Source: lib/polyfill/videoplaybackquality.js

  1. /*! @license
  2.  * Shaka Player
  3.  * Copyright 2016 Google LLC
  4.  * SPDX-License-Identifier: Apache-2.0
  5.  */
  7. goog.provide('shaka.polyfill.VideoPlaybackQuality');
  9. goog.require('shaka.polyfill');
  10. goog.require('shaka.util.Dom');
  13. /**
  14.  * @summary A polyfill to provide MSE VideoPlaybackQuality metrics.
  15.  * Many browsers do not yet provide this API, and Chrome currently provides
  16.  * similar data through individual prefixed attributes on HTMLVideoElement.
  17.  * @export
  18.  */
  19. shaka.polyfill.VideoPlaybackQuality = class {
  20.   /**
  21.    * Install the polyfill if needed.
  22.    * @export
  23.    */
  24.   static install() {
  25.     if (!window.HTMLVideoElement) {
  26.       // Avoid errors on very old browsers.
  27.       return;
  28.     }
  30.     // eslint-disable-next-line no-restricted-syntax
  31.     const proto = HTMLVideoElement.prototype;
  32.     if (proto.getVideoPlaybackQuality) {
  33.       // No polyfill needed.
  34.       return;
  35.     }
  37.     if ('webkitDroppedFrameCount' in proto ||
  38.         typeof shaka.util.Dom.anyMediaElement().webkitDroppedFrameCount ===
  39.           'number') {
  40.       proto.getVideoPlaybackQuality =
  41.           shaka.polyfill.VideoPlaybackQuality.webkit_;
  42.     }
  43.   }
  45.   /**
  46.    * @this {HTMLVideoElement}
  47.    * @return {!VideoPlaybackQuality}
  48.    * @private
  49.    */
  50.   static webkit_() {
  51.     return {
  52.       'droppedVideoFrames': this.webkitDroppedFrameCount,
  53.       'totalVideoFrames': this.webkitDecodedFrameCount,
  54.       // Not provided by this polyfill:
  55.       'corruptedVideoFrames': 0,
  56.       'creationTime': NaN,
  57.       'totalFrameDelay': 0,
  58.     };
  59.   }
  60. };
  63. shaka.polyfill.register(shaka.polyfill.VideoPlaybackQuality.install);