feat: Handle audio focus events (#8427)

In some platforms custom audio focus events are emitted. This needs to
be handled to avoid the stall detection.

---------

Co-authored-by: Srikanth Peddibhotla <[email protected]>
Co-authored-by: Álvaro Velad Galván <[email protected]>

Author: 3 people

lib/media/gap_jumping_controller.js

@@ -394,6 +394,9 @@ shaka.media.StallDetector = class {
   /** @override */
   release() {
     // Drop external references to make things easier on the GC.
+    if (this.implementation_) {
+      this.implementation_.release();
+    }
     this.implementation_ = null;
     this.onStall_ = null;
   }
@@ -465,6 +468,11 @@ shaka.media.StallDetector.Implementation = class {
    * @return {number}
    */
   getWallSeconds() {}
+
+  /**
+   * Releases object
+   */
+  release() {}
 };
 
 
@@ -482,6 +490,34 @@ shaka.media.StallDetector.MediaElementImplementation = class {
   constructor(mediaElement) {
     /** @private {!HTMLMediaElement} */
     this.mediaElement_ = mediaElement;
+    /**
+     * For listeners scoped to the lifetime of the instance.
+     * @private {shaka.util.EventManager}
+     */
+    this.audioEventManager_ = new shaka.util.EventManager();
+    /**
+     * Audio focus state
+     * @private {boolean}
+     */
+    this.audioFocusPaused_ = false;
+    // Audio Focus temporary leads to playback pause.
+    this.audioEventManager_.listen(this.mediaElement_,
+        'audiofocuspaused', () => {
+          shaka.log.info(`Audio focus paused`);
+          this.audioFocusPaused_ = true;
+        });
+    // Audio Focus is granted. App can play now.
+    this.audioEventManager_.listen(this.mediaElement_,
+        'audiofocusgranted', () => {
+          shaka.log.info(`Audio focus granted`);
+          this.audioFocusPaused_ = false;
+        });
+    // Audio focus is lost, app shouldn't play anymore.
+    this.audioEventManager_.listen(this.mediaElement_,
+        'audiofocuslost', () => {
+          shaka.log.info(`Audio focus lost`);
+          this.audioFocusPaused_ = true;
+        });
   }
 
   /** @override */
@@ -494,7 +530,10 @@ shaka.media.StallDetector.MediaElementImplementation = class {
     if (this.mediaElement_.playbackRate == 0) {
       return false;
     }
-
+    // If playback paused due to no audio focus, we ignore the stall.
+    if (this.audioFocusPaused_) {
+      return false;
+    }
     // If we have don't have enough content, we are not stalled, we are
     // buffering.
     if (this.mediaElement_.buffered.length == 0) {
@@ -542,5 +581,13 @@ shaka.media.StallDetector.MediaElementImplementation = class {
 
     return false;
   }
+
+  /** @override */
+  release() {
+    if (this.audioEventManager_) {
+      this.audioEventManager_.release();
+    }
+    this.audioEventManager_ = null;
+  }
 };
 

project-words.txt

@@ -1,6 +1,9 @@
 # events / html
 abrstatuschanged
 adblocker
+audiofocuspaused
+audiofocusgranted
+audiofocuslost
 audiolang
 audiotrackchange
 audiotrackchanged

test/media/stall_detector_unit.js

@@ -29,6 +29,9 @@ describe('StallDetector', () => {
 
     /** @override */
     getWallSeconds() { return this.wallSeconds; }
+
+    /** @override */
+    release() {}
   }
 
   /** @type {!TestImplementation} */