feat(multi-stream-support) Add screenshare as a second video track to the call.

* feat(multi-stream-support) Add screenshare as a second video track to the call.
This feature is behind a sendMultipleVideoStreams config.js flag. sourceNameSignaling flag also needs to enabled. Sending multiple tracks is currently supported only on endpoints running in unified plan mode. However, clients with source-name signaling enabled and running in plan-b can still receive multiple streams .

* squash: check if there is an existing track before adding camera/desktop

* squash: enable multi-stream only on unified plan endpoints.

conference.js

@@ -52,7 +52,7 @@ import {
     sendLocalParticipant,
     nonParticipantMessageReceived
 } from './react/features/base/conference';
-import { getReplaceParticipant } from './react/features/base/config/functions';
+import { getReplaceParticipant, getMultipleVideoSupportFeatureFlag } from './react/features/base/config/functions';
 import {
     checkAndNotifyForNewDevice,
     getAvailableDevices,
@@ -106,6 +106,7 @@ import {
     updateSettings
 } from './react/features/base/settings';
 import {
+    addLocalTrack,
     createLocalPresenterTrack,
     createLocalTracksF,
     destroyLocalTracks,
@@ -1444,11 +1445,13 @@ export default {
      * @returns {Promise}
      */
     useVideoStream(newTrack) {
+        const state = APP.store.getState();
+
         logger.debug(`useVideoStream: ${newTrack}`);
 
         return new Promise((resolve, reject) => {
             _replaceLocalVideoTrackQueue.enqueue(onFinish => {
-                const oldTrack = getLocalJitsiVideoTrack(APP.store.getState());
+                const oldTrack = getLocalJitsiVideoTrack(state);
 
                 logger.debug(`useVideoStream: Replacing ${oldTrack} with ${newTrack}`);
 
@@ -1459,6 +1462,26 @@ export default {
                     return;
                 }
 
+                // In the multi-stream mode, add the track to the conference if there is no existing track, replace it
+                // otherwise.
+                if (getMultipleVideoSupportFeatureFlag(state)) {
+                    const trackAction = oldTrack
+                        ? replaceLocalTrack(oldTrack, newTrack, room)
+                        : addLocalTrack(newTrack);
+
+                    APP.store.dispatch(trackAction)
+                        .then(() => {
+                            this.setVideoMuteStatus();
+                        })
+                        .then(resolve)
+                        .catch(error => {
+                            logger.error(`useVideoStream failed: ${error}`);
+                            reject(error);
+                        })
+                        .then(onFinish);
+
+                    return;
+                }
                 APP.store.dispatch(
                     replaceLocalTrack(oldTrack, newTrack, room))
                     .then(() => {

react/features/av-moderation/constants.js

@@ -26,6 +26,7 @@ export const CS_MODERATION_NOTIFICATION_ID = 'screensharing-moderation';
 
 export const MODERATION_NOTIFICATIONS = {
     [MEDIA_TYPE.AUDIO]: AUDIO_MODERATION_NOTIFICATION_ID,
+    [MEDIA_TYPE.SCREENSHARE]: CS_MODERATION_NOTIFICATION_ID,
     [MEDIA_TYPE.VIDEO]: VIDEO_MODERATION_NOTIFICATION_ID,
     [MEDIA_TYPE.PRESENTER]: CS_MODERATION_NOTIFICATION_ID
 };

react/features/base/conference/middleware.web.js

@@ -1,13 +1,30 @@
 // @flow
 
+import { AUDIO_ONLY_SCREEN_SHARE_NO_TRACK } from '../../../../modules/UI/UIErrors';
+import { showNotification, NOTIFICATION_TIMEOUT_TYPE } from '../../notifications';
 import { setSkipPrejoinOnReload } from '../../prejoin';
-import { JitsiConferenceErrors } from '../lib-jitsi-meet';
+import { setScreenAudioShareState, setScreenshareAudioTrack } from '../../screen-share';
+import { AudioMixerEffect } from '../../stream-effects/audio-mixer/AudioMixerEffect';
+import { setAudioOnly } from '../audio-only';
+import { getMultipleVideoSupportFeatureFlag } from '../config/functions.any';
+import { JitsiConferenceErrors, JitsiTrackErrors } from '../lib-jitsi-meet';
+import { MEDIA_TYPE, setScreenshareMuted, VIDEO_TYPE } from '../media';
 import { MiddlewareRegistry } from '../redux';
+import {
+    addLocalTrack,
+    createLocalTracksF,
+    getLocalDesktopTrack,
+    getLocalJitsiAudioTrack,
+    replaceLocalTrack,
+    TOGGLE_SCREENSHARING
+} from '../tracks';
 
 import { CONFERENCE_FAILED, CONFERENCE_JOINED } from './actionTypes';
+import { getCurrentConference } from './functions';
 import './middleware.any';
 
-MiddlewareRegistry.register(({ dispatch, getState }) => next => action => {
+MiddlewareRegistry.register(store => next => action => {
+    const { dispatch, getState } = store;
     const { enableForcedReload } = getState()['features/base/config'];
 
     switch (action.type) {
@@ -25,7 +42,153 @@ MiddlewareRegistry.register(({ dispatch, getState }) => next => action => {
 
         break;
     }
+    case TOGGLE_SCREENSHARING: {
+        getMultipleVideoSupportFeatureFlag(getState()) && _toggleScreenSharing(action, store);
+
+        break;
+    }
     }
 
     return next(action);
 });
+
+/**
+ * Displays a UI notification for screensharing failure based on the error passed.
+ *
+ * @private
+ * @param {Object} error - The error.
+ * @param {Object} store - The redux store.
+ * @returns {void}
+ */
+function _handleScreensharingError(error, { dispatch }) {
+    if (error.name === JitsiTrackErrors.SCREENSHARING_USER_CANCELED) {
+        return;
+    }
+    let descriptionKey, titleKey;
+
+    if (error.name === JitsiTrackErrors.PERMISSION_DENIED) {
+        descriptionKey = 'dialog.screenSharingPermissionDeniedError';
+        titleKey = 'dialog.screenSharingFailedTitle';
+    } else if (error.name === JitsiTrackErrors.CONSTRAINT_FAILED) {
+        descriptionKey = 'dialog.cameraConstraintFailedError';
+        titleKey = 'deviceError.cameraError';
+    } else if (error.name === JitsiTrackErrors.SCREENSHARING_GENERIC_ERROR) {
+        descriptionKey = 'dialog.screenSharingFailed';
+        titleKey = 'dialog.screenSharingFailedTitle';
+    } else if (error === AUDIO_ONLY_SCREEN_SHARE_NO_TRACK) {
+        descriptionKey = 'notify.screenShareNoAudio';
+        titleKey = 'notify.screenShareNoAudioTitle';
+    }
+
+    dispatch(showNotification({
+        titleKey,
+        descriptionKey
+    }, NOTIFICATION_TIMEOUT_TYPE.MEDIUM));
+}
+
+/**
+ * Applies the AudioMixer effect on the local audio track if applicable. If there is no local audio track, the desktop
+ * audio track is added to the conference.
+ *
+ * @private
+ * @param {JitsiLocalTrack} desktopAudioTrack - The audio track to be added to the conference.
+ * @param {*} state - The redux state.
+ * @returns {void}
+ */
+async function _maybeApplyAudioMixerEffect(desktopAudioTrack, state) {
+    const localAudio = getLocalJitsiAudioTrack(state);
+    const conference = getCurrentConference(state);
+
+    if (localAudio) {
+        // If there is a localAudio stream, mix in the desktop audio stream captured by the screen sharing API.
+        const mixerEffect = new AudioMixerEffect(desktopAudioTrack);
+
+        await localAudio.setEffect(mixerEffect);
+    } else {
+        // If no local stream is present ( i.e. no input audio devices) we use the screen share audio
+        // stream as we would use a regular stream.
+        await conference.replaceTrack(null, desktopAudioTrack);
+    }
+}
+
+/**
+ * Toggles screen sharing.
+ *
+ * @private
+ * @param {boolean} enabled - The state to toggle screen sharing to.
+ * @param {Store} store - The redux store.
+ * @returns {void}
+ */
+async function _toggleScreenSharing({ enabled, audioOnly = false }, store) {
+    const { dispatch, getState } = store;
+    const state = getState();
+    const conference = getCurrentConference(state);
+    const localAudio = getLocalJitsiAudioTrack(state);
+    const localScreenshare = getLocalDesktopTrack(state['features/base/tracks']);
+
+    if (enabled) {
+        let tracks;
+
+        try {
+            tracks = await createLocalTracksF({ devices: [ VIDEO_TYPE.DESKTOP ] });
+        } catch (error) {
+            _handleScreensharingError(error, store);
+
+            return;
+        }
+        const desktopAudioTrack = tracks.find(track => track.getType() === MEDIA_TYPE.AUDIO);
+        const desktopVideoTrack = tracks.find(track => track.getType() === MEDIA_TYPE.VIDEO);
+
+        // Dispose the desktop track for audio-only screensharing.
+        if (audioOnly) {
+            desktopVideoTrack.dispose();
+
+            if (!desktopAudioTrack) {
+                _handleScreensharingError(AUDIO_ONLY_SCREEN_SHARE_NO_TRACK, store);
+
+                return;
+            }
+        } else if (desktopVideoTrack) {
+            if (localScreenshare) {
+                await dispatch(replaceLocalTrack(localScreenshare.jitsiTrack, desktopVideoTrack, conference));
+            } else {
+                await dispatch(addLocalTrack(desktopVideoTrack));
+            }
+        }
+
+        // Apply the AudioMixer effect if there is a local audio track, add the desktop track to the conference
+        // otherwise without unmuting the microphone.
+        if (desktopAudioTrack) {
+            _maybeApplyAudioMixerEffect(desktopAudioTrack, state);
+            dispatch(setScreenshareAudioTrack(desktopAudioTrack));
+        }
+
+        // Disable audio-only or best performance mode if the user starts screensharing. This doesn't apply to
+        // audio-only screensharing.
+        const { enabled: bestPerformanceMode } = state['features/base/audio-only'];
+
+        if (bestPerformanceMode && !audioOnly) {
+            dispatch(setAudioOnly(false));
+        }
+    } else {
+        const { desktopAudioTrack } = state['features/screen-share'];
+
+        // Mute the desktop track instead of removing it from the conference since we don't want the client to signal
+        // a source-remove to the remote peer for the screenshare track. Later when screenshare is enabled again, the
+        // same sender will be re-used without the need for signaling a new ssrc through source-add.
+        dispatch(setScreenshareMuted(true));
+        if (desktopAudioTrack) {
+            if (localAudio) {
+                localAudio.setEffect(undefined);
+            } else {
+                await conference.replaceTrack(desktopAudioTrack, null);
+            }
+            desktopAudioTrack.dispose();
+            dispatch(setScreenshareAudioTrack(null));
+        }
+    }
+
+    if (audioOnly) {
+        dispatch(setScreenAudioShareState(enabled));
+    }
+}

react/features/base/config/constants.js

@@ -67,5 +67,6 @@ export const THIRD_PARTY_PREJOIN_BUTTONS = [ 'microphone', 'camera', 'select-bac
  */
 
 export const FEATURE_FLAGS = {
+    MULTIPLE_VIDEO_STREAMS_SUPPORT: 'sendMultipleVideoStreams',
     SOURCE_NAME_SIGNALING: 'sourceNameSignaling'
 };

react/features/base/config/functions.any.js

@@ -4,6 +4,7 @@ import Bourne from '@hapi/bourne';
 import { jitsiLocalStorage } from '@jitsi/js-utils';
 import _ from 'lodash';
 
+import { browser } from '../lib-jitsi-meet';
 import { parseURLParams } from '../util';
 
 import CONFIG_WHITELIST from './configWhitelist';
@@ -49,6 +50,18 @@ export function getMeetingRegion(state: Object) {
     return state['features/base/config']?.deploymentInfo?.region || '';
 }
 
+/**
+ * Selector used to get the sendMultipleVideoStreams feature flag.
+ *
+ * @param {Object} state - The global state.
+ * @returns {boolean}
+ */
+export function getMultipleVideoSupportFeatureFlag(state: Object) {
+    return getFeatureFlag(state, FEATURE_FLAGS.MULTIPLE_VIDEO_STREAMS_SUPPORT)
+        && getSourceNameSignalingFeatureFlag(state)
+        && isUnifiedPlanEnabled(state);
+}
+
 /**
  * Selector used to get the sourceNameSignaling feature flag.
  *
@@ -196,6 +209,19 @@ export function isDisplayNameVisible(state: Object): boolean {
     return !state['features/base/config'].hideDisplayName;
 }
 
+/**
+ * Selector for determining if Unified plan support is enabled.
+ *
+ * @param {Object} state - The state of the app.
+ * @returns {boolean}
+ */
+export function isUnifiedPlanEnabled(state: Object): boolean {
+    const { enableUnifiedOnChrome = true } = state['features/base/config'];
+
+    return browser.supportsUnifiedPlan()
+        && (!browser.isChromiumBased() || (browser.isChromiumBased() && enableUnifiedOnChrome));
+}
+
 /**
  * Restores a Jitsi Meet config.js from {@code localStorage} if it was
  * previously downloaded from a specific {@code baseURL} and stored with

react/features/base/media/actionTypes.js

@@ -40,6 +40,16 @@ export const SET_AUDIO_UNMUTE_PERMISSIONS = 'SET_AUDIO_UNMUTE_PERMISSIONS';
  */
 export const SET_CAMERA_FACING_MODE = 'SET_CAMERA_FACING_MODE';
 
+/**
+ * The type of (redux) action to set the muted state of the local screenshare.
+ *
+ * {
+ *     type: SET_SCREENSHARE_MUTED,
+ *     muted: boolean
+ * }
+ */
+export const SET_SCREENSHARE_MUTED = 'SET_SCREENSHARE_MUTED';
+
 /**
  * The type of (redux) action to adjust the availability of the local video.
  *

react/features/base/media/actions.js

@@ -11,6 +11,7 @@ import {
     SET_AUDIO_AVAILABLE,
     SET_AUDIO_UNMUTE_PERMISSIONS,
     SET_CAMERA_FACING_MODE,
+    SET_SCREENSHARE_MUTED,
     SET_VIDEO_AVAILABLE,
     SET_VIDEO_MUTED,
     SET_VIDEO_UNMUTE_PERMISSIONS,
@@ -20,6 +21,7 @@ import {
 import {
     MEDIA_TYPE,
     type MediaType,
+    SCREENSHARE_MUTISM_AUTHORITY,
     VIDEO_MUTISM_AUTHORITY
 } from './constants';
 
@@ -92,6 +94,47 @@ export function setCameraFacingMode(cameraFacingMode: string) {
     };
 }
 
+/**
+ * Action to set the muted state of the local screenshare.
+ *
+ * @param {boolean} muted - True if the local screenshare is to be enabled or false otherwise.
+ * @param {MEDIA_TYPE} mediaType - The type of media.
+ * @param {number} authority - The {@link SCREENSHARE_MUTISM_AUTHORITY} which is muting/unmuting the local screenshare.
+ * @param {boolean} ensureTrack - True if we want to ensure that a new track is created if missing.
+ * @returns {Function}
+ */
+export function setScreenshareMuted(
+        muted: boolean,
+        mediaType: MediaType = MEDIA_TYPE.SCREENSHARE,
+        authority: number = SCREENSHARE_MUTISM_AUTHORITY.USER,
+        ensureTrack: boolean = false) {
+    return (dispatch: Dispatch<any>, getState: Function) => {
+        const state = getState();
+
+        // check for A/V Moderation when trying to unmute
+        if (!muted && shouldShowModeratedNotification(MEDIA_TYPE.SCREENSHARE, state)) {
+            if (!isModerationNotificationDisplayed(MEDIA_TYPE.SCREENSHARE, state)) {
+                ensureTrack && dispatch(showModeratedNotification(MEDIA_TYPE.SCREENSHARE));
+            }
+
+            return;
+        }
+
+        const oldValue = state['features/base/media'].screenshare.muted;
+
+        // eslint-disable-next-line no-bitwise
+        const newValue = muted ? oldValue | authority : oldValue & ~authority;
+
+        return dispatch({
+            type: SET_SCREENSHARE_MUTED,
+            authority,
+            mediaType,
+            ensureTrack,
+            muted: newValue
+        });
+    };
+}
+
 /**
  * Action to adjust the availability of the local video.
  *

react/features/base/media/constants.js

@@ -10,7 +10,7 @@ export const CAMERA_FACING_MODE = {
     USER: 'user'
 };
 
-export type MediaType = 'audio' | 'video' | 'presenter';
+export type MediaType = 'audio' | 'video' | 'presenter' | 'screenshare';
 
 /**
  * The set of media types.
@@ -20,12 +20,23 @@ export type MediaType = 'audio' | 'video' | 'presenter';
 export const MEDIA_TYPE = {
     AUDIO: 'audio',
     PRESENTER: 'presenter',
+    SCREENSHARE: 'screenshare',
     VIDEO: 'video'
 };
 
 
 /* eslint-disable no-bitwise */
 
+/**
+ * The types of authorities which may mute/unmute the local screenshare.
+ *
+ * @enum {number}
+ */
+export const SCREENSHARE_MUTISM_AUTHORITY = {
+    AUDIO_ONLY: 1 << 0,
+    USER: 1 << 2
+};
+
 /**
  * The types of authorities which may mute/unmute the local video.
  *

react/features/base/media/middleware.js

@@ -16,6 +16,7 @@ import { isForceMuted } from '../../participants-pane/functions';
 import { isScreenMediaShared } from '../../screen-share/functions';
 import { SET_AUDIO_ONLY, setAudioOnly } from '../audio-only';
 import { isRoomValid, SET_ROOM } from '../conference';
+import { getMultipleVideoSupportFeatureFlag } from '../config';
 import { getLocalParticipant } from '../participants';
 import { MiddlewareRegistry } from '../redux';
 import { getPropertyValue } from '../settings';
@@ -30,13 +31,20 @@ import {
 import {
     SET_AUDIO_MUTED,
     SET_AUDIO_UNMUTE_PERMISSIONS,
+    SET_SCREENSHARE_MUTED,
     SET_VIDEO_MUTED,
     SET_VIDEO_UNMUTE_PERMISSIONS
 } from './actionTypes';
-import { setAudioMuted, setCameraFacingMode, setVideoMuted } from './actions';
+import {
+    setAudioMuted,
+    setCameraFacingMode,
+    setScreenshareMuted,
+    setVideoMuted
+} from './actions';
 import {
     CAMERA_FACING_MODE,
     MEDIA_TYPE,
+    SCREENSHARE_MUTISM_AUTHORITY,
     VIDEO_MUTISM_AUTHORITY
 } from './constants';
 import { getStartWithAudioMuted, getStartWithVideoMuted } from './functions';
@@ -100,6 +108,15 @@ MiddlewareRegistry.register(store => next => action => {
         break;
     }
 
+    case SET_SCREENSHARE_MUTED: {
+        const state = store.getState();
+        const participant = getLocalParticipant(state);
+
+        if (!action.muted && isForceMuted(participant, MEDIA_TYPE.SCREENSHARE, state)) {
+            return;
+        }
+        break;
+    }
     case SET_VIDEO_MUTED: {
         const state = store.getState();
         const participant = getLocalParticipant(state);
@@ -167,15 +184,17 @@ function _appStateChanged({ dispatch, getState }, next, action) {
  * @private
  * @returns {Object} The value returned by {@code next(action)}.
  */
-function _setAudioOnly({ dispatch }, next, action) {
+function _setAudioOnly({ dispatch, getState }, next, action) {
     const { audioOnly, ensureVideoTrack } = action;
+    const state = getState();
 
     sendAnalytics(createTrackMutedEvent('video', 'audio-only mode', audioOnly));
 
     // Make sure we mute both the desktop and video tracks.
     dispatch(setVideoMuted(audioOnly, MEDIA_TYPE.VIDEO, VIDEO_MUTISM_AUTHORITY.AUDIO_ONLY, ensureVideoTrack));
-
-    if (navigator.product !== 'ReactNative') {
+    if (getMultipleVideoSupportFeatureFlag(state)) {
+        dispatch(setScreenshareMuted(audioOnly, MEDIA_TYPE.SCREENSHARE, SCREENSHARE_MUTISM_AUTHORITY.AUDIO_ONLY));
+    } else if (navigator.product !== 'ReactNative') {
         dispatch(setVideoMuted(audioOnly, MEDIA_TYPE.PRESENTER, VIDEO_MUTISM_AUTHORITY.AUDIO_ONLY, ensureVideoTrack));
     }
 
@@ -292,11 +311,9 @@ function _syncTrackMutedState({ getState }, track) {
     // fired before track gets to state.
     if (track.muted !== muted) {
         sendAnalytics(createSyncTrackStateEvent(track.mediaType, muted));
-        logger.log(
-            `Sync ${track.mediaType} track muted state to ${
-                muted ? 'muted' : 'unmuted'}`);
+        logger.log(`Sync ${track.mediaType} track muted state to ${muted ? 'muted' : 'unmuted'}`);
 
         track.muted = muted;
-        setTrackMuted(track.jitsiTrack, muted);
+        setTrackMuted(track.jitsiTrack, muted, state);
     }
 }

react/features/base/media/reducer.js

@@ -9,13 +9,14 @@ import {
     SET_AUDIO_MUTED,
     SET_AUDIO_UNMUTE_PERMISSIONS,
     SET_CAMERA_FACING_MODE,
+    SET_SCREENSHARE_MUTED,
     SET_VIDEO_AVAILABLE,
     SET_VIDEO_MUTED,
     SET_VIDEO_UNMUTE_PERMISSIONS,
     STORE_VIDEO_TRANSFORM,
     TOGGLE_CAMERA_FACING_MODE
 } from './actionTypes';
-import { CAMERA_FACING_MODE } from './constants';
+import { CAMERA_FACING_MODE, SCREENSHARE_MUTISM_AUTHORITY } from './constants';
 
 /**
  * Media state object for local audio.
@@ -73,6 +74,54 @@ function _audio(state = _AUDIO_INITIAL_MEDIA_STATE, action) {
     }
 }
 
+/**
+ * Media state object for local screenshare.
+ *
+ * @typedef {Object} ScreenshareMediaState
+ * @property {boolean} available=true - Screenshare available state.
+ * @property {boolean} muted=true - Screenshare muted state.
+ * @property {boolean} unmuteBlocked=false - Screenshare unmute blocked state.
+ */
+
+/**
+ * Initial state for video.
+ *
+ * @type {ScreenshareMediaState}
+ */
+export const _SCREENSHARE_INITIAL_MEDIA_STATE = {
+    available: true,
+    muted: SCREENSHARE_MUTISM_AUTHORITY.USER,
+    unmuteBlocked: false
+};
+
+/**
+ * Reducer for screenshare media state.
+ *
+ * @param {VideoMediaState} state - Media state of local screenshare.
+ * @param {Object} action - Action object.
+ * @param {string} action.type - Type of action.
+ * @private
+ * @returns {ScreenshareMediaState}
+ */
+function _screenshare(state = _SCREENSHARE_INITIAL_MEDIA_STATE, action) {
+    switch (action.type) {
+    case SET_SCREENSHARE_MUTED:
+        return {
+            ...state,
+            muted: action.muted
+        };
+
+    case SET_VIDEO_UNMUTE_PERMISSIONS:
+        return {
+            ...state,
+            unmuteBlocked: action.blocked
+        };
+
+    default:
+        return state;
+    }
+}
+
 /**
  * Media state object for local video.
  *
@@ -179,6 +228,7 @@ function _video(state = _VIDEO_INITIAL_MEDIA_STATE, action) {
  */
 ReducerRegistry.register('features/base/media', combineReducers({
     audio: _audio,
+    screenshare: _screenshare,
     video: _video
 }));
 

react/features/base/tracks/actionTypes.js

@@ -54,6 +54,18 @@ export const TRACK_CREATE_CANCELED = 'TRACK_CREATE_CANCELED';
  */
 export const TRACK_CREATE_ERROR = 'TRACK_CREATE_ERROR';
 
+/**
+ * The type of redux action dispatched when the track mute/unmute operation fails at the conference level. This could
+ * happen because of {@code getUserMedia} errors during unmute or replace track errors at the peerconnection level.
+ *
+ * {
+ *     type: TRACK_MUTE_UNMUTE_FAILED,
+ *     track: Track,
+ *     wasMuting: Boolean
+ * }
+ */
+export const TRACK_MUTE_UNMUTE_FAILED = 'TRACK_MUTE_UNMUTE_FAILED';
+
 /**
  * The type of redux action dispatched when a track has triggered no data from source event.
  *

react/features/base/tracks/actions.js

@@ -5,11 +5,14 @@ import {
     sendAnalytics
 } from '../../analytics';
 import { NOTIFICATION_TIMEOUT_TYPE, showErrorNotification, showNotification } from '../../notifications';
+import { getCurrentConference } from '../conference';
+import { getMultipleVideoSupportFeatureFlag } from '../config';
 import { JitsiTrackErrors, JitsiTrackEvents, createLocalTrack } from '../lib-jitsi-meet';
 import {
     CAMERA_FACING_MODE,
     MEDIA_TYPE,
     setAudioMuted,
+    setScreenshareMuted,
     setVideoMuted,
     VIDEO_MUTISM_AUTHORITY,
     VIDEO_TYPE
@@ -23,6 +26,7 @@ import {
     TRACK_ADDED,
     TRACK_CREATE_CANCELED,
     TRACK_CREATE_ERROR,
+    TRACK_MUTE_UNMUTE_FAILED,
     TRACK_NO_DATA_FROM_SOURCE,
     TRACK_REMOVED,
     TRACK_STOPPED,
@@ -39,6 +43,35 @@ import {
 } from './functions';
 import logger from './logger';
 
+/**
+ * Add a given local track to the conference.
+ *
+ * @param {JitsiLocalTrack} newTrack - The local track to be added to the conference.
+ * @returns {Function}
+ */
+export function addLocalTrack(newTrack) {
+    return async (dispatch, getState) => {
+        const conference = getCurrentConference(getState());
+
+        if (conference) {
+            await conference.addTrack(newTrack);
+        }
+
+        const setMuted = newTrack.isVideoTrack()
+            ? getMultipleVideoSupportFeatureFlag(getState())
+            && newTrack.getVideoType() === VIDEO_TYPE.DESKTOP
+                ? setScreenshareMuted
+                : setVideoMuted
+            : setAudioMuted;
+        const isMuted = newTrack.isMuted();
+
+        logger.log(`Adding ${newTrack.getType()} track - ${isMuted ? 'muted' : 'unmuted'}`);
+        await dispatch(setMuted(isMuted));
+
+        return dispatch(_addTracks([ newTrack ]));
+    };
+}
+
 /**
  * Requests the creating of the desired media type tracks. Desire is expressed
  * by base/media unless the function caller specifies desired media types
@@ -320,49 +353,34 @@ export function replaceLocalTrack(oldTrack, newTrack, conference) {
  * @returns {Function}
  */
 function replaceStoredTracks(oldTrack, newTrack) {
-    return dispatch => {
+    return async (dispatch, getState) => {
         // We call dispose after doing the replace because dispose will
         // try and do a new o/a after the track removes itself. Doing it
         // after means the JitsiLocalTrack.conference is already
         // cleared, so it won't try and do the o/a.
-        const disposePromise
-              = oldTrack
-                  ? dispatch(_disposeAndRemoveTracks([ oldTrack ]))
-                  : Promise.resolve();
+        if (oldTrack) {
+            await dispatch(_disposeAndRemoveTracks([ oldTrack ]));
+        }
 
-        return disposePromise
-            .then(() => {
         if (newTrack) {
-                    // The mute state of the new track should be
-                    // reflected in the app's mute state. For example,
-                    // if the app is currently muted and changing to a
-                    // new track that is not muted, the app's mute
-                    // state should be falsey. As such, emit a mute
-                    // event here to set up the app to reflect the
-                    // track's mute state. If this is not done, the
-                    // current mute state of the app will be reflected
-                    // on the track, not vice-versa.
-                    const setMuted
-                          = newTrack.isVideoTrack()
-                              ? setVideoMuted
+            // The mute state of the new track should be reflected in the app's mute state. For example, if the
+            // app is currently muted and changing to a new track that is not muted, the app's mute state
+            // should be falsey. As such, emit a mute event here to set up the app to reflect the track's mute
+            // state. If this is not done, the current mute state of the app will be reflected on the track,
+            // not vice-versa.
+            const setMuted = newTrack.isVideoTrack()
+                ? getMultipleVideoSupportFeatureFlag(getState()) && newTrack.getVideoType() === VIDEO_TYPE.DESKTOP
+                    ? setScreenshareMuted
+                    : setVideoMuted
                 : setAudioMuted;
             const isMuted = newTrack.isMuted();
 
-                    sendAnalytics(createTrackMutedEvent(
-                        newTrack.getType(),
-                        'track.replaced',
-                        isMuted));
-                    logger.log(`Replace ${newTrack.getType()} track - ${
-                        isMuted ? 'muted' : 'unmuted'}`);
+            sendAnalytics(createTrackMutedEvent(newTrack.getType(), 'track.replaced', isMuted));
+            logger.log(`Replace ${newTrack.getType()} track - ${isMuted ? 'muted' : 'unmuted'}`);
 
-                    return dispatch(setMuted(isMuted));
+            await dispatch(setMuted(isMuted));
+            await dispatch(_addTracks([ newTrack ]));
         }
-            })
-            .then(() => {
-                if (newTrack) {
-                    return dispatch(_addTracks([ newTrack ]));
-                }
-            });
     };
 }
 
@@ -384,7 +402,9 @@ export function trackAdded(track) {
 
         // participantId
         const local = track.isLocal();
-        const mediaType = track.getType();
+        const mediaType = getMultipleVideoSupportFeatureFlag(getState()) && track.getVideoType() === VIDEO_TYPE.DESKTOP
+            ? MEDIA_TYPE.SCREENSHARE
+            : track.getType();
         let isReceivingData, noDataFromSourceNotificationInfo, participantId;
 
         if (local) {
@@ -471,6 +491,25 @@ export function trackMutedChanged(track) {
     };
 }
 
+/**
+ * Create an action for when a track's muted state change action has failed. This could happen because of
+ * {@code getUserMedia} errors during unmute or replace track errors at the peerconnection level.
+ *
+ * @param {(JitsiLocalTrack|JitsiRemoteTrack)} track - JitsiTrack instance.
+ * @param {boolean} wasMuting - If the operation that failed was a mute operation or an unmute operation.
+ * @returns {{
+ *     type: TRACK_MUTE_UNMUTE_FAILED,
+ *     track: Track
+ * }}
+ */
+export function trackMuteUnmuteFailed(track, wasMuting) {
+    return {
+        type: TRACK_MUTE_UNMUTE_FAILED,
+        track,
+        wasMuting
+    };
+}
+
 /**
  * Create an action for when a track's no data from source notification information changes.
  *

react/features/base/tracks/functions.js

@@ -1,5 +1,6 @@
 /* global APP */
 
+import { getMultipleVideoSupportFeatureFlag } from '../config/functions.any';
 import { isMobileBrowser } from '../environment/utils';
 import JitsiMeetJS, { JitsiTrackErrors, browser } from '../lib-jitsi-meet';
 import { MEDIA_TYPE, VIDEO_TYPE, setAudioMuted } from '../media';
@@ -295,6 +296,33 @@ export function getLocalAudioTrack(tracks) {
     return getLocalTrack(tracks, MEDIA_TYPE.AUDIO);
 }
 
+/**
+ * Returns the local desktop track.
+ *
+ * @param {Track[]} tracks - List of all tracks.
+ * @param {boolean} [includePending] - Indicates whether a local track is to be returned if it is still pending.
+ * A local track is pending if {@code getUserMedia} is still executing to create it and, consequently, its
+ * {@code jitsiTrack} property is {@code undefined}. By default a pending local track is not returned.
+ * @returns {(Track|undefined)}
+ */
+export function getLocalDesktopTrack(tracks, includePending = false) {
+    return (
+        getLocalTracks(tracks, includePending)
+            .find(t => t.mediaType === MEDIA_TYPE.SCREENSHARE || t.videoType === VIDEO_TYPE.DESKTOP));
+}
+
+/**
+ * Returns the stored local desktop jitsiLocalTrack.
+ *
+ * @param {Object} state - The redux state.
+ * @returns {JitsiLocalTrack|undefined}
+ */
+export function getLocalJitsiDesktopTrack(state) {
+    const track = getLocalDesktopTrack(getTrackState(state));
+
+    return track?.jitsiTrack;
+}
+
 /**
  * Returns local track by media type.
  *
@@ -524,20 +552,22 @@ export function isUserInteractionRequiredForUnmute(state) {
 }
 
 /**
- * Mutes or unmutes a specific {@code JitsiLocalTrack}. If the muted state of
- * the specified {@code track} is already in accord with the specified
- * {@code muted} value, then does nothing.
+ * Mutes or unmutes a specific {@code JitsiLocalTrack}. If the muted state of the specified {@code track} is already in
+ * accord with the specified {@code muted} value, then does nothing.
  *
- * @param {JitsiLocalTrack} track - The {@code JitsiLocalTrack} to mute or
- * unmute.
- * @param {boolean} muted - If the specified {@code track} is to be muted, then
- * {@code true}; otherwise, {@code false}.
+ * @param {JitsiLocalTrack} track - The {@code JitsiLocalTrack} to mute or unmute.
+ * @param {boolean} muted - If the specified {@code track} is to be muted, then {@code true}; otherwise, {@code false}.
+ * @param {Object} state - The redux state.
  * @returns {Promise}
  */
-export function setTrackMuted(track, muted) {
+export function setTrackMuted(track, muted, state) {
     muted = Boolean(muted); // eslint-disable-line no-param-reassign
 
-    if (track.isMuted() === muted) {
+    // Ignore the check for desktop track muted operation. When the screenshare is terminated by clicking on the
+    // browser's 'Stop sharing' button, the local stream is stopped before the inactive stream handler is fired.
+    // We still need to proceed here and remove the track from the peerconnection.
+    if (track.isMuted() === muted
+        && !(track.getVideoType() === VIDEO_TYPE.DESKTOP && getMultipleVideoSupportFeatureFlag(state))) {
         return Promise.resolve();
     }
 
@@ -546,8 +576,9 @@ export function setTrackMuted(track, muted) {
     return track[f]().catch(error => {
         // Track might be already disposed so ignore such an error.
         if (error.name !== JitsiTrackErrors.TRACK_IS_DISPOSED) {
-            // FIXME Emit mute failed, so that the app can show error dialog.
             logger.error(`set track ${f} failed`, error);
+
+            return Promise.reject(error);
         }
     });
 }

react/features/base/tracks/middleware.js

@@ -8,6 +8,7 @@ import { shouldShowModeratedNotification } from '../../av-moderation/functions';
 import { hideNotification, isModerationNotificationDisplayed } from '../../notifications';
 import { isPrejoinPageVisible } from '../../prejoin/functions';
 import { getCurrentConference } from '../conference/functions';
+import { getMultipleVideoSupportFeatureFlag } from '../config';
 import { getAvailableDevices } from '../devices/actions';
 import {
     CAMERA_FACING_MODE,
@@ -18,15 +19,20 @@ import {
     VIDEO_MUTISM_AUTHORITY,
     TOGGLE_CAMERA_FACING_MODE,
     toggleCameraFacingMode,
-    VIDEO_TYPE
+    SET_SCREENSHARE_MUTED,
+    VIDEO_TYPE,
+    setScreenshareMuted,
+    SCREENSHARE_MUTISM_AUTHORITY
 } from '../media';
 import { MiddlewareRegistry, StateListenerRegistry } from '../redux';
 
 import {
-    TRACK_ADDED,
     TOGGLE_SCREENSHARING,
+    TRACK_ADDED,
+    TRACK_MUTE_UNMUTE_FAILED,
     TRACK_NO_DATA_FROM_SOURCE,
     TRACK_REMOVED,
+    TRACK_STOPPED,
     TRACK_UPDATED
 } from './actionTypes';
 import {
@@ -34,6 +40,7 @@ import {
     destroyLocalTracks,
     showNoDataFromSourceVideoError,
     toggleScreensharing,
+    trackMuteUnmuteFailed,
     trackRemoved,
     trackNoDataFromSourceNotificationInfoChanged
 } from './actions';
@@ -107,6 +114,10 @@ MiddlewareRegistry.register(store => next => action => {
         break;
     }
 
+    case SET_SCREENSHARE_MUTED:
+        _setMuted(store, action, action.mediaType);
+        break;
+
     case SET_VIDEO_MUTED:
         if (!action.muted
                 && isUserInteractionRequiredForUnmute(store.getState())) {
@@ -156,19 +167,54 @@ MiddlewareRegistry.register(store => next => action => {
 
             const { enabled, audioOnly, ignoreDidHaveVideo } = action;
 
-            APP.UI.emitEvent(UIEvents.TOGGLE_SCREENSHARING, { enabled,
+            if (!getMultipleVideoSupportFeatureFlag(store.getState())) {
+                APP.UI.emitEvent(UIEvents.TOGGLE_SCREENSHARING,
+                    {
+                        enabled,
                         audioOnly,
-                ignoreDidHaveVideo });
+                        ignoreDidHaveVideo
+                    });
+            }
         }
         break;
 
+    case TRACK_MUTE_UNMUTE_FAILED: {
+        const { jitsiTrack } = action.track;
+        const muted = action.wasMuted;
+        const isVideoTrack = jitsiTrack.getType() !== MEDIA_TYPE.AUDIO;
+
+        if (typeof APP !== 'undefined') {
+            if (isVideoTrack && jitsiTrack.getVideoType() === VIDEO_TYPE.DESKTOP
+                && getMultipleVideoSupportFeatureFlag(store.getState())) {
+                store.dispatch(setScreenshareMuted(!muted));
+            } else if (isVideoTrack) {
+                APP.conference.setVideoMuteStatus();
+            } else {
+                APP.conference.setAudioMuteStatus(!muted);
+            }
+        }
+        break;
+    }
+
+    case TRACK_STOPPED: {
+        const { jitsiTrack } = action.track;
+
+        if (typeof APP !== 'undefined'
+            && getMultipleVideoSupportFeatureFlag(store.getState())
+            && jitsiTrack.getVideoType() === VIDEO_TYPE.DESKTOP) {
+            store.dispatch(toggleScreensharing(false));
+        }
+        break;
+    }
+
     case TRACK_UPDATED: {
         // TODO Remove the following calls to APP.UI once components interested
         // in track mute changes are moved into React and/or redux.
         if (typeof APP !== 'undefined') {
             const result = next(action);
+            const state = store.getState();
 
-            if (isPrejoinPageVisible(store.getState())) {
+            if (isPrejoinPageVisible(state)) {
                 return result;
             }
 
@@ -181,10 +227,11 @@ MiddlewareRegistry.register(store => next => action => {
                 // Do not change the video mute state for local presenter tracks.
                 if (jitsiTrack.type === MEDIA_TYPE.PRESENTER) {
                     APP.conference.mutePresenter(muted);
-                } else if (jitsiTrack.isLocal() && !(jitsiTrack.videoType === VIDEO_TYPE.DESKTOP)) {
+                } else if (jitsiTrack.isLocal() && !(jitsiTrack.getVideoType() === VIDEO_TYPE.DESKTOP)) {
                     APP.conference.setVideoMuteStatus();
-                } else if (jitsiTrack.isLocal() && muted && jitsiTrack.videoType === VIDEO_TYPE.DESKTOP) {
-                    store.dispatch(toggleScreensharing(false, false, true));
+                } else if (jitsiTrack.isLocal() && muted && jitsiTrack.getVideoType() === VIDEO_TYPE.DESKTOP) {
+                    !getMultipleVideoSupportFeatureFlag(state)
+                        && store.dispatch(toggleScreensharing(false, false, true));
                 } else {
                     APP.UI.setVideoMuted(participantID);
                 }
@@ -335,25 +382,34 @@ function _removeNoDataFromSourceNotification({ getState, dispatch }, track) {
  * @private
  * @returns {void}
  */
-function _setMuted(store, { ensureTrack, authority, muted }, mediaType: MEDIA_TYPE) {
-    const localTrack
-        = _getLocalTrack(store, mediaType, /* includePending */ true);
+async function _setMuted(store, { ensureTrack, authority, muted }, mediaType: MEDIA_TYPE) {
+    const { dispatch, getState } = store;
+    const localTrack = _getLocalTrack(store, mediaType, /* includePending */ true);
+    const state = getState();
+
+    if (mediaType === MEDIA_TYPE.SCREENSHARE
+        && getMultipleVideoSupportFeatureFlag(state)
+        && !muted) {
+        return;
+    }
 
     if (localTrack) {
-        // The `jitsiTrack` property will have a value only for a localTrack for
-        // which `getUserMedia` has already completed. If there's no
-        // `jitsiTrack`, then the `muted` state will be applied once the
-        // `jitsiTrack` is created.
+        // The `jitsiTrack` property will have a value only for a localTrack for which `getUserMedia` has already
+        // completed. If there's no `jitsiTrack`, then the `muted` state will be applied once the `jitsiTrack` is
+        // created.
         const { jitsiTrack } = localTrack;
-        const isAudioOnly = authority === VIDEO_MUTISM_AUTHORITY.AUDIO_ONLY;
+        const isAudioOnly = (mediaType === MEDIA_TYPE.VIDEO && authority === VIDEO_MUTISM_AUTHORITY.AUDIO_ONLY)
+            || (mediaType === MEDIA_TYPE.SCREENSHARE && authority === SCREENSHARE_MUTISM_AUTHORITY.AUDIO_ONLY);
 
-        // screenshare cannot be muted or unmuted using the video mute button
-        // anymore, unless it is muted by audioOnly.
-        jitsiTrack && (jitsiTrack.videoType !== 'desktop' || isAudioOnly)
-            && setTrackMuted(jitsiTrack, muted);
-    } else if (!muted && ensureTrack && (typeof APP === 'undefined' || isPrejoinPageVisible(store.getState()))) {
+        // Screenshare cannot be unmuted using the video mute button unless it is muted by audioOnly in the legacy
+        // screensharing mode.
+        if (jitsiTrack
+            && (jitsiTrack.videoType !== 'desktop' || isAudioOnly || getMultipleVideoSupportFeatureFlag(state))) {
+            setTrackMuted(jitsiTrack, muted, state).catch(() => dispatch(trackMuteUnmuteFailed(localTrack, muted)));
+        }
+    } else if (!muted && ensureTrack && (typeof APP === 'undefined' || isPrejoinPageVisible(state))) {
         // FIXME: This only runs on mobile now because web has its own way of
         // creating local tracks. Adjust the check once they are unified.
-        store.dispatch(createLocalTracksA({ devices: [ mediaType ] }));
+        dispatch(createLocalTracksA({ devices: [ mediaType ] }));
     }
 }

react/features/screen-share/actionTypes.js

@@ -18,3 +18,12 @@ export const SET_SCREEN_AUDIO_SHARE_STATE = 'SET_SCREEN_AUDIO_SHARE_STATE';
  * }
  */
 export const SET_SCREENSHARE_CAPTURE_FRAME_RATE = 'SET_SCREENSHARE_CAPTURE_FRAME_RATE';
+
+/**
+ * Type of action which sets the current audio track captured from the screenshare.
+ * {
+ *      type: SET_SCREENSHARE_TRACKS,
+ *      desktopAudioTrack: JitsiTrack
+ * }
+ */
+export const SET_SCREENSHARE_TRACKS = 'SET_SCREENSHARE_TRACKS';

react/features/screen-share/actions.js

@@ -1,11 +1,16 @@
 // @flow
 
+import { getMultipleVideoSupportFeatureFlag } from '../base/config/functions.any';
 import { openDialog } from '../base/dialog/actions';
 import { browser } from '../base/lib-jitsi-meet';
 import { shouldHideShareAudioHelper } from '../base/settings';
 import { toggleScreensharing } from '../base/tracks';
 
-import { SET_SCREEN_AUDIO_SHARE_STATE, SET_SCREENSHARE_CAPTURE_FRAME_RATE } from './actionTypes';
+import {
+    SET_SCREEN_AUDIO_SHARE_STATE,
+    SET_SCREENSHARE_CAPTURE_FRAME_RATE,
+    SET_SCREENSHARE_TRACKS
+} from './actionTypes';
 import { ShareAudioDialog } from './components';
 import ShareMediaWarningDialog from './components/ShareScreenWarningDialog';
 import { isAudioOnlySharing, isScreenVideoShared } from './functions';
@@ -42,6 +47,22 @@ export function setScreenshareFramerate(captureFrameRate: number) {
     };
 }
 
+/**
+ * Updates the audio track associated with the screenshare.
+ *
+ * @param {JitsiLocalTrack} desktopAudioTrack - The audio track captured from the screenshare.
+ * @returns {{
+ *      type: SET_SCREENSHARE_TRACKS,
+ *      desktopAudioTrack: JitsiTrack
+ * }}
+ */
+export function setScreenshareAudioTrack(desktopAudioTrack) {
+    return {
+        type: SET_SCREENSHARE_TRACKS,
+        desktopAudioTrack
+    };
+}
+
 /**
  * Start the audio only screen sharing flow. Function will switch between off and on states depending on the context.
  *
@@ -65,6 +86,12 @@ export function startAudioScreenShareFlow() {
         // available for audio screen sharing, namely full window audio.
         // If we're already sharing audio, toggle off.
         if (shouldHideShareAudioHelper(state) || browser.isElectron() || audioOnlySharing) {
+            if (getMultipleVideoSupportFeatureFlag(state)) {
+                dispatch(toggleScreensharing(!audioOnlySharing, true));
+
+                return;
+            }
+
             // We don't want to explicity set the screens share state, by passing undefined we let the
             // underlying logic decide if it's on or off.
             dispatch(toggleScreensharing(undefined, true));
@@ -80,8 +107,7 @@ export function startAudioScreenShareFlow() {
  * Start normal screen sharing flow.Function will switch between off and on states depending on the context, and if
  * not explicity told otherwise.
  *
- * @param {boolean} enabled - Explicitly set the screen sharing state. This has been kept for backward compatibility
- * with the external API exposed by the iframe, even though it might not be used.
+ * @param {boolean} enabled - Explicitly set the screen sharing state.
  * @returns {void}
  */
 export function startScreenShareFlow(enabled: boolean) {

react/features/screen-share/functions.js

@@ -1,10 +1,11 @@
 // @flow
 
+import { getMultipleVideoSupportFeatureFlag } from '../base/config';
 import { isWindows } from '../base/environment';
 import { isMobileBrowser } from '../base/environment/utils';
 import { browser } from '../base/lib-jitsi-meet';
 import { VIDEO_TYPE } from '../base/media';
-import { getLocalVideoTrack } from '../base/tracks';
+import { getLocalDesktopTrack, getLocalVideoTrack } from '../base/tracks';
 
 /**
  * Is the current screen sharing session audio only.
@@ -53,7 +54,14 @@ export function isScreenMediaShared(state: Object) {
  * @returns {boolean}
  */
 export function isScreenVideoShared(state: Object) {
-    const localVideo = getLocalVideoTrack(state['features/base/tracks']);
+    const tracks = state['features/base/tracks'];
+    const localScreenshare = getLocalDesktopTrack(tracks);
+
+    if (getMultipleVideoSupportFeatureFlag(state)) {
+
+        return localScreenshare && localScreenshare.jitsiTrack && !localScreenshare.jitsiTrack.isMuted();
+    }
+    const localVideo = getLocalVideoTrack(tracks);
 
     // $FlowFixMe - No support for optional chain method calls in flow atm.
     return localVideo?.jitsiTrack?.getVideoType() === VIDEO_TYPE.DESKTOP;

react/features/screen-share/reducer.js

@@ -1,13 +1,17 @@
 
 import { ReducerRegistry } from '../base/redux';
 
-import { SET_SCREEN_AUDIO_SHARE_STATE, SET_SCREENSHARE_CAPTURE_FRAME_RATE } from './actionTypes';
+import {
+    SET_SCREEN_AUDIO_SHARE_STATE,
+    SET_SCREENSHARE_CAPTURE_FRAME_RATE,
+    SET_SCREENSHARE_TRACKS
+} from './actionTypes';
 
 /**
  * Reduces the Redux actions of the feature features/screen-share.
  */
 ReducerRegistry.register('features/screen-share', (state = {}, action) => {
-    const { captureFrameRate, isSharingAudio } = action;
+    const { captureFrameRate, isSharingAudio, desktopAudioTrack } = action;
 
     switch (action.type) {
     case SET_SCREEN_AUDIO_SHARE_STATE:
@@ -22,6 +26,12 @@ ReducerRegistry.register('features/screen-share', (state = {}, action) => {
             captureFrameRate
         };
 
+    case SET_SCREENSHARE_TRACKS:
+        return {
+            ...state,
+            desktopAudioTrack
+        };
+
     default:
         return state;
     }

react/features/toolbox/components/web/Toolbox.js

@@ -579,6 +579,7 @@ class Toolbox extends Component<Props> {
             _desktopSharingButtonDisabled,
             _desktopSharingEnabled,
             _localVideo,
+            _screenSharing,
             _virtualSource,
             dispatch
         } = this.props;
@@ -599,7 +600,7 @@ class Toolbox extends Component<Props> {
         }
 
         if (_desktopSharingEnabled && !_desktopSharingButtonDisabled) {
-            dispatch(startScreenShareFlow());
+            dispatch(startScreenShareFlow(!_screenSharing));
         }
     }