Enable/Disable UTC sync via settings flag (#3802)

Author: dsilhavy

index.d.ts

@@ -201,6 +201,7 @@ declare namespace dashjs {
                 enableSeekFix?: boolean
             },
             utcSynchronization?: {
+                enabled?: boolean,
                 useManifestDateHeaderTimeSource?: boolean,
                 backgroundAttempts?: number,
                 timeBetweenSyncAttempts?: number,

src/core/Settings.js

@@ -108,6 +108,7 @@ import {HTTPRequest} from '../streaming/vo/metrics/HTTPRequest';
  *                enableSeekFix: false
  *            },
  *            utcSynchronization: {
+ *                enabled: true,
  *                useManifestDateHeaderTimeSource: true,
  *                backgroundAttempts: 2,
  *                timeBetweenSyncAttempts: 30,
@@ -378,7 +379,8 @@ import {HTTPRequest} from '../streaming/vo/metrics/HTTPRequest';
 
 /**
  * @typedef {Object} UtcSynchronizationSettings
- *
+ * @property {boolean} [enabled=true]
+ * Enables or disables the UTC clock synchronization
  * @property {boolean} [useManifestDateHeaderTimeSource=true]
  * Allows you to enable the use of the Date Header, if exposed with CORS, as a timing source for live edge detection.
  *
@@ -802,6 +804,7 @@ function Settings() {
                 enableSeekFix: false
             },
             utcSynchronization: {
+                enabled: true,
                 useManifestDateHeaderTimeSource: true,
                 backgroundAttempts: 2,
                 timeBetweenSyncAttempts: 30,

src/streaming/controllers/TimeSyncController.js

@@ -168,7 +168,7 @@ function TimeSyncController() {
      * Does a synchronization in the background in case the last offset should be verified or a 404 occurs
      */
     function _onAttemptBackgroundSync() {
-        if (isSynchronizing || isBackgroundSynchronizing || !lastTimingSource || !lastTimingSource.value || !lastTimingSource.schemeIdUri || isNaN(lastOffset) || isNaN(settings.get().streaming.utcSynchronization.backgroundAttempts)) {
+        if (!settings.get().streaming.utcSynchronization.enabled || isSynchronizing || isBackgroundSynchronizing || !lastTimingSource || !lastTimingSource.value || !lastTimingSource.schemeIdUri || isNaN(lastOffset) || isNaN(settings.get().streaming.utcSynchronization.backgroundAttempts)) {
             return;
         }
 
@@ -287,7 +287,7 @@ function TimeSyncController() {
      */
     function _shouldPerformSynchronization(isDynamic) {
         try {
-            if (!isDynamic) {
+            if (!isDynamic || !settings.get().streaming.utcSynchronization.enabled) {
                 return false;
             }
             const timeBetweenSyncAttempts = !isNaN(internalTimeBetweenSyncAttempts) ? internalTimeBetweenSyncAttempts : DEFAULT_TIME_BETWEEN_SYNC_ATTEMPTS;