
  3. Planet Cloud invokes the Group Call Event callback to notify the app server of the group call's status change.
Note

The evtPeersVideoUpdated with DISABLED state is sent only to participants who are using WebPlanetKit 5.0 or higher.

Participant with video disabled​

If the participant who disabled video leaves the room, evtPeersVideoUpdated does not occur.

Group call leave video disabled sequence diagram
  1. When Client K wants to leave a call, the app client of Client K calls leaveConference().
  2. On the app client of Client 01, the evtPeerListUpdated event occurs. On the app client of Client K, the evtDisconnected event occurs.
  3. Planet Cloud invokes the Group Call Event callback to notify the app server of the group call's status change.

APIs related to group calls are as follows.

Client API​

Methods​

Events​

Server API​