Group call

This page explains the key functions of group call consisting of how to create a room and how a user can participate in a group call by entering and exiting a room from your app.

Note: Tutorial is also available on how to build a Kotlin video group chat app.

You can choose to create a room that supports up to 6 participants with video or a room that supports up to 100 participants with audio. When a user creates a room in your app, the room’s status becomes OPEN and a ROOM_ID is generated.

You can create a room through the Calls API as shown below by using the createRoom() method.

val params = RoomParams(RoomType.SMALL_ROOM_FOR_VIDEO)
SendBirdCall.createRoom(params, object : RoomHandler {
    override fun onResult(room: Room?, e: SendBirdException?) {
         if (room == null || e != null) {
              // Handle error.
              return
         }

         // room is created with a unique identifier room.roomId.
    }
})

You can retrieve a list of rooms by using the RoomListQuery and the following table shows all supported filters for the RoomListQuery to search for specific rooms you want to retrieve.

You can specify the above filters as shown below:

val aWeekAgo = Calendar.getInstance().apply {
    add(Calendar.DAY_OF_YEAR, -7)
}

val params = RoomListQuery.Params()
    .setType(RoomType.LARGE_ROOM_FOR_AUDIO_ONLY)
    .setLimit(50)
    .setState(RoomState.OPEN)
    .setRangeForCurrentParticipantCount(Range.greaterThanOrEqualTo(1))
    .setRangeForCreatedAt(
         Range.greaterThanOrEqualTo(aWeekAgo.timeInMillis)
    )

To retrieve a list of rooms, call the RoomListQuery.next(RoomListQueryResultHandler) method.

val query = SendBirdCall.createRoomListQuery(params)
query.next(object : RoomListQueryResultHandler {
    override fun onResult(rooms: List<Room>, e: SendBirdException?) {
         if (e != null) {
              // Error has occurred.
              return
         }
         ...
    }
})

When a list of rooms is retrieved, you can show the list to a user and allow the user to select a room they want to enter.

rooms[index].enter(EnterParams(), object : CompletionHandler {
    override fun onResult(e: SendBirdException?) {
          // User has entered the room
    }
})

Note: The room data returned from the query is not updated unless the user has entered the room. To update the details about a room, call the SendBirdCall.fetchRoomById() method.

A user can search a room with a specific room ID to participate in a group call at any time. When a user enters a room, a participant is created with a unique participant ID to represent the user in the room.

To enter a room, you must first acquire the room instance from Sendbird server with the room ID. To fetch the most up-to-date room instance from Sendbird server, use the SendBirdCall.fetchRoomById() method. Also, you can use the SendBirdCall.getCachedRoomById() method that returns the most recently cached room instance from Sendbird Calls SDK.

SendBirdCall.fetchRoomById(ROOM_ID, object : RoomHandler {
    override fun onResult(room: Room?, e: SendBirdException?) {
         if (room == null || e != null) {
              // Handle error.
              return
         }

         // room with the identifier ROOM_ID is fetched from the Sendbird server.
    }
})

val room = SendBirdCall.getCachedRoomById(ROOM_ID)
// Returns the most recently cached room with the identifier ROOM_ID from the SDK.
// If there is no such room with the given room ID, null is returned.

Note: A user can enter the room using multiple devices or browser tabs. Entering from each device or browser tab will create a new participant.

Once the room is retrieved, call the enter() method to enter the room.

room.enter(params, object : CompletionHandler {
    override fun onResult(e: SendBirdException?) {
        if (e != null) {
            // Handle error.
        }

        // User has successfully entered room.
    }
})

In a room, a single user can enter the same room multiple times as a different participant. However, if you want to prevent the user from entering the room simultaneously using different mobile devices and web browsers, you can kick out siblings of the user by calling room.enter(). It will result the user to be the unique participant remaining in the room.

val enterParams = EnterParams().setAudioEnabled(true).setVideoEnabled(true).setKickSiblings(true)
room.enter(enterParams, CompletionHandler { e ->
    if (e != null) {
        // Handle error.
        return@CompletionHandler
    }
    // User has successfully entered room and any other participants of the same user will be kicked out.
})

Note: Share the room ID with other users for them to enter the room from the client app.

To leave a room, call room.exit(). On the room handlers of the remaining participants, the RoomListener.onRemoteParticipantExited() method will be called.

room.exit()

If you would like to delete a room, you can call the delete() method. When this method is called successfully, the room will be permanently deleted, all participants in the room will be exited automatically, and the media connection will be stopped. Any participants in the room can delete the room.

room.delete { e ->
    if (e != null) {
        // An error occurred.
        return@delete
    }

}

A user can receive events of a room that they are currently participating. Users will be notified when other participants enter or leave the room, change their media settings or when the room is deleted.

Add event listener for the user to receive events that occur in a room that the user joins as a participant.

room.addListener(UNIQUE_ID, MyRoomListener())

class MyRoomListener : RoomListener {
}

When a participant joins or leaves the room, other participants in the room will receive the following events.

class MyRoomListener : RoomListener {
    ...
    // Called when a remote participant has entered a room.
    override fun onRemoteParticipantEntered(participant: RemoteParticipant) {}

    // Called when a remote participant has exited a room.
    override fun onRemoteParticipantExited(participant: RemoteParticipant) {}
    ...
}

A local participant can change the media settings such as muting their microphone or turning off their camera by using muteMicrophone() or stopVideo(). Other participants will receive events that notify them of the corresponding media setting changes.

class MyRoomListener : RoomListener {
    // Called when a remote participant's video settings have changed.
    override fun onRemoteVideoSettingsChanged(participant: RemoteParticipant) {}

    // Called when a remote participant's audio settings have changed.
    override fun onRemoteAudioSettingsChanged(participant: RemoteParticipant) {}
}

A local participant may lose their media stream in the room if their network connection is unstable. The onLocalParticipantDisconnected event listener will be sent to the local participant when they are disconnected. Once the media stream is reconnected, the onLocalParticipantReconnected event listener will be sent.

You can use these events to alert the local participants to switch to a more stable network or take other appropriate actions to stay connected to the room. Implement the code below to receive events on local participant's connection status.

class MyRoomListener : RoomListener {
    ...
    // Called when local participant's network is interrupted and the local participant is disconnected from the server.
    override fun onLocalParticipantDisconnected(participant: LocalParticipant) {}

    // Called when local participant's network connection is restored and the local participant is reconnected to the server.
    override fun onLocalParticipantReconnected(participant: LocalParticipant) {}
    ...
}

To delete a room through Calls Platform API, see Delete a room in the Calls API documentation. When a room is deleted, participants in the room will receive the following event.

class MyRoomListener : RoomListener {
   // Called when the room has been deleted.
   override fun onDeleted() {}
}

To stop receiving events about a room, remove the registered listeners as shown below:

// Removes a listener that have the matching identifier.
room.removeListener(UNIQUE_ID)

// Removes all listeners to stop receiving events about a room.
room.removeAllListeners()

You can let users into a room by sharing the room ID or by sending invitation to certain users as a notification. Invitees can accept or decline your invitations and you can also cancel them.

First, you need to be in the room to which you would like to invite other users. Follow the steps in Create a room and Enter the room to invite other users.

Send an invitation with the invitee's user ID and the room ID to the user you want to invite. When the invitation is sent successfully, the invited user will receive a notification on their device notifying them that you've invited them to join a room.

In order to send push notifications, you must configure the push notification certificates on Sendbird Dashboard and upload the device's push tokens after you authenticate. Refer to our notifications guide for more information.

room.sendInvitation(inviteeId) { roomInvitation, e ->
    if (e != null) {
        // An error occurred while sending an invitation.
        return@sendInvitation
    }
    // Successfully sent an invitation to the invitee.
}

When a user is invited, they will receive a notification that shows information about who invited them to which room. To show such information, you must pass the push notification to Sendbird Calls SDK as shown below.

class MyFirebaseMessagingService : FirebaseMessagingService() {
    override fun onMessageReceived(remoteMessage: RemoteMessage) {
        handleFirebaseMessageData(remoteMessage.data)
        ...
    }
    ...
}

When the push notification is passed to the Calls SDK, the onInvitationReceived handler will be called and the option will automatically be shown to the invitee to accept or decline the invitation.

SendBirdCall.addListener(UUID.randomUUID().toString(), object : SendBirdCallListener() {
    override fun onInvitationReceived(invitation: RoomInvitation) {
        ...
    }

    override fun onRinging(call: DirectCall) {
        ...
    }
})

When the notification pops on the invitee's device, a RoomInvitation class is created in the class that you added event handlers for the room. If you would like to provide information in the RoomInvitation class on other screens, you need to retrieve the class by using SendbirdCall.getRoomInvitation(roomInvitationId: String) as shown below.

val roomInvitation = SendBirdCall.getRoomInvitation(roomInvitationId);

If you would like to cancel an invitation that you sent, follow the code below. When you cancel the invitation, the invited user won't be able to enter the room when they open the notification.

roomInvitation.cancel { e ->
    if (e != null) {
        // An error occurred.
        return@cancel
    }
}

When the invited user accepts or declines the invitation, the user who invited them will be notified. You can add UI updates to let the inviter know whether the user they invited accepted or declined the invitation.

override fun onInvitationReceived(invitation: RoomInvitation) {
    // Accept an invitation.
    roomInvitation.accept { e ->
        // Invitation was accepted with e
    }

    // Decline an invitation.
    roomInvitation.decline { e ->
        // Invitation was accepted with e
    }
}

Call room.enter() to let the invitee enter the room once the invitee accepts the invitation. After the invitee enters and gets connected to the room, the inviter and invitee will be able to view each other's media stream.

With custom items for group calls, you can store additional information as key-value pairs to a room in the Room object. Custom key-value items are saved as a Map<String, String> and can be updated or deleted as long as the room status is OPEN. Information related to customer service, refund, or inquiry can be added as custom items for better user experience.

When a room is created, users can add custom items in RoomParams as a Map<String, String>. By default, the customItems is an empty Map object.

val customItems: Map<String, String> = mapOf("key" to "value")
val roomParams: RoomParams = RoomParams(ROOM_TYPE)
    .setCustomItems(customItems)
SendBirdCall.createRoom(roomParams, object : RoomHandler {
    override fun onResult(room: Room?, e: SendBirdException?) {

    }
})

Custom items can be updated or deleted as long as the room status is OPEN. If a new custom item has the same key as the existing custom item, the new item will update the value of the existing item. A new item with a new key will be added to the list of custom items. You can update existing custom items by calling the room.updateCustomItems(Map<String, String>, CustomItemsHandler).

You can delete custom items by calling the room.deleteCustomItems(Map<String, String>, CustomItemsHandler) with the list of keys that you want to delete from the existing custom items.

val customItems: Map<String, String> = mapOf("key" to "value")
room.updateCustomItems(items, object : CustomItemsHandler {
    override fun onResult(
        customItems: Map<String, String>?,
        affectedKeys: List<String>?,
        e: SendBirdException?
    ) {

    }
})

val keysToDelete: Set<String> = setOf("key1", "key2")
room.deleteCustomItems(keysToDelete, object : CustomItemsHandler {
    override fun onResult(
        customItems: Map<String, String>?,
        affectedKeys: List<String>?,
        e: SendBirdException?
    ) {

    }
})

A participant in a room can receive events from Sendbird server when other participants update or delete custom items in the room. Implement the RoomListener.onCustomItemsUpdated(List<String>) and the RoomListener.onCustomItemsDeleted(List<String>) from the RoomListener to receive events from other participants. Each event contains the list of keys of the changed custom items, such as updatedKeys or deletedKeys.

Custom items can be modified and the events are delivered to the RoomListener only when the room's status is OPEN and there are participants in the room. To check the custom items that had been changed for ended or ongoing calls in a room, you can use the Calls API or the room.fetchCustomItems(CustomItemsHandler?).

interface RoomListener {
    /**
    * An event for when the custom items are updated.
    *
    * @param updatedKeys Update keys.
    * @since 1.8.0
    */
    fun onCustomItemsUpdated(updatedKeys: List<String>)

    /**
    * An event for when the custom items are deleted.
    *
    * @param deletedKeys Delete keys.
    * @since 1.8.0
    */
    fun onCustomItemsDeleted(deletedKeys: List<String>
}

Participant’s actions, such as turning on or off their microphone or camera, in a room are handled by the participant objects.

To control the media of a local user, you can use the following methods from the Room.localParticipant object:

// Mutes the local participant's microphone.
room.localParticipant?.muteMicrophone()

// Unmutes the local participant's microphone.
room.localParticipant?.unmuteMicrophone()

// Stops the local participant's video.
room.localParticipant?.stopVideo()

// Starts the local participant's video.
room.localParticipant?.startVideo()

// Switches the local participant's front and back cameras.
room.localParticipant?.switchCamera(completionHandler)

When there is a participant in the room, a media stream is established between a participant and Sendbird server to support group calls.You can configure the user interface for participants in a room by using the properties in Participant.

The following is the process of how participants can send and receive media streams in a room:

Step 1: To send a media stream, a participant who would like to send its media stream has to be connected to Sendbird server.

Step 2: To receive a media stream, a participant who would like to receive a media stream from another participant has to be connected to the media server. Once connected, onRemoteParticipantStreamStarted() will be invoked which notifies that the receiving media stream has started.

Step 3: Add a view to show the received media stream.

To receive a video stream from a local participant, configure videoView property as shown below:

room.enter(params, object : CompletionHandler {
    override fun onResult(e: SendBirdException?) {
        if (e != null) {
            // Handle error.
        }

        // User has successfully entered room.
        val localParticipantVideoView: SendBirdVideoView = findViewById(R.id.local_participant_video_view)
        room.localParticipant?.videoView = localParticipantVideoView

    }
})

To receive a video stream from a remote participant, configure the videoView property as shown below:

room.addListener(UNIQUE_ID, object : RoomListener {
    ...
    override fun onRemoteParticipantEntered(participant: RemoteParticipant) {
        val remoteParticipantVideoView: SendBirdVideoView = findViewById(R.id.remote_participant_video_view)
        participant.videoView = remoteParticipant
    }
    ...
})

You can show participants in gallery view as they enter or exit the room by using RecyclerView and GridLayoutManager which dynamically change views. You can set the number of items to be the count of room.participants and the custom ViewHolder to represent each participant.

When the below methods in RoomListener are called, information for room.participants gets updated and the number of items are changed accordingly. To have the custom ViewHolder added or removed, you need to call adapter.notifyDataSetChanged() for the methods.

If a participant is not connected to the call or has turned off their video, you can set a default image to show on the screen for that participant. Otherwise, it will be shown as black to other participants. To check whether a participant has turned on their video or is connected to the room for a video call, refer to the isVideoEnabled and the state properties of a Participant object.

It is recommended to show an image such as the user’s profile image as the default image when the onRemoteParticipantEntered() method is invoked.

When the onRemoteParticipantStreamStarted() method is invoked, create a new SendBirdVideoView and set it to the participant by using participant.videoView and remove the default image.

When a participant loses media stream in a room due to connection issues, Sendbird Calls SDK automatically tries to reconnect the participant’s media streaming in the room. If the Calls SDK fails to reconnect for about 40 seconds, an error will be returned.

class MyRoomListener : RoomListener {
// Called when an error has occurred.
    override fun onError(e: SendBirdException, participant: Participant?) {
        if (e.code == SendBirdError.ERR_LOCAL_PARTICIPANT_LOST_CONNECTION) {
                // Handle reconnection failure here.
                // Clear resources for group calls.
          }
     }
}

Note: See the Error codes page for more information.

Cloud recording is a feature that allows you to record participants' audio and video in rooms and download the recorded files from Sendbird Dashboard. When the feature is turned on in a Sendbird application, audio of LARGE_ROOM_FOR_AUDIO_ONLY and audio and video of SMALL_ROOM_FOR_VIDEO are recorded.

To use the cloud recording feature, contact our support team. You can go to Settings > Calls > General on the dashboard to see if the feature is available for your Sendbird application.

To view the image in full screen, click on the

Recording starts in Open rooms when there are more than two participants in the room, and ends when there are no participants. Recorded files will be numbered in the file name and listed in the order of creation.

Once the file has been uploaded successfully, you can download it from the dashboard. To download the file, click the room of the recording you would like to download on Group calls. You can download the file immediately or later by using the link, which stays valid for 24 hours and can be reissued.

To view the image in full screen, click on the

Audio recordings from LARGE_ROOM_FOR_AUDIO_ONLY are processed to .aac files and audio and video recordings from SMALL_ROOM_FOR_VIDEO are processed to .mp4 files in default resolution of 1280 x 720. Each file can be downloaded for two weeks from the date the recorded file's upload has completed.