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');
  12. /**
  13.  * @summary A polyfill to provide MSE VideoPlaybackQuality metrics.
  14.  * Many browsers do not yet provide this API, and Chrome currently provides
  15.  * similar data through individual prefixed attributes on HTMLVideoElement.
  16.  * @export
  17.  */
  18. shaka.polyfill.VideoPlaybackQuality = class {
  19.   /**
  20.    * Install the polyfill if needed.
  21.    * @export
  22.    */
  23.   static install() {
  24.     if (!window.HTMLVideoElement) {
  25.       // Avoid errors on very old browsers.
  26.       return;
  27.     }
  29.     // eslint-disable-next-line no-restricted-syntax
  30.     const proto = HTMLVideoElement.prototype;
  31.     if (proto.getVideoPlaybackQuality) {
  32.       // No polyfill needed.
  33.       return;
  34.     }
  36.     if ('webkitDroppedFrameCount' in proto) {
  37.       proto.getVideoPlaybackQuality =
  38.           shaka.polyfill.VideoPlaybackQuality.webkit_;
  39.     }
  40.   }
  42.   /**
  43.    * @this {HTMLVideoElement}
  44.    * @return {!VideoPlaybackQuality}
  45.    * @private
  46.    */
  47.   static webkit_() {
  48.     return {
  49.       'droppedVideoFrames': this.webkitDroppedFrameCount,
  50.       'totalVideoFrames': this.webkitDecodedFrameCount,
  51.       // Not provided by this polyfill:
  52.       'corruptedVideoFrames': 0,
  53.       'creationTime': NaN,
  54.       'totalFrameDelay': 0,
  55.     };
  56.   }
  57. };
  60. shaka.polyfill.register(shaka.polyfill.VideoPlaybackQuality.install);