Enable group calls without video and audio track by configuration of MatrixClient

spec/unit/webrtc/groupCall.spec.ts

@@ -109,7 +109,7 @@ const mockGetStateEvents = (type: EventType, userId?: string): MatrixEvent[] | M
 const ONE_HOUR = 1000 * 60 * 60;
 
 const createAndEnterGroupCall = async (cli: MatrixClient, room: Room): Promise<GroupCall> => {
- const groupCall = new GroupCall(cli, room, GroupCallType.Video, false, GroupCallIntent.Prompt, FAKE_CONF_ID);
+ const groupCall = new GroupCall(cli, room, GroupCallType.Video, false, GroupCallIntent.Prompt, false, FAKE_CONF_ID);
 
  await groupCall.create();
  await groupCall.enter();
@@ -135,7 +135,7 @@ describe("Group Call", function () {
  mockClient = typedMockClient as unknown as MatrixClient;
 
  room = new Room(FAKE_ROOM_ID, mockClient, FAKE_USER_ID_1);
- groupCall = new GroupCall(mockClient, room, GroupCallType.Video, false, GroupCallIntent.Prompt);
+ groupCall = new GroupCall(mockClient, room, GroupCallType.Video, false, GroupCallIntent.Prompt, false);
  room.currentState.members[FAKE_USER_ID_1] = {
  userId: FAKE_USER_ID_1,
  membership: "join",
@@ -484,7 +484,7 @@ describe("Group Call", function () {
  describe("PTT calls", () => {
  beforeEach(async () => {
  // replace groupcall with a PTT one
- groupCall = new GroupCall(mockClient, room, GroupCallType.Video, true, GroupCallIntent.Prompt);
+ groupCall = new GroupCall(mockClient, room, GroupCallType.Video, true, GroupCallIntent.Prompt, false);
 
  await groupCall.create();
 
@@ -647,6 +647,7 @@ describe("Group Call", function () {
  GroupCallType.Video,
  false,
  GroupCallIntent.Prompt,
+ false,
  FAKE_CONF_ID,
  );
 
@@ -656,6 +657,7 @@ describe("Group Call", function () {
  GroupCallType.Video,
  false,
  GroupCallIntent.Prompt,
+ false,
  FAKE_CONF_ID,
  );
  });
@@ -1465,6 +1467,7 @@ describe("Group Call", function () {
  GroupCallType.Video,
  false,
  GroupCallIntent.Prompt,
+ false,
  FAKE_CONF_ID,
  );
  await groupCall.create();

src/client.ts

@@ -371,6 +371,13 @@ export interface ICreateClientOpts {
  * Defaults to a built-in English handler with basic pluralisation.
  */
  roomNameGenerator?: (roomId: string, state: RoomNameState) => string | null;
+
+ /**
+ * If true, participant can join group call without video and audio this has to be allowed. By default, a local
+ * media stream is needed to establish a group call.
+ * Default: false.
+ */
+ isVoipWithNoMediaAllowed?: boolean;
 }
 
 export interface IMatrixClientCreateOpts extends ICreateClientOpts {
@@ -1169,6 +1176,7 @@ export class MatrixClient extends TypedEventEmitter<EmittedEvents, ClientEventHa
  public iceCandidatePoolSize = 0; // XXX: Intended private, used in code.
  public idBaseUrl?: string;
  public baseUrl: string;
+ public readonly isVoipWithNoMediaAllowed;
 
  // Note: these are all `protected` to let downstream consumers make mistakes if they want to.
  // We don't technically support this usage, but have reasons to do this.
@@ -1313,6 +1321,7 @@ export class MatrixClient extends TypedEventEmitter<EmittedEvents, ClientEventHa
  this.iceCandidatePoolSize = opts.iceCandidatePoolSize === undefined ? 0 : opts.iceCandidatePoolSize;
  this.supportsCallTransfer = opts.supportsCallTransfer || false;
  this.fallbackICEServerAllowed = opts.fallbackICEServerAllowed || false;
+ this.isVoipWithNoMediaAllowed = opts.isVoipWithNoMediaAllowed || false;
 
  if (opts.useE2eForGroupCall !== undefined) this.useE2eForGroupCall = opts.useE2eForGroupCall;
 
@@ -1880,14 +1889,17 @@ export class MatrixClient extends TypedEventEmitter<EmittedEvents, ClientEventHa
  throw new Error(`Cannot find room ${roomId}`);
  }
 
+ // Because without Media section a WebRTC connection is not possible, so need a RTCDataChannel to set up a
+ // no media WebRTC connection anyway.
  return new GroupCall(
  this,
  room,
  type,
  isPtt,
  intent,
+ this.isVoipWithNoMediaAllowed,
  undefined,
- dataChannelsEnabled,
+ dataChannelsEnabled || this.isVoipWithNoMediaAllowed,
  dataChannelOptions,
  ).create();
  }

src/webrtc/call.ts

@@ -390,6 +390,9 @@ export class MatrixCall extends TypedEventEmitter<CallEvent, CallEventHandlerMap
  // Used to keep the timer for the delay before actually stopping our
  // video track after muting (see setLocalVideoMuted)
  private stopVideoTrackTimer?: ReturnType<typeof setTimeout>;
+ // Used to allow connection without Video and Audio. To establish a webrtc connection without media a Data channel is
+ // needed At the moment this property is true if we allow MatrixClient with isVoipWithNoMediaAllowed = true
+ private readonly isOnlyDataChannelAllowed: boolean;
 
  /**
  * Construct a new Matrix Call.
@@ -420,6 +423,8 @@ export class MatrixCall extends TypedEventEmitter<CallEvent, CallEventHandlerMap
  utils.checkObjectHasKeys(server, ["urls"]);
  }
  this.callId = genCallID();
+ // If the Client provides calls without audio and video we need a datachannel for a webrtc connection
+ this.isOnlyDataChannelAllowed = this.client.isVoipWithNoMediaAllowed;
  }
 
  /**
@@ -944,7 +949,11 @@ export class MatrixCall extends TypedEventEmitter<CallEvent, CallEventHandlerMap
  // According to previous comments in this file, firefox at some point did not
  // add streams until media started arriving on them. Testing latest firefox
  // (81 at time of writing), this is no longer a problem, so let's do it the correct way.
- if (!remoteStream || remoteStream.getTracks().length === 0) {
+ //
+ // For example in case of no media webrtc connections like screen share only call we have to allow webrtc
+ // connections without remote media. In this case we always use a data channel. At the moment we allow as well
+ // only data channel as media in the WebRTC connection with this setup here.
+ if (!this.isOnlyDataChannelAllowed && (!remoteStream || remoteStream.getTracks().length === 0)) {
  logger.error(
  `Call ${this.callId} initWithInvite() no remote stream or no tracks after setting remote description!`,
  );

src/webrtc/groupCall.ts

@@ -216,6 +216,7 @@ export class GroupCall extends TypedEventEmitter<
  public type: GroupCallType,
  public isPtt: boolean,
  public intent: GroupCallIntent,
+ public readonly initCallWithoutVideoAndAudio: boolean,
  groupCallId?: string,
  private dataChannelsEnabled?: boolean,
  private dataChannelOptions?: IGroupCallDataChannelOptions,
@@ -374,8 +375,15 @@ export class GroupCall extends TypedEventEmitter<
  try {
  stream = await this.client.getMediaHandler().getUserMediaStream(true, this.type === GroupCallType.Video);
  } catch (error) {
- this.state = GroupCallState.LocalCallFeedUninitialized;
- throw error;
+ // If is allowed to join a call without a media stream, then we
+ // don't throw an error here. But we need an empty Local Feed to establish
+ // a connection later.
+ if (this.initCallWithoutVideoAndAudio) {
+ stream = new MediaStream();
+ } else {
+ this.state = GroupCallState.LocalCallFeedUninitialized;
+ throw error;
+ }
  }
 
  // The call could've been disposed while we were waiting, and could
@@ -609,6 +617,11 @@ export class GroupCall extends TypedEventEmitter<
  * @returns Whether muting/unmuting was successful
  */
  public async setLocalVideoMuted(muted: boolean): Promise<boolean> {
+ // Because we need a Local Call Feed to establish a call connection, we avoid muting video in case of empty
+ // video track. In this way we go sure if a client implements muting we don't raise an error.
+ if (this.initCallWithoutVideoAndAudio && this.localCallFeed?.stream.getVideoTracks().length === 0) {
+ return false;
+ }
  // hasAudioDevice can block indefinitely if the window has lost focus,
  // and it doesn't make much sense to keep a device from being muted, so
  // we always allow muted = true changes to go through

src/webrtc/groupCallEventHandler.ts

@@ -183,8 +183,11 @@ export class GroupCallEventHandler {
  callType,
  isPtt,
  callIntent,
+ this.client.isVoipWithNoMediaAllowed,
  groupCallId,
- content?.dataChannelsEnabled,
+ // Because without Media section a WebRTC connection is not possible, so need a RTCDataChannel to set up a
+ // no media WebRTC connection anyway.
+ content?.dataChannelsEnabled || this.client.isVoipWithNoMediaAllowed,
  dataChannelOptions,
  );