feat: Support frequent updates during streaming (#3483)

Close: #3332

Author: Álvaro Velad Galván

demo/common/message_ids.js

@@ -235,6 +235,7 @@ shakaDemo.MessageIds = {
   TRICK_PLAY_CONTROLS_WARNING: 'DEMO_TRICK_PLAY_CONTROLS_WARNING',
   UI_LOCALE: 'DEMO_UI_LOCALE',
   UPDATE_EXPIRATION_TIME: 'DEMO_UPDATE_EXPIRATION_TIME',
+  UPDATE_INTERVAL_SECONDS: 'DEMO_UPDATE_INTERVAL_SECONDS',
   USE_NATIVE_HLS_SAFARI: 'DEMO_USE_NATIVE_HLS_SAFARI',
   USE_PERSISTENT_LICENSES: 'DEMO_USE_PERSISTENT_LICENSES',
   VIDEO_ROBUSTNESS: 'DEMO_VIDEO_ROBUSTNESS',

demo/config.js

@@ -359,7 +359,10 @@ shakaDemo.Config = class {
         .addBoolInput_(MessageIds.FORCE_HTTPS,
             'streaming.forceHTTPS')
         .addBoolInput_(MessageIds.PREFER_NATIVE_HLS,
-            'streaming.preferNativeHls');
+            'streaming.preferNativeHls')
+        .addNumberInput_(MessageIds.UPDATE_INTERVAL_SECONDS,
+            'streaming.updateIntervalSeconds',
+            /* canBeDecimal= */ true);
 
     if (!shakaDemoMain.getNativeControlsEnabled()) {
       this.addBoolInput_(MessageIds.ALWAYS_STREAM_TEXT,

demo/locales/en.json

@@ -208,6 +208,7 @@
   "DEMO_UNSUPPORTED_NO_LICENSE_SUPPORT": "Your browser does not support offline licenses for the required key systems.",
   "DEMO_UNSUPPORTED_NO_OFFLINE": "Your browser does not support offline storage.",
   "DEMO_UPDATE_EXPIRATION_TIME": "Update expiration time",
+  "DEMO_UPDATE_INTERVAL_SECONDS": "Update interval seconds",
   "DEMO_UPLYNK": "Verizon Digital Media Services",
   "DEMO_USE_FULL_SEGMENTS_FOR_START_TIME": "Use Full Segments For Start Time",
   "DEMO_USE_NATIVE_HLS_SAFARI": "Use native HLS on Safari",

demo/locales/source.json

@@ -839,6 +839,10 @@
     "description": "The name of a configuration value.",
     "message": "Update expiration time"
   },
+  "DEMO_UPDATE_INTERVAL_SECONDS": {
+    "description": "The name of a configuration value.",
+    "message": "Update interval seconds"
+  },
   "DEMO_UPLYNK": {
     "description": "Text that describes an asset that comes from the Verizon Digital Media Services asset library.",
     "message": "[PROPER_NAME:Verizon Digital Media Services]"

externs/shaka/player.js

@@ -789,7 +789,8 @@ shaka.extern.ManifestConfiguration;
  *   lowLatencyMode: boolean,
  *   autoLowLatencyMode: boolean,
  *   forceHTTPS: boolean,
- *   preferNativeHls: boolean
+ *   preferNativeHls: boolean,
+ *   updateIntervalSeconds: number
  * }}
  *
  * @description
@@ -896,6 +897,8 @@ shaka.extern.ManifestConfiguration;
  *   If true, if the protocol is HTTP change it to HTTPs.
  * @property {boolean} preferNativeHls
  *   If true, prefer native HLS playback when possible, regardless of platform.
+ * @property {number} updateIntervalSeconds
+ *   The minimum number of seconds to see if the manifest has changes.
  *
  * @exportDoc
  */

lib/media/streaming_engine.js

@@ -1001,10 +1001,10 @@ shaka.media.StreamingEngine = class {
     if (bufferedAhead >= scaledBufferingGoal) {
       shaka.log.v2(logPrefix, 'buffering goal met');
 
-      // Do not try to predict the next update.  Just poll twice every second.
-      // The playback rate can change at any time, so any prediction we make now
-      // could be terribly invalid soon.
-      return 0.5;
+      // Do not try to predict the next update.  Just poll according to
+      // configuration (seconds). The playback rate can change at any time, so
+      // any prediction we make now could be terribly invalid soon.
+      return this.config_.updateIntervalSeconds / 2;
     }
 
     const bufferEnd =
@@ -1016,7 +1016,7 @@ shaka.media.StreamingEngine = class {
       // In any case just try again... if the manifest is incomplete or is not
       // being updated then we'll idle forever; otherwise, we'll end up getting
       // a SegmentReference eventually.
-      return 1;
+      return this.config_.updateIntervalSeconds;
     }
 
     // Do not let any one stream get far ahead of any other.
@@ -1047,7 +1047,7 @@ shaka.media.StreamingEngine = class {
       // For example, let video buffering catch up to audio buffering before
       // fetching another audio segment.
       shaka.log.v2(logPrefix, 'waiting for other streams to buffer');
-      return 1;
+      return this.config_.updateIntervalSeconds;
     }
 
     const p = this.fetchAndAppend_(mediaState, presentationTime, reference);

lib/util/player_configuration.js

@@ -162,6 +162,7 @@ shaka.util.PlayerConfiguration = class {
       autoLowLatencyMode: false,
       forceHTTPS: false,
       preferNativeHls: false,
+      updateIntervalSeconds: 1,
     };
 
     // Some browsers will stop earlier than others before a gap (e.g., Edge