Source: lib/text/ttml_text_parser.js

  1. /*! @license
  2.  * Shaka Player
  3.  * Copyright 2016 Google LLC
  4.  * SPDX-License-Identifier: Apache-2.0
  5.  */
  7. goog.provide('shaka.text.TtmlTextParser');
  9. goog.require('goog.asserts');
  10. goog.require('goog.Uri');
  11. goog.require('shaka.log');
  12. goog.require('shaka.text.Cue');
  13. goog.require('shaka.text.CueRegion');
  14. goog.require('shaka.text.TextEngine');
  15. goog.require('shaka.util.ArrayUtils');
  16. goog.require('shaka.util.Error');
  17. goog.require('shaka.util.StringUtils');
  18. goog.require('shaka.util.XmlUtils');
  21. /**
  22.  * @implements {shaka.extern.TextParser}
  23.  * @export
  24.  */
  25. shaka.text.TtmlTextParser = class {
  26.   /**
  27.    * @override
  28.    * @export
  29.    */
  30.   parseInit(data) {
  31.     goog.asserts.assert(false, 'TTML does not have init segments');
  32.   }
  34.   /**
  35.    * @override
  36.    * @export
  37.    */
  38.   setSequenceMode(sequenceMode) {
  39.     // Unused.
  40.   }
  42.   /**
  43.    * @override
  44.    * @export
  45.    */
  46.   setManifestType(manifestType) {
  47.     // Unused.
  48.   }
  50.   /**
  51.    * @override
  52.    * @export
  53.    */
  54.   parseMedia(data, time, uri) {
  55.     const TtmlTextParser = shaka.text.TtmlTextParser;
  56.     const XmlUtils = shaka.util.XmlUtils;
  57.     const ttpNs = TtmlTextParser.parameterNs_;
  58.     const ttsNs = TtmlTextParser.styleNs_;
  59.     const str = shaka.util.StringUtils.fromUTF8(data);
  60.     const cues = [];
  62.     // dont try to parse empty string as
  63.     // DOMParser will not throw error but return an errored xml
  64.     if (str == '') {
  65.       return cues;
  66.     }
  68.     const tt = XmlUtils.parseXmlString(str, 'tt');
  69.     if (!tt) {
  70.       throw new shaka.util.Error(
  71.           shaka.util.Error.Severity.CRITICAL,
  72.           shaka.util.Error.Category.TEXT,
  73.           shaka.util.Error.Code.INVALID_XML,
  74.           'Failed to parse TTML.');
  75.     }
  77.     const body = tt.getElementsByTagName('body')[0];
  78.     if (!body) {
  79.       return [];
  80.     }
  82.     // Get the framerate, subFrameRate and frameRateMultiplier if applicable.
  83.     const frameRate = XmlUtils.getAttributeNSList(tt, ttpNs, 'frameRate');
  84.     const subFrameRate = XmlUtils.getAttributeNSList(
  85.         tt, ttpNs, 'subFrameRate');
  86.     const frameRateMultiplier =
  87.         XmlUtils.getAttributeNSList(tt, ttpNs, 'frameRateMultiplier');
  88.     const tickRate = XmlUtils.getAttributeNSList(tt, ttpNs, 'tickRate');
  90.     const cellResolution = XmlUtils.getAttributeNSList(
  91.         tt, ttpNs, 'cellResolution');
  92.     const spaceStyle = tt.getAttribute('xml:space') || 'default';
  93.     const extent = XmlUtils.getAttributeNSList(tt, ttsNs, 'extent');
  95.     if (spaceStyle != 'default' && spaceStyle != 'preserve') {
  96.       throw new shaka.util.Error(
  97.           shaka.util.Error.Severity.CRITICAL,
  98.           shaka.util.Error.Category.TEXT,
  99.           shaka.util.Error.Code.INVALID_XML,
  100.           'Invalid xml:space value: ' + spaceStyle);
  101.     }
  102.     const whitespaceTrim = spaceStyle == 'default';
  104.     const rateInfo = new TtmlTextParser.RateInfo_(
  105.         frameRate, subFrameRate, frameRateMultiplier, tickRate);
  107.     const cellResolutionInfo =
  108.       TtmlTextParser.getCellResolution_(cellResolution);
  110.     const metadata = tt.getElementsByTagName('metadata')[0];
  111.     const metadataElements = metadata ? XmlUtils.getChildren(metadata) : [];
  112.     const styles = Array.from(tt.getElementsByTagName('style'));
  113.     const regionElements = Array.from(tt.getElementsByTagName('region'));
  115.     const cueRegions = [];
  116.     for (const region of regionElements) {
  117.       const cueRegion =
  118.           TtmlTextParser.parseCueRegion_(region, styles, extent);
  119.       if (cueRegion) {
  120.         cueRegions.push(cueRegion);
  121.       }
  122.     }
  124.     // A <body> element should only contain <div> elements, not <p> or <span>
  125.     // elements.  We used to allow this, but it is non-compliant, and the
  126.     // loose nature of our previous parser made it difficult to implement TTML
  127.     // nesting more fully.
  128.     if (XmlUtils.findChildren(body, 'p').length) {
  129.       throw new shaka.util.Error(
  130.           shaka.util.Error.Severity.CRITICAL,
  131.           shaka.util.Error.Category.TEXT,
  132.           shaka.util.Error.Code.INVALID_TEXT_CUE,
  133.           '<p> can only be inside <div> in TTML');
  134.     }
  136.     for (const div of XmlUtils.findChildren(body, 'div')) {
  137.       // A <div> element should only contain <p>, not <span>.
  138.       if (XmlUtils.findChildren(div, 'span').length) {
  139.         throw new shaka.util.Error(
  140.             shaka.util.Error.Severity.CRITICAL,
  141.             shaka.util.Error.Category.TEXT,
  142.             shaka.util.Error.Code.INVALID_TEXT_CUE,
  143.             '<span> can only be inside <p> in TTML');
  144.       }
  145.     }
  147.     const cue = TtmlTextParser.parseCue_(
  148.         body, time, rateInfo, metadataElements, styles,
  149.         regionElements, cueRegions, whitespaceTrim,
  150.         cellResolutionInfo, /* parentCueElement= */ null,
  151.         /* isContent= */ false, uri);
  152.     if (cue) {
  153.       // According to the TTML spec, backgrounds default to transparent.
  154.       // So default the background of the top-level element to transparent.
  155.       // Nested elements may override that background color already.
  156.       if (!cue.backgroundColor) {
  157.         cue.backgroundColor = 'transparent';
  158.       }
  159.       cues.push(cue);
  160.     }
  162.     return cues;
  163.   }
  165.   /**
  166.    * Parses a TTML node into a Cue.
  167.    *
  168.    * @param {!Node} cueNode
  169.    * @param {shaka.extern.TextParser.TimeContext} timeContext
  170.    * @param {!shaka.text.TtmlTextParser.RateInfo_} rateInfo
  171.    * @param {!Array.<!Element>} metadataElements
  172.    * @param {!Array.<!Element>} styles
  173.    * @param {!Array.<!Element>} regionElements
  174.    * @param {!Array.<!shaka.text.CueRegion>} cueRegions
  175.    * @param {boolean} whitespaceTrim
  176.    * @param {?{columns: number, rows: number}} cellResolution
  177.    * @param {?Element} parentCueElement
  178.    * @param {boolean} isContent
  179.    * @param {?(string|undefined)} uri
  180.    * @return {shaka.text.Cue}
  181.    * @private
  182.    */
  183.   static parseCue_(
  184.       cueNode, timeContext, rateInfo, metadataElements, styles, regionElements,
  185.       cueRegions, whitespaceTrim, cellResolution, parentCueElement, isContent,
  186.       uri) {
  187.     /** @type {Element} */
  188.     let cueElement;
  189.     /** @type {Element} */
  190.     let parentElement = /** @type {Element} */ (cueNode.parentNode);
  192.     if (cueNode.nodeType == Node.COMMENT_NODE) {
  193.       // The comments do not contain information that interests us here.
  194.       return null;
  195.     }
  197.     if (cueNode.nodeType == Node.TEXT_NODE) {
  198.       if (!isContent) {
  199.         // Ignore text elements outside the content. For example, whitespace
  200.         // on the same lexical level as the <p> elements, in a document with
  201.         // xml:space="preserve", should not be renderer.
  202.         return null;
  203.       }
  204.       // This should generate an "anonymous span" according to the TTML spec.
  205.       // So pretend the element was a <span>.  parentElement was set above, so
  206.       // we should still be able to correctly traverse up for timing
  207.       // information later.
  208.       const span = document.createElement('span');
  209.       span.textContent = cueNode.textContent;
  210.       cueElement = span;
  211.     } else {
  212.       goog.asserts.assert(cueNode.nodeType == Node.ELEMENT_NODE,
  213.           'nodeType should be ELEMENT_NODE!');
  214.       cueElement = /** @type {!Element} */(cueNode);
  215.     }
  216.     goog.asserts.assert(cueElement, 'cueElement should be non-null!');
  218.     let imageElement = null;
  219.     for (const nameSpace of shaka.text.TtmlTextParser.smpteNsList_) {
  220.       imageElement = shaka.text.TtmlTextParser.getElementsFromCollection_(
  221.           cueElement, 'backgroundImage', metadataElements, '#',
  222.           nameSpace)[0];
  223.       if (imageElement) {
  224.         break;
  225.       }
  226.     }
  228.     let imageUri = null;
  229.     const backgroundImage = shaka.util.XmlUtils.getAttributeNSList(
  230.         cueElement,
  231.         shaka.text.TtmlTextParser.smpteNsList_,
  232.         'backgroundImage');
  233.     if (uri && backgroundImage && !backgroundImage.startsWith('#')) {
  234.       const baseUri = new goog.Uri(uri);
  235.       const relativeUri = new goog.Uri(backgroundImage);
  236.       const newUri = baseUri.resolve(relativeUri).toString();
  237.       if (newUri) {
  238.         imageUri = newUri;
  239.       }
  240.     }
  242.     if (cueNode.nodeName == 'p' || imageElement || imageUri) {
  243.       isContent = true;
  244.     }
  246.     const parentIsContent = isContent;
  248.     const spaceStyle = cueElement.getAttribute('xml:space') ||
  249.         (whitespaceTrim ? 'default' : 'preserve');
  251.     const localWhitespaceTrim = spaceStyle == 'default';
  253.     // Parse any nested cues first.
  254.     const isTextNode = (node) => {
  255.       return node.nodeType == Node.TEXT_NODE;
  256.     };
  257.     const isLeafNode = Array.from(cueElement.childNodes).every(isTextNode);
  258.     const nestedCues = [];
  259.     if (!isLeafNode) {
  260.       // Otherwise, recurse into the children.  Text nodes will convert into
  261.       // anonymous spans, which will then be leaf nodes.
  262.       for (const childNode of cueElement.childNodes) {
  263.         const nestedCue = shaka.text.TtmlTextParser.parseCue_(
  264.             childNode,
  265.             timeContext,
  266.             rateInfo,
  267.             metadataElements,
  268.             styles,
  269.             regionElements,
  270.             cueRegions,
  271.             localWhitespaceTrim,
  272.             cellResolution,
  273.             cueElement,
  274.             isContent,
  275.             uri,
  276.         );
  278.         // This node may or may not generate a nested cue.
  279.         if (nestedCue) {
  280.           nestedCues.push(nestedCue);
  281.         }
  282.       }
  283.     }
  285.     const isNested = /** @type {boolean} */ (parentCueElement != null);
  287.     // In this regex, "\S" means "non-whitespace character".
  288.     const hasTextContent = /\S/.test(cueElement.textContent);
  289.     const hasTimeAttributes =
  290.         cueElement.hasAttribute('begin') ||
  291.         cueElement.hasAttribute('end') ||
  292.         cueElement.hasAttribute('dur');
  294.     if (!hasTimeAttributes && !hasTextContent && cueElement.tagName != 'br' &&
  295.         nestedCues.length == 0) {
  296.       if (!isNested) {
  297.         // Disregards empty <p> elements without time attributes nor content.
  298.         // <p begin="..." smpte:backgroundImage="..." /> will go through,
  299.         // as some information could be held by its attributes.
  300.         // <p /> won't, as it would not be displayed.
  301.         return null;
  302.       } else if (localWhitespaceTrim) {
  303.         // Disregards empty anonymous spans when (local) trim is true.
  304.         return null;
  305.       }
  306.     }
  308.     // Get local time attributes.
  309.     let {start, end} = shaka.text.TtmlTextParser.parseTime_(
  310.         cueElement, rateInfo);
  311.     // Resolve local time relative to parent elements.  Time elements can appear
  312.     // all the way up to 'body', but not 'tt'.
  313.     while (parentElement && parentElement.nodeType == Node.ELEMENT_NODE &&
  314.         parentElement.tagName != 'tt') {
  315.       ({start, end} = shaka.text.TtmlTextParser.resolveTime_(
  316.           parentElement, rateInfo, start, end));
  317.       parentElement = /** @type {Element} */(parentElement.parentNode);
  318.     }
  320.     if (start == null) {
  321.       start = 0;
  322.     }
  323.     start += timeContext.periodStart;
  325.     // If end is null, that means the duration is effectively infinite.
  326.     if (end == null) {
  327.       end = Infinity;
  328.     } else {
  329.       end += timeContext.periodStart;
  330.     }
  332.     // Clip times to segment boundaries.
  333.     // https://github.com/shaka-project/shaka-player/issues/4631
  334.     start = Math.max(start, timeContext.segmentStart);
  335.     end = Math.min(end, timeContext.segmentEnd);
  337.     if (!hasTimeAttributes && nestedCues.length > 0) {
  338.       // If no time is defined for this cue, base the timing information on
  339.       // the time of the nested cues. In the case of multiple nested cues with
  340.       // different start times, it is the text displayer's responsibility to
  341.       // make sure that only the appropriate nested cue is drawn at any given
  342.       // time.
  343.       start = Infinity;
  344.       end = 0;
  345.       for (const cue of nestedCues) {
  346.         start = Math.min(start, cue.startTime);
  347.         end = Math.max(end, cue.endTime);
  348.       }
  349.     }
  351.     if (cueElement.tagName == 'br') {
  352.       const cue = new shaka.text.Cue(start, end, '');
  353.       cue.lineBreak = true;
  354.       return cue;
  355.     }
  357.     let payload = '';
  358.     if (isLeafNode) {
  359.       // If the childNodes are all text, this is a leaf node.  Get the payload.
  360.       payload = cueElement.textContent;
  361.       if (localWhitespaceTrim) {
  362.         // Trim leading and trailing whitespace.
  363.         payload = payload.trim();
  364.         // Collapse multiple spaces into one.
  365.         payload = payload.replace(/\s+/g, ' ');
  366.       }
  367.     }
  369.     const cue = new shaka.text.Cue(start, end, payload);
  370.     cue.nestedCues = nestedCues;
  372.     if (!isContent) {
  373.       // If this is not a <p> element or a <div> with images, and it has no
  374.       // parent that was a <p> element, then it's part of the outer containers
  375.       // (e.g. the <body> or a normal <div> element within it).
  376.       cue.isContainer = true;
  377.     }
  379.     if (cellResolution) {
  380.       cue.cellResolution = cellResolution;
  381.     }
  383.     // Get other properties if available.
  384.     const regionElement = shaka.text.TtmlTextParser.getElementsFromCollection_(
  385.         cueElement, 'region', regionElements, /* prefix= */ '')[0];
  386.     // Do not actually apply that region unless it is non-inherited, though.
  387.     // This makes it so that, if a parent element has a region, the children
  388.     // don't also all independently apply the positioning of that region.
  389.     if (cueElement.hasAttribute('region')) {
  390.       if (regionElement && regionElement.getAttribute('xml:id')) {
  391.         const regionId = regionElement.getAttribute('xml:id');
  392.         cue.region = cueRegions.filter((region) => region.id == regionId)[0];
  393.       }
  394.     }
  396.     let regionElementForStyle = regionElement;
  397.     if (parentCueElement && isNested && !cueElement.getAttribute('region') &&
  398.       !cueElement.getAttribute('style')) {
  399.       regionElementForStyle =
  400.           shaka.text.TtmlTextParser.getElementsFromCollection_(
  401.               parentCueElement, 'region', regionElements, /* prefix= */ '')[0];
  402.     }
  404.     shaka.text.TtmlTextParser.addStyle_(
  405.         cue,
  406.         cueElement,
  407.         regionElementForStyle,
  408.         imageElement,
  409.         imageUri,
  410.         styles,
  411.         /** isNested= */ parentIsContent, // "nested in a <div>" doesn't count.
  412.         /** isLeaf= */ (nestedCues.length == 0));
  414.     return cue;
  415.   }
  417.   /**
  418.    * Parses an Element into a TextTrackCue or VTTCue.
  419.    *
  420.    * @param {!Element} regionElement
  421.    * @param {!Array.<!Element>} styles Defined in the top of tt  element and
  422.    * used principally for images.
  423.    * @param {?string} globalExtent
  424.    * @return {shaka.text.CueRegion}
  425.    * @private
  426.    */
  427.   static parseCueRegion_(regionElement, styles, globalExtent) {
  428.     const TtmlTextParser = shaka.text.TtmlTextParser;
  429.     const region = new shaka.text.CueRegion();
  430.     const id = regionElement.getAttribute('xml:id');
  431.     if (!id) {
  432.       shaka.log.warning('TtmlTextParser parser encountered a region with ' +
  433.                         'no id. Region will be ignored.');
  434.       return null;
  435.     }
  436.     region.id = id;
  438.     let globalResults = null;
  439.     if (globalExtent) {
  440.       globalResults = TtmlTextParser.percentValues_.exec(globalExtent) ||
  441.         TtmlTextParser.pixelValues_.exec(globalExtent);
  442.     }
  443.     const globalWidth = globalResults ? Number(globalResults[1]) : null;
  444.     const globalHeight = globalResults ? Number(globalResults[2]) : null;
  446.     let results = null;
  447.     let percentage = null;
  448.     const extent = TtmlTextParser.getStyleAttributeFromRegion_(
  449.         regionElement, styles, 'extent');
  450.     if (extent) {
  451.       percentage = TtmlTextParser.percentValues_.exec(extent);
  452.       results = percentage || TtmlTextParser.pixelValues_.exec(extent);
  453.       if (results != null) {
  454.         region.width = Number(results[1]);
  455.         region.height = Number(results[2]);
  457.         if (!percentage) {
  458.           if (globalWidth != null) {
  459.             region.width = region.width * 100 / globalWidth;
  460.           }
  461.           if (globalHeight != null) {
  462.             region.height = region.height * 100 / globalHeight;
  463.           }
  464.         }
  466.         region.widthUnits = percentage || globalWidth != null ?
  467.                            shaka.text.CueRegion.units.PERCENTAGE :
  468.                            shaka.text.CueRegion.units.PX;
  470.         region.heightUnits = percentage || globalHeight != null ?
  471.                            shaka.text.CueRegion.units.PERCENTAGE :
  472.                            shaka.text.CueRegion.units.PX;
  473.       }
  474.     }
  476.     const origin = TtmlTextParser.getStyleAttributeFromRegion_(
  477.         regionElement, styles, 'origin');
  478.     if (origin) {
  479.       percentage = TtmlTextParser.percentValues_.exec(origin);
  480.       results = percentage || TtmlTextParser.pixelValues_.exec(origin);
  481.       if (results != null) {
  482.         region.viewportAnchorX = Number(results[1]);
  483.         region.viewportAnchorY = Number(results[2]);
  485.         if (!percentage) {
  486.           if (globalHeight != null) {
  487.             region.viewportAnchorY = region.viewportAnchorY * 100 /
  488.               globalHeight;
  489.           }
  490.           if (globalWidth != null) {
  491.             region.viewportAnchorX = region.viewportAnchorX * 100 /
  492.               globalWidth;
  493.           }
  494.         } else if (!extent) {
  495.           region.width = 100 - region.viewportAnchorX;
  496.           region.widthUnits = shaka.text.CueRegion.units.PERCENTAGE;
  497.           region.height = 100 - region.viewportAnchorY;
  498.           region.heightUnits = shaka.text.CueRegion.units.PERCENTAGE;
  499.         }
  501.         region.viewportAnchorUnits = percentage || globalWidth != null ?
  502.                   shaka.text.CueRegion.units.PERCENTAGE :
  503.                   shaka.text.CueRegion.units.PX;
  504.       }
  505.     }
  507.     return region;
  508.   }
  510.   /**
  511.    * Adds applicable style properties to a cue.
  512.    *
  513.    * @param {!shaka.text.Cue} cue
  514.    * @param {!Element} cueElement
  515.    * @param {Element} region
  516.    * @param {Element} imageElement
  517.    * @param {?string} imageUri
  518.    * @param {!Array.<!Element>} styles
  519.    * @param {boolean} isNested
  520.    * @param {boolean} isLeaf
  521.    * @private
  522.    */
  523.   static addStyle_(
  524.       cue, cueElement, region, imageElement, imageUri, styles,
  525.       isNested, isLeaf) {
  526.     const TtmlTextParser = shaka.text.TtmlTextParser;
  527.     const Cue = shaka.text.Cue;
  529.     // Styles should be inherited from regions, if a style property is not
  530.     // associated with a Content element (or an anonymous span).
  531.     const shouldInheritRegionStyles = isNested || isLeaf;
  533.     const direction = TtmlTextParser.getStyleAttribute_(
  534.         cueElement, region, styles, 'direction', shouldInheritRegionStyles);
  535.     if (direction == 'rtl') {
  536.       cue.direction = Cue.direction.HORIZONTAL_RIGHT_TO_LEFT;
  537.     }
  539.     // Direction attribute specifies one-dimentional writing direction
  540.     // (left to right or right to left). Writing mode specifies that
  541.     // plus whether text is vertical or horizontal.
  542.     // They should not contradict each other. If they do, we give
  543.     // preference to writing mode.
  544.     const writingMode = TtmlTextParser.getStyleAttribute_(
  545.         cueElement, region, styles, 'writingMode', shouldInheritRegionStyles);
  546.     // Set cue's direction if the text is horizontal, and cue's writingMode if
  547.     // it's vertical.
  548.     if (writingMode == 'tb' || writingMode == 'tblr') {
  549.       cue.writingMode = Cue.writingMode.VERTICAL_LEFT_TO_RIGHT;
  550.     } else if (writingMode == 'tbrl') {
  551.       cue.writingMode = Cue.writingMode.VERTICAL_RIGHT_TO_LEFT;
  552.     } else if (writingMode == 'rltb' || writingMode == 'rl') {
  553.       cue.direction = Cue.direction.HORIZONTAL_RIGHT_TO_LEFT;
  554.     } else if (writingMode) {
  555.       cue.direction = Cue.direction.HORIZONTAL_LEFT_TO_RIGHT;
  556.     }
  558.     const align = TtmlTextParser.getStyleAttribute_(
  559.         cueElement, region, styles, 'textAlign', true);
  560.     if (align) {
  561.       cue.positionAlign = TtmlTextParser.textAlignToPositionAlign_[align];
  562.       cue.lineAlign = TtmlTextParser.textAlignToLineAlign_[align];
  564.       goog.asserts.assert(align.toUpperCase() in Cue.textAlign,
  565.           align.toUpperCase() + ' Should be in Cue.textAlign values!');
  567.       cue.textAlign = Cue.textAlign[align.toUpperCase()];
  568.     } else {
  569.       // Default value is START in the TTML spec: https://bit.ly/32OGmvo
  570.       // But to make the subtitle render consitent with other players and the
  571.       // shaka.text.Cue we use CENTER
  572.       cue.textAlign = Cue.textAlign.CENTER;
  573.     }
  575.     const displayAlign = TtmlTextParser.getStyleAttribute_(
  576.         cueElement, region, styles, 'displayAlign', true);
  577.     if (displayAlign) {
  578.       goog.asserts.assert(displayAlign.toUpperCase() in Cue.displayAlign,
  579.           displayAlign.toUpperCase() +
  580.                           ' Should be in Cue.displayAlign values!');
  581.       cue.displayAlign = Cue.displayAlign[displayAlign.toUpperCase()];
  582.     }
  584.     const color = TtmlTextParser.getStyleAttribute_(
  585.         cueElement, region, styles, 'color', shouldInheritRegionStyles);
  586.     if (color) {
  587.       cue.color = color;
  588.     }
  590.     // Background color should not be set on a container.  If this is a nested
  591.     // cue, you can set the background.  If it's a top-level that happens to
  592.     // also be a leaf, you can set the background.
  593.     // See https://github.com/shaka-project/shaka-player/issues/2623
  594.     // This used to be handled in the displayer, but that is confusing.  The Cue
  595.     // structure should reflect what you want to happen in the displayer, and
  596.     // the displayer shouldn't have to know about TTML.
  597.     const backgroundColor = TtmlTextParser.getStyleAttribute_(
  598.         cueElement, region, styles, 'backgroundColor',
  599.         shouldInheritRegionStyles);
  600.     if (backgroundColor) {
  601.       cue.backgroundColor = backgroundColor;
  602.     }
  604.     const border = TtmlTextParser.getStyleAttribute_(
  605.         cueElement, region, styles, 'border', shouldInheritRegionStyles);
  606.     if (border) {
  607.       cue.border = border;
  608.     }
  610.     const fontFamily = TtmlTextParser.getStyleAttribute_(
  611.         cueElement, region, styles, 'fontFamily', shouldInheritRegionStyles);
  612.     // See https://github.com/sandflow/imscJS/blob/1.1.3/src/main/js/html.js#L1384
  613.     if (fontFamily) {
  614.       switch (fontFamily) {
  615.         case 'monospaceSerif':
  616.           cue.fontFamily = 'Courier New,Liberation Mono,Courier,monospace';
  617.           break;
  618.         case 'proportionalSansSerif':
  619.           cue.fontFamily = 'Arial,Helvetica,Liberation Sans,sans-serif';
  620.           break;
  621.         case 'sansSerif':
  622.           cue.fontFamily = 'sans-serif';
  623.           break;
  624.         case 'monospaceSansSerif':
  625.           cue.fontFamily = 'Consolas,monospace';
  626.           break;
  627.         case 'proportionalSerif':
  628.           cue.fontFamily = 'serif';
  629.           break;
  630.         default:
  631.           cue.fontFamily = fontFamily;
  632.           break;
  633.       }
  634.     }
  636.     const fontWeight = TtmlTextParser.getStyleAttribute_(
  637.         cueElement, region, styles, 'fontWeight', shouldInheritRegionStyles);
  638.     if (fontWeight && fontWeight == 'bold') {
  639.       cue.fontWeight = Cue.fontWeight.BOLD;
  640.     }
  642.     const wrapOption = TtmlTextParser.getStyleAttribute_(
  643.         cueElement, region, styles, 'wrapOption', shouldInheritRegionStyles);
  644.     if (wrapOption && wrapOption == 'noWrap') {
  645.       cue.wrapLine = false;
  646.     } else {
  647.       cue.wrapLine = true;
  648.     }
  650.     const lineHeight = TtmlTextParser.getStyleAttribute_(
  651.         cueElement, region, styles, 'lineHeight', shouldInheritRegionStyles);
  652.     if (lineHeight && lineHeight.match(TtmlTextParser.unitValues_)) {
  653.       cue.lineHeight = lineHeight;
  654.     }
  656.     const fontSize = TtmlTextParser.getStyleAttribute_(
  657.         cueElement, region, styles, 'fontSize', shouldInheritRegionStyles);
  658.     if (fontSize) {
  659.       const isValidFontSizeUnit =
  660.           fontSize.match(TtmlTextParser.unitValues_) ||
  661.           fontSize.match(TtmlTextParser.percentValue_);
  663.       if (isValidFontSizeUnit) {
  664.         cue.fontSize = fontSize;
  665.       }
  666.     }
  668.     const fontStyle = TtmlTextParser.getStyleAttribute_(
  669.         cueElement, region, styles, 'fontStyle', shouldInheritRegionStyles);
  670.     if (fontStyle) {
  671.       goog.asserts.assert(fontStyle.toUpperCase() in Cue.fontStyle,
  672.           fontStyle.toUpperCase() +
  673.                           ' Should be in Cue.fontStyle values!');
  674.       cue.fontStyle = Cue.fontStyle[fontStyle.toUpperCase()];
  675.     }
  677.     if (imageElement) {
  678.       // According to the spec, we should use imageType (camelCase), but
  679.       // historically we have checked for imagetype (lowercase).
  680.       // This was the case since background image support was first introduced
  681.       // in PR #1859, in April 2019, and first released in v2.5.0.
  682.       // Now we check for both, although only imageType (camelCase) is to spec.
  683.       const backgroundImageType =
  684.           imageElement.getAttribute('imageType') ||
  685.           imageElement.getAttribute('imagetype');
  686.       const backgroundImageEncoding = imageElement.getAttribute('encoding');
  687.       const backgroundImageData = imageElement.textContent.trim();
  688.       if (backgroundImageType == 'PNG' &&
  689.           backgroundImageEncoding == 'Base64' &&
  690.           backgroundImageData) {
  691.         cue.backgroundImage = 'data:image/png;base64,' + backgroundImageData;
  692.       }
  693.     } else if (imageUri) {
  694.       cue.backgroundImage = imageUri;
  695.     }
  697.     const textOutline = TtmlTextParser.getStyleAttribute_(
  698.         cueElement, region, styles, 'textOutline', shouldInheritRegionStyles);
  699.     if (textOutline) {
  700.       // tts:textOutline isn't natively supported by browsers, but it can be
  701.       // mostly replicated using the non-standard -webkit-text-stroke-width and
  702.       // -webkit-text-stroke-color properties.
  703.       const split = textOutline.split(' ');
  704.       if (split[0].match(TtmlTextParser.unitValues_)) {
  705.         // There is no defined color, so default to the text color.
  706.         cue.textStrokeColor = cue.color;
  707.       } else {
  708.         cue.textStrokeColor = split[0];
  709.         split.shift();
  710.       }
  711.       if (split[0] && split[0].match(TtmlTextParser.unitValues_)) {
  712.         cue.textStrokeWidth = split[0];
  713.       } else {
  714.         // If there is no width, or the width is not a number, don't draw a
  715.         // border.
  716.         cue.textStrokeColor = '';
  717.       }
  718.       // There is an optional blur radius also, but we have no way of
  719.       // replicating that, so ignore it.
  720.     }
  722.     const letterSpacing = TtmlTextParser.getStyleAttribute_(
  723.         cueElement, region, styles, 'letterSpacing', shouldInheritRegionStyles);
  724.     if (letterSpacing && letterSpacing.match(TtmlTextParser.unitValues_)) {
  725.       cue.letterSpacing = letterSpacing;
  726.     }
  728.     const linePadding = TtmlTextParser.getStyleAttribute_(
  729.         cueElement, region, styles, 'linePadding', shouldInheritRegionStyles);
  730.     if (linePadding && linePadding.match(TtmlTextParser.unitValues_)) {
  731.       cue.linePadding = linePadding;
  732.     }
  734.     const opacity = TtmlTextParser.getStyleAttribute_(
  735.         cueElement, region, styles, 'opacity', shouldInheritRegionStyles);
  736.     if (opacity) {
  737.       cue.opacity = parseFloat(opacity);
  738.     }
  740.     // Text decoration is an array of values which can come both from the
  741.     // element's style or be inherited from elements' parent nodes. All of those
  742.     // values should be applied as long as they don't contradict each other. If
  743.     // they do, elements' own style gets preference.
  744.     const textDecorationRegion = TtmlTextParser.getStyleAttributeFromRegion_(
  745.         region, styles, 'textDecoration');
  746.     if (textDecorationRegion) {
  747.       TtmlTextParser.addTextDecoration_(cue, textDecorationRegion);
  748.     }
  750.     const textDecorationElement = TtmlTextParser.getStyleAttributeFromElement_(
  751.         cueElement, styles, 'textDecoration');
  752.     if (textDecorationElement) {
  753.       TtmlTextParser.addTextDecoration_(cue, textDecorationElement);
  754.     }
  756.     const textCombine = TtmlTextParser.getStyleAttribute_(
  757.         cueElement, region, styles, 'textCombine', shouldInheritRegionStyles);
  758.     if (textCombine) {
  759.       cue.textCombineUpright = textCombine;
  760.     }
  762.     const ruby = TtmlTextParser.getStyleAttribute_(
  763.         cueElement, region, styles, 'ruby', shouldInheritRegionStyles);
  764.     switch (ruby) {
  765.       case 'container':
  766.         cue.rubyTag = 'ruby';
  767.         break;
  768.       case 'text':
  769.         cue.rubyTag = 'rt';
  770.         break;
  771.     }
  772.   }
  774.   /**
  775.    * Parses text decoration values and adds/removes them to/from the cue.
  776.    *
  777.    * @param {!shaka.text.Cue} cue
  778.    * @param {string} decoration
  779.    * @private
  780.    */
  781.   static addTextDecoration_(cue, decoration) {
  782.     const Cue = shaka.text.Cue;
  783.     for (const value of decoration.split(' ')) {
  784.       switch (value) {
  785.         case 'underline':
  786.           if (!cue.textDecoration.includes(Cue.textDecoration.UNDERLINE)) {
  787.             cue.textDecoration.push(Cue.textDecoration.UNDERLINE);
  788.           }
  789.           break;
  790.         case 'noUnderline':
  791.           if (cue.textDecoration.includes(Cue.textDecoration.UNDERLINE)) {
  792.             shaka.util.ArrayUtils.remove(cue.textDecoration,
  793.                 Cue.textDecoration.UNDERLINE);
  794.           }
  795.           break;
  796.         case 'lineThrough':
  797.           if (!cue.textDecoration.includes(Cue.textDecoration.LINE_THROUGH)) {
  798.             cue.textDecoration.push(Cue.textDecoration.LINE_THROUGH);
  799.           }
  800.           break;
  801.         case 'noLineThrough':
  802.           if (cue.textDecoration.includes(Cue.textDecoration.LINE_THROUGH)) {
  803.             shaka.util.ArrayUtils.remove(cue.textDecoration,
  804.                 Cue.textDecoration.LINE_THROUGH);
  805.           }
  806.           break;
  807.         case 'overline':
  808.           if (!cue.textDecoration.includes(Cue.textDecoration.OVERLINE)) {
  809.             cue.textDecoration.push(Cue.textDecoration.OVERLINE);
  810.           }
  811.           break;
  812.         case 'noOverline':
  813.           if (cue.textDecoration.includes(Cue.textDecoration.OVERLINE)) {
  814.             shaka.util.ArrayUtils.remove(cue.textDecoration,
  815.                 Cue.textDecoration.OVERLINE);
  816.           }
  817.           break;
  818.       }
  819.     }
  820.   }
  822.   /**
  823.    * Finds a specified attribute on either the original cue element or its
  824.    * associated region and returns the value if the attribute was found.
  825.    *
  826.    * @param {!Element} cueElement
  827.    * @param {Element} region
  828.    * @param {!Array.<!Element>} styles
  829.    * @param {string} attribute
  830.    * @param {boolean=} shouldInheritRegionStyles
  831.    * @return {?string}
  832.    * @private
  833.    */
  834.   static getStyleAttribute_(cueElement, region, styles, attribute,
  835.       shouldInheritRegionStyles=true) {
  836.     // An attribute can be specified on region level or in a styling block
  837.     // associated with the region or original element.
  838.     const TtmlTextParser = shaka.text.TtmlTextParser;
  839.     const attr = TtmlTextParser.getStyleAttributeFromElement_(
  840.         cueElement, styles, attribute);
  841.     if (attr) {
  842.       return attr;
  843.     }
  845.     if (shouldInheritRegionStyles) {
  846.       return TtmlTextParser.getStyleAttributeFromRegion_(
  847.           region, styles, attribute);
  848.     }
  849.     return null;
  850.   }
  852.   /**
  853.    * Finds a specified attribute on the element's associated region
  854.    * and returns the value if the attribute was found.
  855.    *
  856.    * @param {Element} region
  857.    * @param {!Array.<!Element>} styles
  858.    * @param {string} attribute
  859.    * @return {?string}
  860.    * @private
  861.    */
  862.   static getStyleAttributeFromRegion_(region, styles, attribute) {
  863.     const XmlUtils = shaka.util.XmlUtils;
  864.     const ttsNs = shaka.text.TtmlTextParser.styleNs_;
  866.     if (!region) {
  867.       return null;
  868.     }
  870.     const attr = XmlUtils.getAttributeNSList(region, ttsNs, attribute);
  871.     if (attr) {
  872.       return attr;
  873.     }
  875.     return shaka.text.TtmlTextParser.getInheritedStyleAttribute_(
  876.         region, styles, attribute);
  877.   }
  879.   /**
  880.    * Finds a specified attribute on the cue element and returns the value
  881.    * if the attribute was found.
  882.    *
  883.    * @param {!Element} cueElement
  884.    * @param {!Array.<!Element>} styles
  885.    * @param {string} attribute
  886.    * @return {?string}
  887.    * @private
  888.    */
  889.   static getStyleAttributeFromElement_(cueElement, styles, attribute) {
  890.     const XmlUtils = shaka.util.XmlUtils;
  891.     const ttsNs = shaka.text.TtmlTextParser.styleNs_;
  893.     // Styling on elements should take precedence
  894.     // over the main styling attributes
  895.     const elementAttribute = XmlUtils.getAttributeNSList(
  896.         cueElement,
  897.         ttsNs,
  898.         attribute);
  900.     if (elementAttribute) {
  901.       return elementAttribute;
  902.     }
  903.     return shaka.text.TtmlTextParser.getInheritedStyleAttribute_(
  904.         cueElement, styles, attribute);
  905.   }
  907.   /**
  908.    * Finds a specified attribute on an element's styles and the styles those
  909.    * styles inherit from.
  910.    *
  911.    * @param {!Element} element
  912.    * @param {!Array.<!Element>} styles
  913.    * @param {string} attribute
  914.    * @return {?string}
  915.    * @private
  916.    */
  917.   static getInheritedStyleAttribute_(element, styles, attribute) {
  918.     const XmlUtils = shaka.util.XmlUtils;
  919.     const ttsNs = shaka.text.TtmlTextParser.styleNs_;
  920.     const ebuttsNs = shaka.text.TtmlTextParser.styleEbuttsNs_;
  922.     const inheritedStyles =
  923.         shaka.text.TtmlTextParser.getElementsFromCollection_(
  924.             element, 'style', styles, /* prefix= */ '');
  926.     let styleValue = null;
  928.     // The last value in our styles stack takes the precedence over the others
  929.     for (let i = 0; i < inheritedStyles.length; i++) {
  930.       // Check ebu namespace first.
  931.       let styleAttributeValue = XmlUtils.getAttributeNS(
  932.           inheritedStyles[i],
  933.           ebuttsNs,
  934.           attribute);
  936.       if (!styleAttributeValue) {
  937.         // Fall back to tts namespace.
  938.         styleAttributeValue = XmlUtils.getAttributeNSList(
  939.             inheritedStyles[i],
  940.             ttsNs,
  941.             attribute);
  942.       }
  944.       if (!styleAttributeValue) {
  945.         // Next, check inheritance.
  946.         // Styles can inherit from other styles, so traverse up that chain.
  947.         styleAttributeValue =
  948.             shaka.text.TtmlTextParser.getStyleAttributeFromElement_(
  949.                 inheritedStyles[i], styles, attribute);
  950.       }
  952.       if (styleAttributeValue) {
  953.         styleValue = styleAttributeValue;
  954.       }
  955.     }
  957.     return styleValue;
  958.   }
  961.   /**
  962.    * Selects items from |collection| whose id matches |attributeName|
  963.    * from |element|.
  964.    *
  965.    * @param {Element} element
  966.    * @param {string} attributeName
  967.    * @param {!Array.<Element>} collection
  968.    * @param {string} prefixName
  969.    * @param {string=} nsName
  970.    * @return {!Array.<!Element>}
  971.    * @private
  972.    */
  973.   static getElementsFromCollection_(
  974.       element, attributeName, collection, prefixName, nsName) {
  975.     const items = [];
  977.     if (!element || collection.length < 1) {
  978.       return items;
  979.     }
  981.     const attributeValue = shaka.text.TtmlTextParser.getInheritedAttribute_(
  982.         element, attributeName, nsName);
  984.     if (attributeValue) {
  985.       // There could be multiple items in one attribute
  986.       // <span style="style1 style2">A cue</span>
  987.       const itemNames = attributeValue.split(' ');
  989.       for (const name of itemNames) {
  990.         for (const item of collection) {
  991.           if ((prefixName + item.getAttribute('xml:id')) == name) {
  992.             items.push(item);
  993.             break;
  994.           }
  995.         }
  996.       }
  997.     }
  999.     return items;
  1000.   }
  1003.   /**
  1004.    * Traverses upwards from a given node until a given attribute is found.
  1005.    *
  1006.    * @param {!Element} element
  1007.    * @param {string} attributeName
  1008.    * @param {string=} nsName
  1009.    * @return {?string}
  1010.    * @private
  1011.    */
  1012.   static getInheritedAttribute_(element, attributeName, nsName) {
  1013.     let ret = null;
  1014.     const XmlUtils = shaka.util.XmlUtils;
  1015.     while (element) {
  1016.       ret = nsName ?
  1017.           XmlUtils.getAttributeNS(element, nsName, attributeName) :
  1018.           element.getAttribute(attributeName);
  1019.       if (ret) {
  1020.         break;
  1021.       }
  1023.       // Element.parentNode can lead to XMLDocument, which is not an Element and
  1024.       // has no getAttribute().
  1025.       const parentNode = element.parentNode;
  1026.       if (parentNode instanceof Element) {
  1027.         element = parentNode;
  1028.       } else {
  1029.         break;
  1030.       }
  1031.     }
  1032.     return ret;
  1033.   }
  1035.   /**
  1036.    * Factor parent/ancestor time attributes into the parsed time of a
  1037.    * child/descendent.
  1038.    *
  1039.    * @param {!Element} parentElement
  1040.    * @param {!shaka.text.TtmlTextParser.RateInfo_} rateInfo
  1041.    * @param {?number} start The child's start time
  1042.    * @param {?number} end The child's end time
  1043.    * @return {{start: ?number, end: ?number}}
  1044.    * @private
  1045.    */
  1046.   static resolveTime_(parentElement, rateInfo, start, end) {
  1047.     const parentTime = shaka.text.TtmlTextParser.parseTime_(
  1048.         parentElement, rateInfo);
  1050.     if (start == null) {
  1051.       // No start time of your own?  Inherit from the parent.
  1052.       start = parentTime.start;
  1053.     } else {
  1054.       // Otherwise, the start time is relative to the parent's start time.
  1055.       if (parentTime.start != null) {
  1056.         start += parentTime.start;
  1057.       }
  1058.     }
  1060.     if (end == null) {
  1061.       // No end time of your own?  Inherit from the parent.
  1062.       end = parentTime.end;
  1063.     } else {
  1064.       // Otherwise, the end time is relative to the parent's _start_ time.
  1065.       // This is not a typo.  Both times are relative to the parent's _start_.
  1066.       if (parentTime.start != null) {
  1067.         end += parentTime.start;
  1068.       }
  1069.     }
  1071.     return {start, end};
  1072.   }
  1074.   /**
  1075.    * Parse TTML time attributes from the given element.
  1076.    *
  1077.    * @param {!Element} element
  1078.    * @param {!shaka.text.TtmlTextParser.RateInfo_} rateInfo
  1079.    * @return {{start: ?number, end: ?number}}
  1080.    * @private
  1081.    */
  1082.   static parseTime_(element, rateInfo) {
  1083.     const start = shaka.text.TtmlTextParser.parseTimeAttribute_(
  1084.         element.getAttribute('begin'), rateInfo);
  1085.     let end = shaka.text.TtmlTextParser.parseTimeAttribute_(
  1086.         element.getAttribute('end'), rateInfo);
  1087.     const duration = shaka.text.TtmlTextParser.parseTimeAttribute_(
  1088.         element.getAttribute('dur'), rateInfo);
  1089.     if (end == null && duration != null) {
  1090.       end = start + duration;
  1091.     }
  1092.     return {start, end};
  1093.   }
  1095.   /**
  1096.    * Parses a TTML time from the given attribute text.
  1097.    *
  1098.    * @param {string} text
  1099.    * @param {!shaka.text.TtmlTextParser.RateInfo_} rateInfo
  1100.    * @return {?number}
  1101.    * @private
  1102.    */
  1103.   static parseTimeAttribute_(text, rateInfo) {
  1104.     let ret = null;
  1105.     const TtmlTextParser = shaka.text.TtmlTextParser;
  1107.     if (TtmlTextParser.timeColonFormatFrames_.test(text)) {
  1108.       ret = TtmlTextParser.parseColonTimeWithFrames_(rateInfo, text);
  1109.     } else if (TtmlTextParser.timeColonFormat_.test(text)) {
  1110.       ret = TtmlTextParser.parseTimeFromRegex_(
  1111.           TtmlTextParser.timeColonFormat_, text);
  1112.     } else if (TtmlTextParser.timeColonFormatMilliseconds_.test(text)) {
  1113.       ret = TtmlTextParser.parseTimeFromRegex_(
  1114.           TtmlTextParser.timeColonFormatMilliseconds_, text);
  1115.     } else if (TtmlTextParser.timeFramesFormat_.test(text)) {
  1116.       ret = TtmlTextParser.parseFramesTime_(rateInfo, text);
  1117.     } else if (TtmlTextParser.timeTickFormat_.test(text)) {
  1118.       ret = TtmlTextParser.parseTickTime_(rateInfo, text);
  1119.     } else if (TtmlTextParser.timeHMSFormat_.test(text)) {
  1120.       ret = TtmlTextParser.parseTimeFromRegex_(
  1121.           TtmlTextParser.timeHMSFormat_, text);
  1122.     } else if (text) {
  1123.       // It's not empty or null, but it doesn't match a known format.
  1124.       throw new shaka.util.Error(
  1125.           shaka.util.Error.Severity.CRITICAL,
  1126.           shaka.util.Error.Category.TEXT,
  1127.           shaka.util.Error.Code.INVALID_TEXT_CUE,
  1128.           'Could not parse cue time range in TTML');
  1129.     }
  1131.     return ret;
  1132.   }
  1134.   /**
  1135.    * Parses a TTML time in frame format.
  1136.    *
  1137.    * @param {!shaka.text.TtmlTextParser.RateInfo_} rateInfo
  1138.    * @param {string} text
  1139.    * @return {?number}
  1140.    * @private
  1141.    */
  1142.   static parseFramesTime_(rateInfo, text) {
  1143.     // 75f or 75.5f
  1144.     const results = shaka.text.TtmlTextParser.timeFramesFormat_.exec(text);
  1145.     const frames = Number(results[1]);
  1147.     return frames / rateInfo.frameRate;
  1148.   }
  1150.   /**
  1151.    * Parses a TTML time in tick format.
  1152.    *
  1153.    * @param {!shaka.text.TtmlTextParser.RateInfo_} rateInfo
  1154.    * @param {string} text
  1155.    * @return {?number}
  1156.    * @private
  1157.    */
  1158.   static parseTickTime_(rateInfo, text) {
  1159.     // 50t or 50.5t
  1160.     const results = shaka.text.TtmlTextParser.timeTickFormat_.exec(text);
  1161.     const ticks = Number(results[1]);
  1163.     return ticks / rateInfo.tickRate;
  1164.   }
  1166.   /**
  1167.    * Parses a TTML colon formatted time containing frames.
  1168.    *
  1169.    * @param {!shaka.text.TtmlTextParser.RateInfo_} rateInfo
  1170.    * @param {string} text
  1171.    * @return {?number}
  1172.    * @private
  1173.    */
  1174.   static parseColonTimeWithFrames_(rateInfo, text) {
  1175.     // 01:02:43:07 ('07' is frames) or 01:02:43:07.1 (subframes)
  1176.     const results = shaka.text.TtmlTextParser.timeColonFormatFrames_.exec(text);
  1178.     const hours = Number(results[1]);
  1179.     const minutes = Number(results[2]);
  1180.     let seconds = Number(results[3]);
  1181.     let frames = Number(results[4]);
  1182.     const subframes = Number(results[5]) || 0;
  1184.     frames += subframes / rateInfo.subFrameRate;
  1185.     seconds += frames / rateInfo.frameRate;
  1187.     return seconds + (minutes * 60) + (hours * 3600);
  1188.   }
  1190.   /**
  1191.    * Parses a TTML time with a given regex. Expects regex to be some
  1192.    * sort of a time-matcher to match hours, minutes, seconds and milliseconds
  1193.    *
  1194.    * @param {!RegExp} regex
  1195.    * @param {string} text
  1196.    * @return {?number}
  1197.    * @private
  1198.    */
  1199.   static parseTimeFromRegex_(regex, text) {
  1200.     const results = regex.exec(text);
  1201.     if (results == null || results[0] == '') {
  1202.       return null;
  1203.     }
  1204.     // This capture is optional, but will still be in the array as undefined,
  1205.     // in which case it is 0.
  1206.     const hours = Number(results[1]) || 0;
  1207.     const minutes = Number(results[2]) || 0;
  1208.     const seconds = Number(results[3]) || 0;
  1209.     const milliseconds = Number(results[4]) || 0;
  1211.     return (milliseconds / 1000) + seconds + (minutes * 60) + (hours * 3600);
  1212.   }
  1214.   /**
  1215.    * If ttp:cellResolution provided returns cell resolution info
  1216.    * with number of columns and rows into which the Root Container
  1217.    * Region area is divided
  1218.    *
  1219.    * @param {?string} cellResolution
  1220.    * @return {?{columns: number, rows: number}}
  1221.    * @private
  1222.    */
  1223.   static getCellResolution_(cellResolution) {
  1224.     if (!cellResolution) {
  1225.       return null;
  1226.     }
  1227.     const matches = /^(\d+) (\d+)$/.exec(cellResolution);
  1229.     if (!matches) {
  1230.       return null;
  1231.     }
  1233.     const columns = parseInt(matches[1], 10);
  1234.     const rows = parseInt(matches[2], 10);
  1236.     return {columns, rows};
  1237.   }
  1238. };
  1240. /**
  1241.  * @summary
  1242.  * Contains information about frame/subframe rate
  1243.  * and frame rate multiplier for time in frame format.
  1244.  *
  1245.  * @example 01:02:03:04(4 frames) or 01:02:03:04.1(4 frames, 1 subframe)
  1246.  * @private
  1247.  */
  1248. shaka.text.TtmlTextParser.RateInfo_ = class {
  1249.   /**
  1250.    * @param {?string} frameRate
  1251.    * @param {?string} subFrameRate
  1252.    * @param {?string} frameRateMultiplier
  1253.    * @param {?string} tickRate
  1254.    */
  1255.   constructor(frameRate, subFrameRate, frameRateMultiplier, tickRate) {
  1256.     /**
  1257.      * @type {number}
  1258.      */
  1259.     this.frameRate = Number(frameRate) || 30;
  1261.     /**
  1262.      * @type {number}
  1263.      */
  1264.     this.subFrameRate = Number(subFrameRate) || 1;
  1266.     /**
  1267.      * @type {number}
  1268.      */
  1269.     this.tickRate = Number(tickRate);
  1270.     if (this.tickRate == 0) {
  1271.       if (frameRate) {
  1272.         this.tickRate = this.frameRate * this.subFrameRate;
  1273.       } else {
  1274.         this.tickRate = 1;
  1275.       }
  1276.     }
  1278.     if (frameRateMultiplier) {
  1279.       const multiplierResults = /^(\d+) (\d+)$/g.exec(frameRateMultiplier);
  1280.       if (multiplierResults) {
  1281.         const numerator = Number(multiplierResults[1]);
  1282.         const denominator = Number(multiplierResults[2]);
  1283.         const multiplierNum = numerator / denominator;
  1284.         this.frameRate *= multiplierNum;
  1285.       }
  1286.     }
  1287.   }
  1288. };
  1290. /**
  1291.  * @const
  1292.  * @private {!RegExp}
  1293.  * @example 50.17% 10%
  1294.  */
  1295. shaka.text.TtmlTextParser.percentValues_ =
  1296.     /^(\d{1,2}(?:\.\d+)?|100(?:\.0+)?)% (\d{1,2}(?:\.\d+)?|100(?:\.0+)?)%$/;
  1298. /**
  1299.  * @const
  1300.  * @private {!RegExp}
  1301.  * @example 0.6% 90%
  1302.  */
  1303. shaka.text.TtmlTextParser.percentValue_ = /^(\d{1,2}(?:\.\d+)?|100)%$/;
  1305. /**
  1306.  * @const
  1307.  * @private {!RegExp}
  1308.  * @example 100px, 8em, 0.80c
  1309.  */
  1310. shaka.text.TtmlTextParser.unitValues_ = /^(\d+px|\d+em|\d*\.?\d+c)$/;
  1312. /**
  1313.  * @const
  1314.  * @private {!RegExp}
  1315.  * @example 100px
  1316.  */
  1317. shaka.text.TtmlTextParser.pixelValues_ = /^(\d+)px (\d+)px$/;
  1319. /**
  1320.  * @const
  1321.  * @private {!RegExp}
  1322.  * @example 00:00:40:07 (7 frames) or 00:00:40:07.1 (7 frames, 1 subframe)
  1323.  */
  1324. shaka.text.TtmlTextParser.timeColonFormatFrames_ =
  1325.     /^(\d{2,}):(\d{2}):(\d{2}):(\d{2})\.?(\d+)?$/;
  1327. /**
  1328.  * @const
  1329.  * @private {!RegExp}
  1330.  * @example 00:00:40 or 00:40
  1331.  */
  1332. shaka.text.TtmlTextParser.timeColonFormat_ = /^(?:(\d{2,}):)?(\d{2}):(\d{2})$/;
  1334. /**
  1335.  * @const
  1336.  * @private {!RegExp}
  1337.  * @example 01:02:43.0345555 or 02:43.03
  1338.  */
  1339. shaka.text.TtmlTextParser.timeColonFormatMilliseconds_ =
  1340.     /^(?:(\d{2,}):)?(\d{2}):(\d{2}\.\d{2,})$/;
  1342. /**
  1343.  * @const
  1344.  * @private {!RegExp}
  1345.  * @example 75f or 75.5f
  1346.  */
  1347. shaka.text.TtmlTextParser.timeFramesFormat_ = /^(\d*(?:\.\d*)?)f$/;
  1349. /**
  1350.  * @const
  1351.  * @private {!RegExp}
  1352.  * @example 50t or 50.5t
  1353.  */
  1354. shaka.text.TtmlTextParser.timeTickFormat_ = /^(\d*(?:\.\d*)?)t$/;
  1356. /**
  1357.  * @const
  1358.  * @private {!RegExp}
  1359.  * @example 3.45h, 3m or 4.20s
  1360.  */
  1361. shaka.text.TtmlTextParser.timeHMSFormat_ =
  1362.     new RegExp(['^(?:(\\d*(?:\\.\\d*)?)h)?',
  1363.       '(?:(\\d*(?:\\.\\d*)?)m)?',
  1364.       '(?:(\\d*(?:\\.\\d*)?)s)?',
  1365.       '(?:(\\d*(?:\\.\\d*)?)ms)?$'].join(''));
  1367. /**
  1368.  * @const
  1369.  * @private {!Object.<string, shaka.text.Cue.lineAlign>}
  1370.  */
  1371. shaka.text.TtmlTextParser.textAlignToLineAlign_ = {
  1372.   'left': shaka.text.Cue.lineAlign.START,
  1373.   'center': shaka.text.Cue.lineAlign.CENTER,
  1374.   'right': shaka.text.Cue.lineAlign.END,
  1375.   'start': shaka.text.Cue.lineAlign.START,
  1376.   'end': shaka.text.Cue.lineAlign.END,
  1377. };
  1379. /**
  1380.  * @const
  1381.  * @private {!Object.<string, shaka.text.Cue.positionAlign>}
  1382.  */
  1383. shaka.text.TtmlTextParser.textAlignToPositionAlign_ = {
  1384.   'left': shaka.text.Cue.positionAlign.LEFT,
  1385.   'center': shaka.text.Cue.positionAlign.CENTER,
  1386.   'right': shaka.text.Cue.positionAlign.RIGHT,
  1387. };
  1389. /**
  1390.  * The namespace URL for TTML parameters.  Can be assigned any name in the TTML
  1391.  * document, not just "ttp:", so we use this with getAttributeNS() to ensure
  1392.  * that we support arbitrary namespace names.
  1393.  *
  1394.  * @const {!Array.<string>}
  1395.  * @private
  1396.  */
  1397. shaka.text.TtmlTextParser.parameterNs_ = [
  1398.   'http://www.w3.org/ns/ttml#parameter',
  1399.   'http://www.w3.org/2006/10/ttaf1#parameter',
  1400. ];
  1402. /**
  1403.  * The namespace URL for TTML styles.  Can be assigned any name in the TTML
  1404.  * document, not just "tts:", so we use this with getAttributeNS() to ensure
  1405.  * that we support arbitrary namespace names.
  1406.  *
  1407.  * @const {!Array.<string>}
  1408.  * @private
  1409.  */
  1410. shaka.text.TtmlTextParser.styleNs_ = [
  1411.   'http://www.w3.org/ns/ttml#styling',
  1412.   'http://www.w3.org/2006/10/ttaf1#styling',
  1413. ];
  1415. /**
  1416.  * The namespace URL for EBU TTML styles.  Can be assigned any name in the TTML
  1417.  * document, not just "ebutts:", so we use this with getAttributeNS() to ensure
  1418.  * that we support arbitrary namespace names.
  1419.  *
  1420.  * @const {string}
  1421.  * @private
  1422.  */
  1423. shaka.text.TtmlTextParser.styleEbuttsNs_ = 'urn:ebu:tt:style';
  1425. /**
  1426.  * The supported namespace URLs for SMPTE fields.
  1427.  * @const {!Array.<string>}
  1428.  * @private
  1429.  */
  1430. shaka.text.TtmlTextParser.smpteNsList_ = [
  1431.   'http://www.smpte-ra.org/schemas/2052-1/2010/smpte-tt',
  1432.   'http://www.smpte-ra.org/schemas/2052-1/2013/smpte-tt',
  1433. ];
  1435. shaka.text.TextEngine.registerParser(
  1436.     'application/ttml+xml', () => new shaka.text.TtmlTextParser());