Source: lib/util/platform.js

  1. /*! @license
  2.  * Shaka Player
  3.  * Copyright 2016 Google LLC
  4.  * SPDX-License-Identifier: Apache-2.0
  5.  */
  7. goog.provide('shaka.util.Platform');
  9. goog.require('shaka.drm.DrmUtils');
  10. goog.require('shaka.log');
  11. goog.require('shaka.util.Timer');
  14. /**
  15.  * A wrapper for platform-specific functions.
  16.  *
  17.  * @final
  18.  */
  19. shaka.util.Platform = class {
  20.   /**
  21.    * Check if the current platform supports media source. We assume that if
  22.    * the current platform supports media source, then we can use media source
  23.    * as per its design.
  24.    *
  25.    * @return {boolean}
  26.    */
  27.   static supportsMediaSource() {
  28.     const mediaSource = window.ManagedMediaSource || window.MediaSource;
  29.     // Browsers that lack a media source implementation will have no reference
  30.     // to |window.MediaSource|. Platforms that we see having problematic media
  31.     // source implementations will have this reference removed via a polyfill.
  32.     if (!mediaSource) {
  33.       return false;
  34.     }
  36.     // Some very old MediaSource implementations didn't have isTypeSupported.
  37.     if (!mediaSource.isTypeSupported) {
  38.       return false;
  39.     }
  41.     return true;
  42.   }
  44.   /**
  45.    * Returns true if the media type is supported natively by the platform.
  46.    *
  47.    * @param {string} mimeType
  48.    * @return {boolean}
  49.    */
  50.   static supportsMediaType(mimeType) {
  51.     const video = shaka.util.Platform.anyMediaElement();
  52.     return video.canPlayType(mimeType) != '';
  53.   }
  55.   /**
  56.    * Check if the current platform is MS Edge.
  57.    *
  58.    * @return {boolean}
  59.    */
  60.   static isEdge() {
  61.     // Legacy Edge contains "Edge/version".
  62.     // Chromium-based Edge contains "Edg/version" (no "e").
  63.     if (navigator.userAgent.match(/Edge?\//)) {
  64.       return true;
  65.     }
  67.     return false;
  68.   }
  70.   /**
  71.    * Check if the current platform is Legacy Edge.
  72.    *
  73.    * @return {boolean}
  74.    */
  75.   static isLegacyEdge() {
  76.     // Legacy Edge contains "Edge/version".
  77.     // Chromium-based Edge contains "Edg/version" (no "e").
  78.     if (navigator.userAgent.match(/Edge\//)) {
  79.       return true;
  80.     }
  82.     return false;
  83.   }
  85.   /**
  86.    * Check if the current platform is MS IE.
  87.    *
  88.    * @return {boolean}
  89.    */
  90.   static isIE() {
  91.     return shaka.util.Platform.userAgentContains_('Trident/');
  92.   }
  94.   /**
  95.    * Check if the current platform is an Xbox One.
  96.    *
  97.    * @return {boolean}
  98.    */
  99.   static isXboxOne() {
  100.     return shaka.util.Platform.userAgentContains_('Xbox One');
  101.   }
  103.   /**
  104.    * Check if the current platform is a Tizen TV.
  105.    *
  106.    * @return {boolean}
  107.    */
  108.   static isTizen() {
  109.     return shaka.util.Platform.userAgentContains_('Tizen');
  110.   }
  112.   /**
  113.    * Check if the current platform is a Tizen 6 TV.
  114.    *
  115.    * @return {boolean}
  116.    */
  117.   static isTizen6() {
  118.     return shaka.util.Platform.userAgentContains_('Tizen 6');
  119.   }
  121.   /**
  122.    * Check if the current platform is a Tizen 5.0 TV.
  123.    *
  124.    * @return {boolean}
  125.    */
  126.   static isTizen5_0() {
  127.     return shaka.util.Platform.userAgentContains_('Tizen 5.0');
  128.   }
  130.   /**
  131.    * Check if the current platform is a Tizen 5 TV.
  132.    *
  133.    * @return {boolean}
  134.    */
  135.   static isTizen5() {
  136.     return shaka.util.Platform.userAgentContains_('Tizen 5');
  137.   }
  139.   /**
  140.    * Check if the current platform is a Tizen 4 TV.
  141.    *
  142.    * @return {boolean}
  143.    */
  144.   static isTizen4() {
  145.     return shaka.util.Platform.userAgentContains_('Tizen 4');
  146.   }
  148.   /**
  149.    * Check if the current platform is a Tizen 3 TV.
  150.    *
  151.    * @return {boolean}
  152.    */
  153.   static isTizen3() {
  154.     return shaka.util.Platform.userAgentContains_('Tizen 3');
  155.   }
  157.   /**
  158.    * Check if the current platform is a Tizen 2 TV.
  159.    *
  160.    * @return {boolean}
  161.    */
  162.   static isTizen2() {
  163.     return shaka.util.Platform.userAgentContains_('Tizen 2');
  164.   }
  166.   /**
  167.    * Check if the current platform is a WebOS.
  168.    *
  169.    * @return {boolean}
  170.    */
  171.   static isWebOS() {
  172.     return shaka.util.Platform.userAgentContains_('Web0S');
  173.   }
  175.   /**
  176.    * Check if the current platform is a WebOS 3.
  177.    *
  178.    * @return {boolean}
  179.    */
  180.   static isWebOS3() {
  181.     // See: https://webostv.developer.lge.com/develop/specifications/web-api-and-web-engine#useragent-string
  182.     return shaka.util.Platform.isWebOS() &&
  183.         shaka.util.Platform.chromeVersion() === 38;
  184.   }
  186.   /**
  187.    * Check if the current platform is a WebOS 4.
  188.    *
  189.    * @return {boolean}
  190.    */
  191.   static isWebOS4() {
  192.     // See: https://webostv.developer.lge.com/develop/specifications/web-api-and-web-engine#useragent-string
  193.     return shaka.util.Platform.isWebOS() &&
  194.         shaka.util.Platform.chromeVersion() === 53;
  195.   }
  197.   /**
  198.    * Check if the current platform is a WebOS 5.
  199.    *
  200.    * @return {boolean}
  201.    */
  202.   static isWebOS5() {
  203.     // See: https://webostv.developer.lge.com/develop/specifications/web-api-and-web-engine#useragent-string
  204.     return shaka.util.Platform.isWebOS() &&
  205.         shaka.util.Platform.chromeVersion() === 68;
  206.   }
  208.   /**
  209.    * Check if the current platform is a WebOS 6.
  210.    *
  211.    * @return {boolean}
  212.    */
  213.   static isWebOS6() {
  214.     // See: https://webostv.developer.lge.com/develop/specifications/web-api-and-web-engine#useragent-string
  215.     return shaka.util.Platform.isWebOS() &&
  216.         shaka.util.Platform.chromeVersion() === 79;
  217.   }
  219.   /**
  220.    * Check if the current platform is a Google Chromecast.
  221.    *
  222.    * @return {boolean}
  223.    */
  224.   static isChromecast() {
  225.     return shaka.util.Platform.userAgentContains_('CrKey');
  226.   }
  228.   /**
  229.    * Check if the current platform is a Google Chromecast without
  230.    * Android or Fuchsia.
  231.    *
  232.    * @return {boolean}
  233.    */
  234.   static isOlderChromecast() {
  235.     const Platform = shaka.util.Platform;
  236.     return Platform.isChromecast() &&
  237.         !Platform.isAndroid() && !Platform.isFuchsia();
  238.   }
  240.   /**
  241.    * Check if the current platform is a Google Chromecast with Android
  242.    * (i.e. Chromecast with GoogleTV).
  243.    *
  244.    * @return {boolean}
  245.    */
  246.   static isAndroidCastDevice() {
  247.     const Platform = shaka.util.Platform;
  248.     return Platform.isChromecast() && Platform.isAndroid();
  249.   }
  251.   /**
  252.    * Check if the current platform is a Google Chromecast with Fuchsia
  253.    * (i.e. Google Nest Hub).
  254.    *
  255.    * @return {boolean}
  256.    */
  257.   static isFuchsiaCastDevice() {
  258.     const Platform = shaka.util.Platform;
  259.     return Platform.isChromecast() && Platform.isFuchsia();
  260.   }
  262.   /**
  263.    * Returns a major version number for Chrome, or Chromium-based browsers.
  264.    *
  265.    * For example:
  266.    *   - Chrome 106.0.5249.61 returns 106.
  267.    *   - Edge 106.0.1370.34 returns 106 (since this is based on Chromium).
  268.    *   - Safari returns null (since this is independent of Chromium).
  269.    *
  270.    * @return {?number} A major version number or null if not Chromium-based.
  271.    */
  272.   static chromeVersion() {
  273.     if (!shaka.util.Platform.isChrome()) {
  274.       return null;
  275.     }
  277.     // Looking for something like "Chrome/106.0.0.0".
  278.     const match = navigator.userAgent.match(/Chrome\/(\d+)/);
  279.     if (match) {
  280.       return parseInt(match[1], /* base= */ 10);
  281.     }
  283.     return null;
  284.   }
  286.   /**
  287.    * Check if the current platform is Google Chrome.
  288.    *
  289.    * @return {boolean}
  290.    */
  291.   static isChrome() {
  292.     // The Edge Legacy user agent will also contain the "Chrome" keyword, so we
  293.     // need to make sure this is not Edge Legacy.
  294.     return shaka.util.Platform.userAgentContains_('Chrome') &&
  295.            !shaka.util.Platform.isLegacyEdge();
  296.   }
  298.   /**
  299.    * Check if the current platform is Firefox.
  300.    *
  301.    * @return {boolean}
  302.    */
  303.   static isFirefox() {
  304.     return shaka.util.Platform.userAgentContains_('Firefox');
  305.   }
  307.   /**
  308.    * Check if the current platform is from Apple.
  309.    *
  310.    * Returns true on all iOS browsers and on desktop Safari.
  311.    *
  312.    * Returns false for non-Safari browsers on macOS, which are independent of
  313.    * Apple.
  314.    *
  315.    * @return {boolean}
  316.    */
  317.   static isApple() {
  318.     return shaka.util.Platform.isAppleVendor_() &&
  319.         (shaka.util.Platform.isMac() || shaka.util.Platform.isIOS());
  320.   }
  322.   /**
  323.    * Check if the current platform is Playstation 5.
  324.    *
  325.    * Returns true on Playstation 5 browsers.
  326.    *
  327.    * Returns false for Playstation 5 browsers
  328.    *
  329.    * @return {boolean}
  330.    */
  331.   static isPS5() {
  332.     return shaka.util.Platform.userAgentContains_('PlayStation 5');
  333.   }
  335.   /**
  336.    * Check if the current platform is Playstation 4.
  337.    * @return {boolean}
  338.    */
  339.   static isPS4() {
  340.     return shaka.util.Platform.userAgentContains_('PlayStation 4');
  341.   }
  343.   /**
  344.    * Check if the current platform is Hisense.
  345.    * @return {boolean}
  346.    */
  347.   static isHisense() {
  348.     return shaka.util.Platform.userAgentContains_('Hisense') ||
  349.         shaka.util.Platform.userAgentContains_('VIDAA');
  350.   }
  352.   /**
  353.    * Check if the current platform is Orange.
  354.    * @return {boolean}
  355.    */
  356.   static isOrange() {
  357.     return shaka.util.Platform.userAgentContains_('SOPOpenBrowser');
  358.   }
  360.   /**
  361.    * Check if the current platform is SkyQ STB.
  362.    * @return {boolean}
  363.    */
  364.   static isSkyQ() {
  365.     return shaka.util.Platform.userAgentContains_('Sky_STB');
  366.   }
  368.   /**
  369.    * Check if the current platform is Deutsche Telecom Zenterio STB.
  370.    * @return {boolean}
  371.    */
  372.   static isZenterio() {
  373.     return shaka.util.Platform.userAgentContains_('DT_STB_BCM');
  374.   }
  376.   /**
  377.    * Returns a major version number for Safari, or Webkit-based STBs,
  378.    * or Safari-based iOS browsers.
  379.    *
  380.    * For example:
  381.    *   - Safari 13.0.4 on macOS returns 13.
  382.    *   - Safari on iOS 13.3.1 returns 13.
  383.    *   - Chrome on iOS 13.3.1 returns 13 (since this is based on Safari/WebKit).
  384.    *   - Chrome on macOS returns null (since this is independent of Apple).
  385.    *
  386.    * Returns null on Firefox on iOS, where this version information is not
  387.    * available.
  388.    *
  389.    * @return {?number} A major version number or null if not iOS.
  390.    */
  391.   static safariVersion() {
  392.     // All iOS browsers and desktop Safari will return true for isApple().
  393.     if (!shaka.util.Platform.isApple() && !shaka.util.Platform.isWebkitSTB()) {
  394.       return null;
  395.     }
  397.     // This works for iOS Safari and desktop Safari, which contain something
  398.     // like "Version/13.0" indicating the major Safari or iOS version.
  399.     let match = navigator.userAgent.match(/Version\/(\d+)/);
  400.     if (match) {
  401.       return parseInt(match[1], /* base= */ 10);
  402.     }
  404.     // This works for all other browsers on iOS, which contain something like
  405.     // "OS 13_3" indicating the major & minor iOS version.
  406.     match = navigator.userAgent.match(/OS (\d+)(?:_\d+)?/);
  407.     if (match) {
  408.       return parseInt(match[1], /* base= */ 10);
  409.     }
  411.     return null;
  412.   }
  414.   /**
  415.    * Guesses if the platform is an Apple mobile one (iOS, iPad, iPod).
  416.    * @return {boolean}
  417.    */
  418.   static isIOS() {
  419.     if (/(?:iPhone|iPad|iPod)/.test(navigator.userAgent)) {
  420.       // This is Android, iOS, or iPad < 13.
  421.       return true;
  422.     }
  424.     // Starting with iOS 13 on iPad, the user agent string no longer has the
  425.     // word "iPad" in it.  It looks very similar to desktop Safari.  This seems
  426.     // to be intentional on Apple's part.
  427.     // See: https://forums.developer.apple.com/thread/119186
  428.     //
  429.     // So if it's an Apple device with multi-touch support, assume it's a mobile
  430.     // device.  If some future iOS version starts masking their user agent on
  431.     // both iPhone & iPad, this clause should still work.  If a future
  432.     // multi-touch desktop Mac is released, this will need some adjustment.
  433.     //
  434.     // As of January 2020, this is mainly used to adjust the default UI config
  435.     // for mobile devices, so it's low risk if something changes to break this
  436.     // detection.
  437.     return shaka.util.Platform.isAppleVendor_() && navigator.maxTouchPoints > 1;
  438.   }
  440.   /**
  441.    * Guesses if the platform is a mobile one.
  442.    * @return {boolean}
  443.    */
  444.   static isMobile() {
  445.     if (navigator.userAgentData) {
  446.       return navigator.userAgentData.mobile;
  447.     }
  448.     return shaka.util.Platform.isIOS() || shaka.util.Platform.isAndroid();
  449.   }
  451.   /**
  452.    * Return true if the platform is a Mac, regardless of the browser.
  453.    *
  454.    * @return {boolean}
  455.    */
  456.   static isMac() {
  457.     // Try the newer standard first.
  458.     if (navigator.userAgentData && navigator.userAgentData.platform) {
  459.       return navigator.userAgentData.platform.toLowerCase() == 'macos';
  460.     }
  461.     // Fall back to the old API, with less strict matching.
  462.     if (!navigator.platform) {
  463.       return false;
  464.     }
  465.     return navigator.platform.toLowerCase().includes('mac');
  466.   }
  468.   /**
  469.    * Return true if the platform is a VisionOS.
  470.    *
  471.    * @return {boolean}
  472.    */
  473.   static isVisionOS() {
  474.     if (!shaka.util.Platform.isMac()) {
  475.       return false;
  476.     }
  477.     if (!('xr' in navigator)) {
  478.       return false;
  479.     }
  480.     return true;
  481.   }
  483.   /**
  484.    * Checks is non-Apple STB based on Webkit.
  485.    * @return {boolean}
  486.    */
  487.   static isWebkitSTB() {
  488.     return shaka.util.Platform.isAppleVendor_() &&
  489.         !shaka.util.Platform.isApple();
  490.   }
  492.   /**
  493.    * Return true if the platform is a Windows, regardless of the browser.
  494.    *
  495.    * @return {boolean}
  496.    */
  497.   static isWindows() {
  498.     // Try the newer standard first.
  499.     if (navigator.userAgentData && navigator.userAgentData.platform) {
  500.       return navigator.userAgentData.platform.toLowerCase() == 'windows';
  501.     }
  502.     // Fall back to the old API, with less strict matching.
  503.     if (!navigator.platform) {
  504.       return false;
  505.     }
  506.     return navigator.platform.toLowerCase().includes('win32');
  507.   }
  509.   /**
  510.    * Return true if the platform is a Android, regardless of the browser.
  511.    *
  512.    * @return {boolean}
  513.    */
  514.   static isAndroid() {
  515.     if (navigator.userAgentData && navigator.userAgentData.platform) {
  516.       return navigator.userAgentData.platform.toLowerCase() == 'android';
  517.     }
  518.     return shaka.util.Platform.userAgentContains_('Android');
  519.   }
  521.   /**
  522.    * Return true if the platform is a Fuchsia, regardless of the browser.
  523.    *
  524.    * @return {boolean}
  525.    */
  526.   static isFuchsia() {
  527.     if (navigator.userAgentData && navigator.userAgentData.platform) {
  528.       return navigator.userAgentData.platform.toLowerCase() == 'fuchsia';
  529.     }
  530.     return shaka.util.Platform.userAgentContains_('Fuchsia');
  531.   }
  533.   /**
  534.    * Return true if the platform is controlled by a remote control.
  535.    *
  536.    * @return {boolean}
  537.    */
  538.   static isSmartTV() {
  539.     const Platform = shaka.util.Platform;
  540.     if (Platform.isTizen() || Platform.isWebOS() ||
  541.         Platform.isXboxOne() || Platform.isPS4() ||
  542.         Platform.isPS5() || Platform.isChromecast() ||
  543.         Platform.isHisense() || Platform.isWebkitSTB()) {
  544.       return true;
  545.     }
  546.     return false;
  547.   }
  549.   /**
  550.    * Check if the user agent contains a key. This is the best way we know of
  551.    * right now to detect platforms. If there is a better way, please send a
  552.    * PR.
  553.    *
  554.    * @param {string} key
  555.    * @return {boolean}
  556.    * @private
  557.    */
  558.   static userAgentContains_(key) {
  559.     const userAgent = navigator.userAgent || '';
  560.     return userAgent.includes(key);
  561.   }
  563.   /**
  564.    * @return {boolean}
  565.    * @private
  566.    */
  567.   static isAppleVendor_() {
  568.     return (navigator.vendor || '').includes('Apple');
  569.   }
  571.   /**
  572.    * For canPlayType queries, we just need any instance.
  573.    *
  574.    * First, use a cached element from a previous query.
  575.    * Second, search the page for one.
  576.    * Third, create a temporary one.
  577.    *
  578.    * Cached elements expire in one second so that they can be GC'd or removed.
  579.    *
  580.    * @return {!HTMLMediaElement}
  581.    */
  582.   static anyMediaElement() {
  583.     const Platform = shaka.util.Platform;
  584.     if (Platform.cachedMediaElement_) {
  585.       return Platform.cachedMediaElement_;
  586.     }
  588.     if (!Platform.cacheExpirationTimer_) {
  589.       Platform.cacheExpirationTimer_ = new shaka.util.Timer(() => {
  590.         Platform.cachedMediaElement_ = null;
  591.       });
  592.     }
  594.     Platform.cachedMediaElement_ = /** @type {HTMLMediaElement} */(
  595.       document.getElementsByTagName('video')[0] ||
  596.       document.getElementsByTagName('audio')[0]);
  598.     if (!Platform.cachedMediaElement_) {
  599.       Platform.cachedMediaElement_ = /** @type {!HTMLMediaElement} */(
  600.         document.createElement('video'));
  601.     }
  603.     Platform.cacheExpirationTimer_.tickAfter(/* seconds= */ 1);
  604.     return Platform.cachedMediaElement_;
  605.   }
  607.   /**
  608.    * Returns true if the platform requires encryption information in all init
  609.    * segments.  For such platforms, MediaSourceEngine will attempt to work
  610.    * around a lack of such info by inserting fake encryption information into
  611.    * initialization segments.
  612.    *
  613.    * @param {?string} keySystem
  614.    * @return {boolean}
  615.    * @see https://github.com/shaka-project/shaka-player/issues/2759
  616.    */
  617.   static requiresEncryptionInfoInAllInitSegments(keySystem) {
  618.     const Platform = shaka.util.Platform;
  619.     const isPlayReady = shaka.drm.DrmUtils.isPlayReadyKeySystem(keySystem);
  620.     return Platform.isTizen() || Platform.isXboxOne() || Platform.isOrange() ||
  621.       (Platform.isEdge() && Platform.isWindows() && isPlayReady);
  622.   }
  624.   /**
  625.    * Returns true if the platform requires AC-3 signalling in init
  626.    * segments to be replaced with EC-3 signalling.
  627.    * For such platforms, MediaSourceEngine will attempt to work
  628.    * around it by inserting fake EC-3 signalling into
  629.    * initialization segments.
  630.    *
  631.    * @return {boolean}
  632.    */
  633.   static requiresEC3InitSegments() {
  634.     return shaka.util.Platform.isTizen3();
  635.   }
  637.   /**
  638.    * Returns true if the platform supports SourceBuffer "sequence mode".
  639.    *
  640.    * @return {boolean}
  641.    */
  642.   static supportsSequenceMode() {
  643.     const Platform = shaka.util.Platform;
  644.     if (Platform.isTizen3() || Platform.isTizen2() ||
  645.         Platform.isWebOS3() || Platform.isPS4() || Platform.isPS5()) {
  646.       return false;
  647.     }
  648.     // See: https://bugs.webkit.org/show_bug.cgi?id=210341
  649.     const safariVersion = Platform.safariVersion();
  650.     if (Platform.isWebkitSTB() && safariVersion != null && safariVersion < 15) {
  651.       return false;
  652.     }
  653.     return true;
  654.   }
  656.   /**
  657.    * Returns if codec switching SMOOTH is known reliable device support.
  658.    *
  659.    * Some devices are known not to support <code>SourceBuffer.changeType</code>
  660.    * well. These devices should use the reload strategy. If a device
  661.    * reports that it supports <code<changeType</code> but supports it unreliably
  662.    * it should be disallowed in this method.
  663.    *
  664.    * @return {boolean}
  665.    */
  666.   static supportsSmoothCodecSwitching() {
  667.     const Platform = shaka.util.Platform;
  668.     // All Tizen versions (up to Tizen 8) do not support SMOOTH so far.
  669.     // webOS seems to support SMOOTH from webOS 22.
  670.     if (Platform.isTizen() || Platform.isPS4() || Platform.isPS5() ||
  671.         Platform.isWebOS6()) {
  672.       return false;
  673.     }
  674.     // Older chromecasts without GoogleTV seem to not support SMOOTH properly.
  675.     if (Platform.isOlderChromecast()) {
  676.       return false;
  677.     }
  678.     // See: https://chromium-review.googlesource.com/c/chromium/src/+/4577759
  679.     if (Platform.isWindows() && Platform.isEdge()) {
  680.       return false;
  681.     }
  682.     return true;
  683.   }
  685.   /**
  686.    * On some platforms, such as v1 Chromecasts, the act of seeking can take a
  687.    * significant amount of time.
  688.    *
  689.    * @return {boolean}
  690.    */
  691.   static isSeekingSlow() {
  692.     const Platform = shaka.util.Platform;
  693.     if (Platform.isChromecast()) {
  694.       if (Platform.isAndroidCastDevice()) {
  695.         // Android-based Chromecasts are new enough to not be a problem.
  696.         return false;
  697.       } else {
  698.         return true;
  699.       }
  700.     }
  701.     return false;
  702.   }
  704.   /**
  705.    * Returns true if MediaKeys is polyfilled by the specified polyfill.
  706.    *
  707.    * @param {string} polyfillType
  708.    * @return {boolean}
  709.    */
  710.   static isMediaKeysPolyfilled(polyfillType) {
  711.     return polyfillType === window.shakaMediaKeysPolyfill;
  712.   }
  715.   /**
  716.    * Detect the maximum resolution that the platform's hardware can handle.
  717.    *
  718.    * @return {!Promise<shaka.extern.Resolution>}
  719.    */
  720.   static async detectMaxHardwareResolution() {
  721.     const Platform = shaka.util.Platform;
  723.     /** @type {shaka.extern.Resolution} */
  724.     const maxResolution = {
  725.       width: Infinity,
  726.       height: Infinity,
  727.     };
  729.     if (Platform.isChromecast()) {
  730.       // In our tests, the original Chromecast seems to have trouble decoding
  731.       // above 1080p. It would be a waste to select a higher res anyway, given
  732.       // that the device only outputs 1080p to begin with.
  733.       // Chromecast has an extension to query the device/display's resolution.
  734.       const hasCanDisplayType = window.cast && cast.__platform__ &&
  735.           cast.__platform__.canDisplayType;
  737.       // Some hub devices can only do 720p. Default to that.
  738.       maxResolution.width = 1280;
  739.       maxResolution.height = 720;
  741.       try {
  742.         if (hasCanDisplayType && await cast.__platform__.canDisplayType(
  743.             'video/mp4; codecs="avc1.640028"; width=3840; height=2160')) {
  744.           // The device and display can both do 4k. Assume a 4k limit.
  745.           maxResolution.width = 3840;
  746.           maxResolution.height = 2160;
  747.         } else if (hasCanDisplayType && await cast.__platform__.canDisplayType(
  748.             'video/mp4; codecs="avc1.640028"; width=1920; height=1080')) {
  749.           // Most Chromecasts can do 1080p.
  750.           maxResolution.width = 1920;
  751.           maxResolution.height = 1080;
  752.         }
  753.       } catch (error) {
  754.         // This shouldn't generally happen. Log the error.
  755.         shaka.log.alwaysError('Failed to check canDisplayType:', error);
  756.         // Now ignore the error and let the 720p default stand.
  757.       }
  758.     } else if (Platform.isTizen()) {
  759.       maxResolution.width = 1920;
  760.       maxResolution.height = 1080;
  761.       try {
  762.         if (webapis.systeminfo && webapis.systeminfo.getMaxVideoResolution) {
  763.           const maxVideoResolution =
  764.               webapis.systeminfo.getMaxVideoResolution();
  765.           maxResolution.width = maxVideoResolution.width;
  766.           maxResolution.height = maxVideoResolution.height;
  767.         } else {
  768.           if (webapis.productinfo.is8KPanelSupported &&
  769.               webapis.productinfo.is8KPanelSupported()) {
  770.             maxResolution.width = 7680;
  771.             maxResolution.height = 4320;
  772.           } else if (webapis.productinfo.isUdPanelSupported &&
  773.               webapis.productinfo.isUdPanelSupported()) {
  774.             maxResolution.width = 3840;
  775.             maxResolution.height = 2160;
  776.           }
  777.         }
  778.       } catch (e) {
  779.         shaka.log.alwaysWarn('Tizen: Error detecting screen size, default ' +
  780.             'screen size 1920x1080.');
  781.       }
  782.     } else if (Platform.isWebOS()) {
  783.       try {
  784.         const deviceInfo =
  785.         /** @type {{screenWidth: number, screenHeight: number}} */(
  786.             JSON.parse(window.PalmSystem.deviceInfo));
  787.         // WebOS has always been able to do 1080p.  Assume a 1080p limit.
  788.         maxResolution.width = Math.max(1920, deviceInfo['screenWidth']);
  789.         maxResolution.height = Math.max(1080, deviceInfo['screenHeight']);
  790.       } catch (e) {
  791.         shaka.log.alwaysWarn('WebOS: Error detecting screen size, default ' +
  792.             'screen size 1920x1080.');
  793.         maxResolution.width = 1920;
  794.         maxResolution.height = 1080;
  795.       }
  796.     } else if (Platform.isHisense()) {
  797.       let supports4k = null;
  798.       if (window.Hisense_Get4KSupportState) {
  799.         try {
  800.           // eslint-disable-next-line new-cap
  801.           supports4k = window.Hisense_Get4KSupportState();
  802.         } catch (e) {
  803.           shaka.log.debug('Hisense: Failed to get 4K support state', e);
  804.         }
  805.       }
  806.       if (supports4k == null) {
  807.         // If API is not there or not working for whatever reason, fallback to
  808.         // user agent check, as it contains UHD or FHD info.
  809.         supports4k = Platform.userAgentContains_('UHD');
  810.       }
  811.       if (supports4k) {
  812.         maxResolution.width = 3840;
  813.         maxResolution.height = 2160;
  814.       } else {
  815.         maxResolution.width = 1920;
  816.         maxResolution.height = 1080;
  817.       }
  818.     } else if (Platform.isPS4() || Platform.isPS5()) {
  819.       let supports4K = false;
  820.       try {
  821.         const result = await window.msdk.device.getDisplayInfo();
  822.         supports4K = result.resolution === '4K';
  823.       } catch (e) {
  824.         try {
  825.           const result = await window.msdk.device.getDisplayInfoImmediate();
  826.           supports4K = result.resolution === '4K';
  827.         } catch (e) {
  828.           shaka.log.alwaysWarn(
  829.               'PlayStation: Failed to get the display info:', e);
  830.         }
  831.       }
  832.       if (supports4K) {
  833.         maxResolution.width = 3840;
  834.         maxResolution.height = 2160;
  835.       } else {
  836.         maxResolution.width = 1920;
  837.         maxResolution.height = 1080;
  838.       }
  839.     } else {
  840.       // For Xbox and UWP apps.
  841.       let winRT = undefined;
  842.       try {
  843.         // Try to access to WinRT for WebView, if it's not defined,
  844.         // try to access to WinRT for WebView2, if it's not defined either,
  845.         // let it throw.
  846.         if (typeof Windows !== 'undefined') {
  847.           winRT = Windows;
  848.         } else {
  849.           winRT = chrome.webview.hostObjects.sync.Windows;
  850.         }
  851.       } catch (e) {}
  852.       if (winRT) {
  853.         maxResolution.width = 1920;
  854.         maxResolution.height = 1080;
  855.         try {
  856.           const protectionCapabilities =
  857.               new winRT.Media.Protection.ProtectionCapabilities();
  858.           const protectionResult =
  859.               winRT.Media.Protection.ProtectionCapabilityResult;
  860.           // isTypeSupported may return "maybe", which means the operation
  861.           // is not completed. This means we need to retry
  862.           // https://learn.microsoft.com/en-us/uwp/api/windows.media.protection.protectioncapabilityresult?view=winrt-22621
  863.           let result = null;
  864.           const type =
  865.               'video/mp4;codecs="hvc1,mp4a";features="decode-res-x=3840,' +
  866.               'decode-res-y=2160,decode-bitrate=20000,decode-fps=30,' +
  867.               'decode-bpc=10,display-res-x=3840,display-res-y=2160,' +
  868.               'display-bpc=8"';
  869.           const keySystem = 'com.microsoft.playready.recommendation';
  870.           do {
  871.             result = protectionCapabilities.isTypeSupported(type, keySystem);
  872.           } while (result === protectionResult.maybe);
  873.           if (result === protectionResult.probably) {
  874.             maxResolution.width = 3840;
  875.             maxResolution.height = 2160;
  876.           }
  877.         } catch (e) {
  878.           shaka.log.alwaysWarn('Xbox: Error detecting screen size, default ' +
  879.               'screen size 1920x1080.');
  880.         }
  881.       } else if (Platform.isXboxOne()) {
  882.         maxResolution.width = 1920;
  883.         maxResolution.height = 1080;
  884.         shaka.log.alwaysWarn('Xbox: Error detecting screen size, default ' +
  885.             'screen size 1920x1080.');
  886.       }
  887.     }
  888.     return maxResolution;
  889.   }
  890. };
  892. /** @private {shaka.util.Timer} */
  893. shaka.util.Platform.cacheExpirationTimer_ = null;
  895. /** @private {HTMLMediaElement} */
  896. shaka.util.Platform.cachedMediaElement_ = null;