Add track selection mode based on selectionPriority attribute (#3751)

dsilhavy · web-flow · commit 5e31f9fb4cf7 · 2021-09-05T09:29:14.000+02:00
* Add track selection mode based on selectionPriority attribute in the manifest. Make this the default mode and fallback to TRACK_SELECTION_MODE_HIGHEST_BITRATE and TRACK_SELECTION_MODE_WIDEST_RANGE in case no selectionPriority is given.
diff --git a/index.d.ts b/index.d.ts
@@ -1475,7 +1475,7 @@ declare namespace dashjs {
 
     export type MetricType = 'ManifestUpdate' | 'RequestsQueue';
     export type TrackSwitchMode = 'alwaysReplace' | 'neverReplace';
-    export type TrackSelectionMode = 'highestBitrate' | 'firstTrack' | 'highestEfficiency' | 'widestRange';
+    export type TrackSelectionMode = 'highestSelectionPriority' | 'highestBitrate' | 'firstTrack' | 'highestEfficiency' | 'widestRange';
 
     export function supportsMediaSource(): boolean;
 
diff --git a/src/core/Settings.js b/src/core/Settings.js
@@ -142,7 +142,7 @@ import {HTTPRequest} from '../streaming/vo/metrics/HTTPRequest';
  *                audio: Constants.TRACK_SWITCH_MODE_ALWAYS_REPLACE,
  *                video: Constants.TRACK_SWITCH_MODE_NEVER_REPLACE
  *            },
- *            selectionModeForInitialTrack: Constants.TRACK_SELECTION_MODE_HIGHEST_BITRATE,
+ *            selectionModeForInitialTrack: Constants.TRACK_SELECTION_MODE_HIGHEST_SELECTION_PRIORITY,
  *            fragmentRequestTimeout: 0,
  *            retryIntervals: {
  *                [HTTPRequest.MPD_TYPE]: 500,
@@ -682,8 +682,11 @@ import {HTTPRequest} from '../streaming/vo/metrics/HTTPRequest';
  *
  * Possible values
  *
+ * - Constants.TRACK_SELECTION_MODE_HIGHEST_SELECTION_PRIORITY
+ * This mode makes the player select the track with the highest selectionPriority as defined in the manifest. If not selectionPriority is given we fallback to TRACK_SELECTION_MODE_HIGHEST_BITRATE. This mode is a default mode.
+ *
  * - Constants.TRACK_SELECTION_MODE_HIGHEST_BITRATE
- * This mode makes the player select the track with a highest bitrate. This mode is a default mode.
+ * This mode makes the player select the track with a highest bitrate.
  *
  * - Constants.TRACK_SELECTION_MODE_FIRST_TRACK
  * This mode makes the player select the first track found in the manifest.
@@ -825,7 +828,7 @@ function Settings() {
                 audio: Constants.TRACK_SWITCH_MODE_ALWAYS_REPLACE,
                 video: Constants.TRACK_SWITCH_MODE_NEVER_REPLACE
             },
-            selectionModeForInitialTrack: Constants.TRACK_SELECTION_MODE_HIGHEST_BITRATE,
+            selectionModeForInitialTrack: Constants.TRACK_SELECTION_MODE_HIGHEST_SELECTION_PRIORITY,
             fragmentRequestTimeout: 0,
             retryIntervals: {
                 [HTTPRequest.MPD_TYPE]: 500,
diff --git a/src/dash/DashAdapter.js b/src/dash/DashAdapter.js
@@ -1023,6 +1023,7 @@ function DashAdapter() {
         mediaInfo.mimeType = dashManifestModel.getMimeType(realAdaptation);
         mediaInfo.contentProtection = dashManifestModel.getContentProtectionData(realAdaptation);
         mediaInfo.bitrateList = dashManifestModel.getBitrateListForAdaptation(realAdaptation);
+        mediaInfo.selectionPriority = dashManifestModel.getSelectionPriority(realAdaptation);
 
         if (mediaInfo.contentProtection) {
             mediaInfo.contentProtection.forEach(function (item) {
diff --git a/src/dash/models/DashManifestModel.js b/src/dash/models/DashManifestModel.js
@@ -406,6 +406,16 @@ function DashManifestModel() {
         });
     }
 
+    function getSelectionPriority(realAdaption) {
+        try {
+            const priority = realAdaption && typeof realAdaption.selectionPriority !== 'undefined' ? parseInt(realAdaption.selectionPriority) : 1;
+
+            return isNaN(priority) ? 1 : priority;
+        } catch (e) {
+            return 1;
+        }
+    }
+
     function getEssentialPropertiesForRepresentation(realRepresentation) {
         if (!realRepresentation || !realRepresentation.EssentialProperty_asArray || !realRepresentation.EssentialProperty_asArray.length) return null;
 
@@ -1169,6 +1179,7 @@ function DashManifestModel() {
         getRealPeriods,
         getRealPeriodForIndex,
         getCodec,
+        getSelectionPriority,
         getMimeType,
         getKID,
         getLabelsForAdaptation,
diff --git a/src/dash/vo/MediaInfo.js b/src/dash/vo/MediaInfo.js
@@ -52,6 +52,7 @@ class MediaInfo {
         this.bitrateList = null;
         this.isFragmented = null;
         this.isEmbedded = null;
+        this.selectionPriority = 1;
     }
 
 }
diff --git a/src/streaming/constants/Constants.js b/src/streaming/constants/Constants.js
@@ -248,6 +248,13 @@ class Constants {
          */
         this.TRACK_SELECTION_MODE_WIDEST_RANGE = 'widestRange';
 
+        /**
+         *  @constant {string} TRACK_SELECTION_MODE_WIDEST_RANGE makes the player select the track with the highest selectionPriority as defined in the manifest
+         *  @memberof Constants#
+         *  @static
+         */
+        this.TRACK_SELECTION_MODE_HIGHEST_SELECTION_PRIORITY = 'highestSelectionPriority';
+
         /**
          *  @constant {string} CMCD_MODE_QUERY specifies to attach CMCD metrics as query parameters.
          *  @memberof Constants#
diff --git a/src/streaming/controllers/MediaController.js b/src/streaming/controllers/MediaController.js
@@ -330,6 +330,28 @@ function MediaController() {
         };
     }
 
+    function getTracksWithHighestSelectionPriority(trackArr) {
+        let max = 0;
+        let result = [];
+
+        trackArr.forEach((track) => {
+            if(!isNaN(track.selectionPriority)) {
+                // Higher max value. Reset list and add new entry
+                if (track.selectionPriority > max) {
+                    max = track.selectionPriority;
+                    result = [track];
+                }
+                // Same max value add to list
+                else if (track.selectionPriority === max) {
+                    result.push(track);
+                }
+
+            }
+        })
+
+        return result;
+    }
+
     function getTracksWithHighestBitrate(trackArr) {
         let max = 0;
         let result = [];
@@ -402,45 +424,87 @@ function MediaController() {
         if (type === Constants.TEXT) return tracks[0];
 
         let mode = settings.get().streaming.selectionModeForInitialTrack;
-        let tmpArr = [];
+        let tmpArr;
 
         if (customInitialTrackSelectionFunction && typeof customInitialTrackSelectionFunction === 'function') {
             tmpArr = customInitialTrackSelectionFunction(tracks);
         } else {
             switch (mode) {
+                case Constants.TRACK_SELECTION_MODE_HIGHEST_SELECTION_PRIORITY:
+                    tmpArr = _trackSelectionModeHighestSelectionPriority(tracks);
+                    break;
                 case Constants.TRACK_SELECTION_MODE_HIGHEST_BITRATE:
-                    tmpArr = getTracksWithHighestBitrate(tracks);
-
-                    if (tmpArr.length > 1) {
-                        tmpArr = getTracksWithWidestRange(tmpArr);
-                    }
+                    tmpArr = _trackSelectionModeHighestBitrate(tracks);
                     break;
                 case Constants.TRACK_SELECTION_MODE_FIRST_TRACK:
-                    tmpArr.push(tracks[0]);
+                    tmpArr = _trackSelectionModeFirstTrack(tracks);
                     break;
                 case Constants.TRACK_SELECTION_MODE_HIGHEST_EFFICIENCY:
-                    tmpArr = getTracksWithHighestEfficiency(tracks);
-
-                    if (tmpArr.length > 1) {
-                        tmpArr = getTracksWithHighestBitrate(tmpArr);
-                    }
+                    tmpArr = _trackSelectionModeHighestEfficiency(tracks);
                     break;
                 case Constants.TRACK_SELECTION_MODE_WIDEST_RANGE:
-                    tmpArr = getTracksWithWidestRange(tracks);
-
-                    if (tmpArr.length > 1) {
-                        tmpArr = getTracksWithHighestBitrate(tracks);
-                    }
+                    tmpArr = _trackSelectionModeWidestRange(tracks);
                     break;
                 default:
-                    logger.warn('Track selection mode is not supported: ' + mode);
+                    logger.warn(`Track selection mode ${mode} is not supported. Falling back to TRACK_SELECTION_MODE_FIRST_TRACK`);
+                    tmpArr = _trackSelectionModeFirstTrack(tracks);
                     break;
             }
         }
 
-        return tmpArr[0];
+        return tmpArr.length > 0 ? tmpArr[0] : tracks[0];
     }
 
+
+    function _trackSelectionModeHighestSelectionPriority(tracks) {
+        let tmpArr = getTracksWithHighestSelectionPriority(tracks);
+
+        if (tmpArr.length > 1) {
+            tmpArr = getTracksWithHighestBitrate(tmpArr);
+        }
+
+        if (tmpArr.length > 1) {
+            tmpArr = getTracksWithWidestRange(tmpArr);
+        }
+
+        return tmpArr;
+    }
+
+    function _trackSelectionModeHighestBitrate(tracks) {
+        let tmpArr = getTracksWithHighestBitrate(tracks);
+
+        if (tmpArr.length > 1) {
+            tmpArr = getTracksWithWidestRange(tmpArr);
+        }
+
+        return tmpArr;
+    }
+
+    function _trackSelectionModeFirstTrack(tracks) {
+        return tracks[0];
+    }
+
+    function _trackSelectionModeHighestEfficiency(tracks) {
+        let tmpArr = getTracksWithHighestEfficiency(tracks);
+
+        if (tmpArr.length > 1) {
+            tmpArr = getTracksWithHighestBitrate(tmpArr);
+        }
+
+        return tmpArr;
+    }
+
+    function _trackSelectionModeWidestRange(tracks) {
+        let tmpArr = getTracksWithWidestRange(tracks);
+
+        if (tmpArr.length > 1) {
+            tmpArr = getTracksWithHighestBitrate(tracks);
+        }
+
+        return tmpArr;
+    }
+
+
     function createTrackInfo() {
         return {
             audio: {
diff --git a/test/unit/dash.models.DashManifestModel.js b/test/unit/dash.models.DashManifestModel.js
diff --git a/test/unit/streaming.controllers.MediaController.js b/test/unit/streaming.controllers.MediaController.js

Original file line number	Diff line number	Diff line change
`@@ -52,6 +52,7 @@ class MediaInfo {`
`52`	`52`	`this.bitrateList = null;`
`53`	`53`	`this.isFragmented = null;`
`54`	`54`	`this.isEmbedded = null;`
	`55`	`+ this.selectionPriority = 1;`
`55`	`56`	`}`
`56`	`57`
`57`	`58`	`}`