shaka-player
Version:
DASH/EME video player library
1,247 lines (1,105 loc) • 38.8 kB
JavaScript
/*! @license
* Shaka Player
* Copyright 2016 Google LLC
* SPDX-License-Identifier: Apache-2.0
*/
goog.provide('shaka.text.TtmlTextParser');
goog.require('goog.asserts');
goog.require('shaka.log');
goog.require('shaka.text.Cue');
goog.require('shaka.text.CueRegion');
goog.require('shaka.text.TextEngine');
goog.require('shaka.util.ArrayUtils');
goog.require('shaka.util.Error');
goog.require('shaka.util.StringUtils');
goog.require('shaka.util.XmlUtils');
/**
* @implements {shaka.extern.TextParser}
* @export
*/
shaka.text.TtmlTextParser = class {
/**
* @override
* @export
*/
parseInit(data) {
goog.asserts.assert(false, 'TTML does not have init segments');
}
/**
* @override
* @export
*/
parseMedia(data, time) {
const TtmlTextParser = shaka.text.TtmlTextParser;
const XmlUtils = shaka.util.XmlUtils;
const ttpNs = TtmlTextParser.parameterNs_;
const ttsNs = TtmlTextParser.styleNs_;
const str = shaka.util.StringUtils.fromUTF8(data);
const ret = [];
const parser = new DOMParser();
let xml = null;
// dont try to parse empty string as
// DOMParser will not throw error but return an errored xml
if (str == '') {
return ret;
}
try {
xml = parser.parseFromString(str, 'text/xml');
} catch (exception) {
throw new shaka.util.Error(
shaka.util.Error.Severity.CRITICAL,
shaka.util.Error.Category.TEXT,
shaka.util.Error.Code.INVALID_XML,
'Failed to parse TTML.');
}
if (xml) {
const parserError = xml.getElementsByTagName('parsererror')[0];
if (parserError) {
throw new shaka.util.Error(
shaka.util.Error.Severity.CRITICAL,
shaka.util.Error.Category.TEXT,
shaka.util.Error.Code.INVALID_XML,
parserError.textContent);
}
// Try to get the framerate, subFrameRate and frameRateMultiplier
// if applicable
let frameRate = null;
let subFrameRate = null;
let frameRateMultiplier = null;
let tickRate = null;
let spaceStyle = null;
let extent = null;
let cellResolution = null;
const tts = xml.getElementsByTagName('tt');
const tt = tts[0];
// TTML should always have tt element.
if (!tt) {
throw new shaka.util.Error(
shaka.util.Error.Severity.CRITICAL,
shaka.util.Error.Category.TEXT,
shaka.util.Error.Code.INVALID_XML,
'TTML does not contain <tt> tag.');
} else {
frameRate = XmlUtils.getAttributeNS(tt, ttpNs, 'frameRate');
subFrameRate = XmlUtils.getAttributeNS(tt, ttpNs, 'subFrameRate');
frameRateMultiplier =
XmlUtils.getAttributeNS(tt, ttpNs, 'frameRateMultiplier');
tickRate = XmlUtils.getAttributeNS(tt, ttpNs, 'tickRate');
cellResolution = XmlUtils.getAttributeNS(tt, ttpNs, 'cellResolution');
spaceStyle = tt.getAttribute('xml:space') || 'default';
extent = XmlUtils.getAttributeNS(tt, ttsNs, 'extent');
}
if (spaceStyle != 'default' && spaceStyle != 'preserve') {
throw new shaka.util.Error(
shaka.util.Error.Severity.CRITICAL,
shaka.util.Error.Category.TEXT,
shaka.util.Error.Code.INVALID_XML,
'Invalid xml:space value: ' + spaceStyle);
}
const whitespaceTrim = spaceStyle == 'default';
const rateInfo = new TtmlTextParser.RateInfo_(
frameRate, subFrameRate, frameRateMultiplier, tickRate);
const cellResolutionInfo =
TtmlTextParser.getCellResolution_(cellResolution);
const metadataElements = TtmlTextParser.getLeafNodes_(
tt.getElementsByTagName('metadata')[0]);
const styles = TtmlTextParser.getLeafNodes_(
tt.getElementsByTagName('styling')[0]);
const regionElements = TtmlTextParser.getLeafNodes_(
tt.getElementsByTagName('layout')[0]);
const cueRegions = [];
for (const region of regionElements) {
const cueRegion =
TtmlTextParser.parseCueRegion_(region, styles, extent);
if (cueRegion) {
cueRegions.push(cueRegion);
}
}
const textNodes = TtmlTextParser.getLeafCues_(
tt.getElementsByTagName('body')[0]);
for (const node of textNodes) {
const cue = TtmlTextParser.parseCue_(
node, time.periodStart, rateInfo, metadataElements, styles,
regionElements, cueRegions, whitespaceTrim, false,
cellResolutionInfo);
if (cue) {
ret.push(cue);
}
}
}
return ret;
}
/**
* Gets the leaf nodes of the xml node tree. Ignores the text, br elements
* and the spans positioned inside paragraphs
*
* @param {Element} element
* @return {!Array.<!Element>}
* @private
*/
static getLeafNodes_(element) {
let result = [];
if (!element) {
return result;
}
for (const node of element.childNodes) {
if (
node.nodeType == Node.ELEMENT_NODE &&
node.nodeName !== 'br'
) {
// Get the leaves the child might contain.
goog.asserts.assert(node instanceof Element,
'Node should be Element!');
const leafChildren = shaka.text.TtmlTextParser.getLeafNodes_(
/** @type {Element} */(node));
goog.asserts.assert(leafChildren.length > 0,
'Only a null Element should return no leaves!');
result = result.concat(leafChildren);
}
}
// if no result at this point, the element itself must be a leaf.
if (!result.length) {
result.push(element);
}
return result;
}
/**
* Get the leaf nodes that can act as cues
* (at least begin attribute)
*
* @param {Element} element
* @return {!Array.<!Element>}
* @private
*/
static getLeafCues_(element) {
if (!element) {
return [];
}
let ret = [];
// Recursively find any child elements that have a 'begin' attribute.
for (const child of element.childNodes) {
if (child instanceof Element) {
if (child.hasAttribute('begin')) {
ret.push(child);
} else {
ret = ret.concat(shaka.text.TtmlTextParser.getLeafCues_(child));
}
}
}
return ret;
}
/**
* Trims and removes multiple spaces from a string
*
* @param {Element} element
* @param {boolean} whitespaceTrim
* @return {string}
* @private
*/
static sanitizeTextContent_(element, whitespaceTrim) {
let payload = '';
for (const node of element.childNodes) {
if (node.nodeName == 'br' && element.childNodes[0] !== node) {
payload += '\n';
} else if (node.childNodes && node.childNodes.length > 0) {
payload += shaka.text.TtmlTextParser.sanitizeTextContent_(
/** @type {!Element} */ (node),
whitespaceTrim
);
} else if (whitespaceTrim) {
// Trim leading and trailing whitespace.
let trimmed = node.textContent.trim();
// Collapse multiple spaces into one.
trimmed = trimmed.replace(/\s+/g, ' ');
payload += trimmed;
} else {
payload += node.textContent;
}
}
return payload;
}
/**
* Parses an Element into a TextTrackCue or VTTCue.
*
* @param {!Element} cueElement
* @param {number} offset
* @param {!shaka.text.TtmlTextParser.RateInfo_} rateInfo
* @param {!Array.<!Element>} metadataElements
* @param {!Array.<!Element>} styles
* @param {!Array.<!Element>} regionElements
* @param {!Array.<!shaka.text.CueRegion>} cueRegions
* @param {boolean} whitespaceTrim
* @param {boolean} isNested
* @param {?{columns: number, rows: number}} cellResolution
* @return {shaka.text.Cue}
* @private
*/
static parseCue_(
cueElement, offset, rateInfo, metadataElements, styles, regionElements,
cueRegions, whitespaceTrim, isNested, cellResolution) {
if (isNested && cueElement.nodeName == 'br') {
const cue = new shaka.text.Cue(0, 0, '');
cue.spacer = true;
return cue;
}
const isTextContentEmpty = /^[\s\n]*$/.test(cueElement.textContent);
const hasNoTimeAttributes = cueElement.nodeType == Node.ELEMENT_NODE &&
!cueElement.hasAttribute('begin') &&
!cueElement.hasAttribute('end');
if (
cueElement.nodeType != Node.ELEMENT_NODE ||
/* Disregards empty elements without time attributes nor content
* <p begin="..." smpte:backgroundImage="..." /> will go through,
* as some information could be holded by its attributes
* <p />, <div></div> won't,
* as they don't have means to be displayed into a playback sequence
*/
(hasNoTimeAttributes && isTextContentEmpty) ||
/*
* Let nested cue without time attributes through:
* time attributes are holded by its parent
*/
(hasNoTimeAttributes && !isNested)
) {
return null;
}
const spaceStyle = cueElement.getAttribute('xml:space') ||
(whitespaceTrim ? 'default' : 'preserve');
const localWhitespaceTrim = spaceStyle == 'default';
// Get time.
let start = shaka.text.TtmlTextParser.parseTime_(
cueElement.getAttribute('begin'), rateInfo);
let end = shaka.text.TtmlTextParser.parseTime_(
cueElement.getAttribute('end'), rateInfo);
const duration = shaka.text.TtmlTextParser.parseTime_(
cueElement.getAttribute('dur'), rateInfo);
if (end == null && duration != null) {
end = start + duration;
}
if (!isNested && (start == null || end == null)) {
throw new shaka.util.Error(
shaka.util.Error.Severity.CRITICAL,
shaka.util.Error.Category.TEXT,
shaka.util.Error.Code.INVALID_TEXT_CUE);
}
if (isNested && start == null) {
start = 0;
} else {
start += offset;
}
if (isNested && end == null) {
end = 0;
} else {
end += offset;
}
let payload = '';
const nestedCues = [];
// If one of the children is a text node with something other than
// whitespace in it, stop going down and write the payload.
const isNonEmptyText = (node) => {
// In this regex, "\S+" means "one or more non-whitespace characters".
return node.nodeType == Node.TEXT_NODE &&
/\S+/.test(node.textContent);
};
if (Array.from(cueElement.childNodes).some(isNonEmptyText)) {
payload = shaka.text.TtmlTextParser.sanitizeTextContent_(
cueElement,
localWhitespaceTrim);
} else {
for (const childNode of cueElement.childNodes) {
const nestedCue = shaka.text.TtmlTextParser.parseCue_(
/** @type {!Element} */ (childNode),
offset,
rateInfo,
metadataElements,
styles,
regionElements,
cueRegions,
localWhitespaceTrim,
/* isNested= */ true,
cellResolution,
);
if (nestedCue) {
// Set the start time and end time for the nested cues.
nestedCue.startTime = nestedCue.startTime || start;
nestedCue.endTime = nestedCue.endTime || end;
nestedCues.push(nestedCue);
}
}
}
const cue = new shaka.text.Cue(start, end, payload);
cue.nestedCues = nestedCues;
if (cellResolution) {
cue.cellResolution = cellResolution;
}
// Get other properties if available.
const regionElement = shaka.text.TtmlTextParser.getElementsFromCollection_(
cueElement, 'region', regionElements, /* prefix= */ '')[0];
if (regionElement && regionElement.getAttribute('xml:id')) {
const regionId = regionElement.getAttribute('xml:id');
cue.region = cueRegions.filter((region) => region.id == regionId)[0];
}
const imageElement = shaka.text.TtmlTextParser.getElementsFromCollection_(
cueElement, 'backgroundImage', metadataElements, '#',
shaka.text.TtmlTextParser.smpteNs_)[0];
shaka.text.TtmlTextParser.addStyle_(
cue,
cueElement,
regionElement,
imageElement,
styles);
return cue;
}
/**
* Parses an Element into a TextTrackCue or VTTCue.
*
* @param {!Element} regionElement
* @param {!Array.<!Element>} styles Defined in the top of tt element and
* used principally for images.
* @param {?string} globalExtent
* @return {shaka.text.CueRegion}
* @private
*/
static parseCueRegion_(regionElement, styles, globalExtent) {
const TtmlTextParser = shaka.text.TtmlTextParser;
const region = new shaka.text.CueRegion();
const id = regionElement.getAttribute('xml:id');
if (!id) {
shaka.log.warning('TtmlTextParser parser encountered a region with ' +
'no id. Region will be ignored.');
return null;
}
region.id = id;
let globalResults = null;
if (globalExtent) {
globalResults = TtmlTextParser.percentValues_.exec(globalExtent) ||
TtmlTextParser.pixelValues_.exec(globalExtent);
}
const globalWidth = globalResults ? Number(globalResults[1]) : null;
const globalHeight = globalResults ? Number(globalResults[2]) : null;
let results = null;
let percentage = null;
const extent = TtmlTextParser.getStyleAttributeFromRegion_(
regionElement, styles, 'extent');
if (extent) {
percentage = TtmlTextParser.percentValues_.exec(extent);
results = percentage || TtmlTextParser.pixelValues_.exec(extent);
if (results != null) {
if (globalWidth != null) {
region.width = Number(results[1]) * 100 / globalWidth;
} else {
region.width = Number(results[1]);
}
if (globalHeight != null) {
region.height = Number(results[2]) * 100 / globalHeight;
} else {
region.height = Number(results[2]);
}
region.widthUnits = percentage || globalWidth != null ?
shaka.text.CueRegion.units.PERCENTAGE :
shaka.text.CueRegion.units.PX;
region.heightUnits = percentage || globalHeight != null ?
shaka.text.CueRegion.units.PERCENTAGE :
shaka.text.CueRegion.units.PX;
}
}
const origin = TtmlTextParser.getStyleAttributeFromRegion_(
regionElement, styles, 'origin');
if (origin) {
percentage = TtmlTextParser.percentValues_.exec(origin);
results = percentage || TtmlTextParser.pixelValues_.exec(origin);
if (results != null) {
if (globalWidth != null) {
region.viewportAnchorX = Number(results[1]) * 100 / globalWidth;
} else {
region.viewportAnchorX = Number(results[1]);
}
if (globalHeight != null) {
region.viewportAnchorY = Number(results[2]) * 100 / globalHeight;
} else {
region.viewportAnchorY = Number(results[2]);
}
region.viewportAnchorUnits = percentage || globalWidth != null ?
shaka.text.CueRegion.units.PERCENTAGE :
shaka.text.CueRegion.units.PX;
}
}
return region;
}
/**
* Adds applicable style properties to a cue.
*
* @param {!shaka.text.Cue} cue
* @param {!Element} cueElement
* @param {Element} region
* @param {Element} imageElement
* @param {!Array.<!Element>} styles
* @private
*/
static addStyle_(cue, cueElement, region, imageElement, styles) {
const TtmlTextParser = shaka.text.TtmlTextParser;
const Cue = shaka.text.Cue;
const direction = TtmlTextParser.getStyleAttribute_(
cueElement, region, styles, 'direction');
if (direction == 'rtl') {
cue.direction = Cue.direction.HORIZONTAL_RIGHT_TO_LEFT;
}
// Direction attribute specifies one-dimentional writing direction
// (left to right or right to left). Writing mode specifies that
// plus whether text is vertical or horizontal.
// They should not contradict each other. If they do, we give
// preference to writing mode.
const writingMode = TtmlTextParser.getStyleAttribute_(
cueElement, region, styles, 'writingMode');
// Set cue's direction if the text is horizontal, and cue's writingMode if
// it's vertical.
if (writingMode == 'tb' || writingMode == 'tblr') {
cue.writingMode = Cue.writingMode.VERTICAL_LEFT_TO_RIGHT;
} else if (writingMode == 'tbrl') {
cue.writingMode = Cue.writingMode.VERTICAL_RIGHT_TO_LEFT;
} else if (writingMode == 'rltb' || writingMode == 'rl') {
cue.direction = Cue.direction.HORIZONTAL_RIGHT_TO_LEFT;
} else if (writingMode) {
cue.direction = Cue.direction.HORIZONTAL_LEFT_TO_RIGHT;
}
const align = TtmlTextParser.getStyleAttribute_(
cueElement, region, styles, 'textAlign');
if (align) {
cue.positionAlign = TtmlTextParser.textAlignToPositionAlign_[align];
cue.lineAlign = TtmlTextParser.textAlignToLineAlign_[align];
goog.asserts.assert(align.toUpperCase() in Cue.textAlign,
align.toUpperCase() +
' Should be in Cue.textAlign values!');
cue.textAlign = Cue.textAlign[align.toUpperCase()];
} else {
// Default value is START: https://bit.ly/32OGmvo
cue.textAlign = Cue.textAlign.START;
}
const displayAlign = TtmlTextParser.getStyleAttribute_(
cueElement, region, styles, 'displayAlign');
if (displayAlign) {
goog.asserts.assert(displayAlign.toUpperCase() in Cue.displayAlign,
displayAlign.toUpperCase() +
' Should be in Cue.displayAlign values!');
cue.displayAlign = Cue.displayAlign[displayAlign.toUpperCase()];
}
const color = TtmlTextParser.getStyleAttribute_(
cueElement, region, styles, 'color');
if (color) {
cue.color = color;
}
const backgroundColor = TtmlTextParser.getStyleAttribute_(
cueElement, region, styles, 'backgroundColor');
if (backgroundColor) {
cue.backgroundColor = backgroundColor;
}
const border = TtmlTextParser.getStyleAttribute_(
cueElement, region, styles, 'border');
if (border) {
cue.border = border;
}
const fontFamily = TtmlTextParser.getStyleAttribute_(
cueElement, region, styles, 'fontFamily');
if (fontFamily) {
cue.fontFamily = fontFamily;
}
const fontWeight = TtmlTextParser.getStyleAttribute_(
cueElement, region, styles, 'fontWeight');
if (fontWeight && fontWeight == 'bold') {
cue.fontWeight = Cue.fontWeight.BOLD;
}
const wrapOption = TtmlTextParser.getStyleAttribute_(
cueElement, region, styles, 'wrapOption');
if (wrapOption && wrapOption == 'noWrap') {
cue.wrapLine = false;
}
const lineHeight = TtmlTextParser.getStyleAttribute_(
cueElement, region, styles, 'lineHeight');
if (lineHeight && lineHeight.match(TtmlTextParser.unitValues_)) {
cue.lineHeight = lineHeight;
}
const fontSize = TtmlTextParser.getStyleAttribute_(
cueElement, region, styles, 'fontSize');
if (fontSize) {
const isValidFontSizeUnit =
fontSize.match(TtmlTextParser.unitValues_) ||
fontSize.match(TtmlTextParser.percentValue_);
if (isValidFontSizeUnit) {
cue.fontSize = fontSize;
}
}
const fontStyle = TtmlTextParser.getStyleAttribute_(
cueElement, region, styles, 'fontStyle');
if (fontStyle) {
goog.asserts.assert(fontStyle.toUpperCase() in Cue.fontStyle,
fontStyle.toUpperCase() +
' Should be in Cue.fontStyle values!');
cue.fontStyle = Cue.fontStyle[fontStyle.toUpperCase()];
}
if (imageElement) {
// According to the spec, we should use imageType (camelCase), but
// historically we have checked for imagetype (lowercase).
// This was the case since background image support was first introduced
// in PR #1859, in April 2019, and first released in v2.5.0.
// Now we check for both, although only imageType (camelCase) is to spec.
const backgroundImageType =
imageElement.getAttribute('imageType') ||
imageElement.getAttribute('imagetype');
const backgroundImageEncoding = imageElement.getAttribute('encoding');
const backgroundImageData = imageElement.textContent.trim();
if (backgroundImageType == 'PNG' &&
backgroundImageEncoding == 'Base64' &&
backgroundImageData) {
cue.backgroundImage = 'data:image/png;base64,' + backgroundImageData;
}
}
const letterSpacing = TtmlTextParser.getStyleAttribute_(
cueElement, region, styles, 'letterSpacing');
if (letterSpacing && letterSpacing.match(TtmlTextParser.unitValues_)) {
cue.letterSpacing = letterSpacing;
}
const linePadding = TtmlTextParser.getStyleAttribute_(
cueElement, region, styles, 'linePadding');
if (linePadding && linePadding.match(TtmlTextParser.unitValues_)) {
cue.linePadding = linePadding;
}
const opacity = TtmlTextParser.getStyleAttribute_(
cueElement, region, styles, 'opacity');
if (opacity) {
cue.opacity = parseFloat(opacity);
}
// Text decoration is an array of values which can come both from the
// element's style or be inherited from elements' parent nodes. All of those
// values should be applied as long as they don't contradict each other. If
// they do, elements' own style gets preference.
const textDecorationRegion = TtmlTextParser.getStyleAttributeFromRegion_(
region, styles, 'textDecoration');
if (textDecorationRegion) {
TtmlTextParser.addTextDecoration_(cue, textDecorationRegion);
}
const textDecorationElement = TtmlTextParser.getStyleAttributeFromElement_(
cueElement, styles, 'textDecoration');
if (textDecorationElement) {
TtmlTextParser.addTextDecoration_(cue, textDecorationElement);
}
}
/**
* Parses text decoration values and adds/removes them to/from the cue.
*
* @param {!shaka.text.Cue} cue
* @param {string} decoration
* @private
*/
static addTextDecoration_(cue, decoration) {
const Cue = shaka.text.Cue;
for (const value of decoration.split(' ')) {
switch (value) {
case 'underline':
if (!cue.textDecoration.includes(Cue.textDecoration.UNDERLINE)) {
cue.textDecoration.push(Cue.textDecoration.UNDERLINE);
}
break;
case 'noUnderline':
if (cue.textDecoration.includes(Cue.textDecoration.UNDERLINE)) {
shaka.util.ArrayUtils.remove(cue.textDecoration,
Cue.textDecoration.UNDERLINE);
}
break;
case 'lineThrough':
if (!cue.textDecoration.includes(Cue.textDecoration.LINE_THROUGH)) {
cue.textDecoration.push(Cue.textDecoration.LINE_THROUGH);
}
break;
case 'noLineThrough':
if (cue.textDecoration.includes(Cue.textDecoration.LINE_THROUGH)) {
shaka.util.ArrayUtils.remove(cue.textDecoration,
Cue.textDecoration.LINE_THROUGH);
}
break;
case 'overline':
if (!cue.textDecoration.includes(Cue.textDecoration.OVERLINE)) {
cue.textDecoration.push(Cue.textDecoration.OVERLINE);
}
break;
case 'noOverline':
if (cue.textDecoration.includes(Cue.textDecoration.OVERLINE)) {
shaka.util.ArrayUtils.remove(cue.textDecoration,
Cue.textDecoration.OVERLINE);
}
break;
}
}
}
/**
* Finds a specified attribute on either the original cue element or its
* associated region and returns the value if the attribute was found.
*
* @param {!Element} cueElement
* @param {Element} region
* @param {!Array.<!Element>} styles
* @param {string} attribute
* @return {?string}
* @private
*/
static getStyleAttribute_(cueElement, region, styles, attribute) {
// An attribute can be specified on region level or in a styling block
// associated with the region or original element.
const TtmlTextParser = shaka.text.TtmlTextParser;
const attr = TtmlTextParser.getStyleAttributeFromElement_(
cueElement, styles, attribute);
if (attr) {
return attr;
}
return TtmlTextParser.getStyleAttributeFromRegion_(
region, styles, attribute);
}
/**
* Finds a specified attribute on the element's associated region
* and returns the value if the attribute was found.
*
* @param {Element} region
* @param {!Array.<!Element>} styles
* @param {string} attribute
* @return {?string}
* @private
*/
static getStyleAttributeFromRegion_(region, styles, attribute) {
const XmlUtils = shaka.util.XmlUtils;
const ttsNs = shaka.text.TtmlTextParser.styleNs_;
if (!region) {
return null;
}
const regionChildren = shaka.text.TtmlTextParser.getLeafNodes_(region);
for (const child of regionChildren) {
const attr = XmlUtils.getAttributeNS(child, ttsNs, attribute);
if (attr) {
return attr;
}
}
return shaka.text.TtmlTextParser.getInheritedStyleAttribute_(
region, styles, attribute);
}
/**
* Finds a specified attribute on the cue element and returns the value
* if the attribute was found.
*
* @param {!Element} cueElement
* @param {!Array.<!Element>} styles
* @param {string} attribute
* @return {?string}
* @private
*/
static getStyleAttributeFromElement_(cueElement, styles, attribute) {
const XmlUtils = shaka.util.XmlUtils;
const ttsNs = shaka.text.TtmlTextParser.styleNs_;
// Styling on elements should take precedence
// over the main styling attributes
const elementAttribute = XmlUtils.getAttributeNS(
cueElement,
ttsNs,
attribute);
if (elementAttribute) {
return elementAttribute;
}
return shaka.text.TtmlTextParser.getInheritedStyleAttribute_(
cueElement, styles, attribute);
}
/**
* Finds a specified attribute on an element's styles and the styles those
* styles inherit from.
*
* @param {!Element} element
* @param {!Array.<!Element>} styles
* @param {string} attribute
* @return {?string}
* @private
*/
static getInheritedStyleAttribute_(element, styles, attribute) {
const XmlUtils = shaka.util.XmlUtils;
const ttsNs = shaka.text.TtmlTextParser.styleNs_;
const ebuttsNs = shaka.text.TtmlTextParser.styleEbuttsNs_;
const inheritedStyles =
shaka.text.TtmlTextParser.getElementsFromCollection_(
element, 'style', styles, /* prefix= */ '');
let styleValue = null;
// The last value in our styles stack takes the precedence over the others
for (let i = 0; i < inheritedStyles.length; i++) {
// Check ebu namespace first.
let styleAttributeValue = XmlUtils.getAttributeNS(
inheritedStyles[i],
ebuttsNs,
attribute);
if (!styleAttributeValue) {
// Fall back to tts namespace.
styleAttributeValue = XmlUtils.getAttributeNS(
inheritedStyles[i],
ttsNs,
attribute);
}
if (!styleAttributeValue) {
// Next, check inheritance.
// Styles can inherit from other styles, so traverse up that chain.
styleAttributeValue =
shaka.text.TtmlTextParser.getStyleAttributeFromElement_(
inheritedStyles[i], styles, attribute);
}
if (styleAttributeValue) {
styleValue = styleAttributeValue;
}
}
return styleValue;
}
/**
* Selects items from |collection| whose id matches |attributeName|
* from |element|.
*
* @param {Element} element
* @param {string} attributeName
* @param {!Array.<Element>} collection
* @param {string} prefixName
* @param {string=} nsName
* @return {!Array.<!Element>}
* @private
*/
static getElementsFromCollection_(
element, attributeName, collection, prefixName, nsName) {
const items = [];
if (!element || collection.length < 1) {
return items;
}
const attributeValue = shaka.text.TtmlTextParser.getInheritedAttribute_(
element, attributeName, nsName);
if (attributeValue) {
// There could be multiple items in one attribute
// <span style="style1 style2">A cue</span>
const itemNames = attributeValue.split(' ');
for (const name of itemNames) {
for (const item of collection) {
if ((prefixName + item.getAttribute('xml:id')) == name) {
items.push(item);
break;
}
}
}
}
return items;
}
/**
* Traverses upwards from a given node until a given attribute is found.
*
* @param {!Element} element
* @param {string} attributeName
* @param {string=} nsName
* @return {?string}
* @private
*/
static getInheritedAttribute_(element, attributeName, nsName) {
let ret = null;
const XmlUtils = shaka.util.XmlUtils;
while (element) {
ret = nsName ? XmlUtils.getAttributeNS(element, nsName, attributeName)
: element.getAttribute(attributeName);
if (ret) {
break;
}
// Element.parentNode can lead to XMLDocument, which is not an Element and
// has no getAttribute().
const parentNode = element.parentNode;
if (parentNode instanceof Element) {
element = parentNode;
} else {
break;
}
}
return ret;
}
/**
* Parses a TTML time from the given word.
*
* @param {string} text
* @param {!shaka.text.TtmlTextParser.RateInfo_} rateInfo
* @return {?number}
* @private
*/
static parseTime_(text, rateInfo) {
let ret = null;
const TtmlTextParser = shaka.text.TtmlTextParser;
if (TtmlTextParser.timeColonFormatFrames_.test(text)) {
ret = TtmlTextParser.parseColonTimeWithFrames_(rateInfo, text);
} else if (TtmlTextParser.timeColonFormat_.test(text)) {
ret = TtmlTextParser.parseTimeFromRegex_(
TtmlTextParser.timeColonFormat_, text);
} else if (TtmlTextParser.timeColonFormatMilliseconds_.test(text)) {
ret = TtmlTextParser.parseTimeFromRegex_(
TtmlTextParser.timeColonFormatMilliseconds_, text);
} else if (TtmlTextParser.timeFramesFormat_.test(text)) {
ret = TtmlTextParser.parseFramesTime_(rateInfo, text);
} else if (TtmlTextParser.timeTickFormat_.test(text)) {
ret = TtmlTextParser.parseTickTime_(rateInfo, text);
} else if (TtmlTextParser.timeHMSFormat_.test(text)) {
ret = TtmlTextParser.parseTimeFromRegex_(
TtmlTextParser.timeHMSFormat_, text);
}
return ret;
}
/**
* Parses a TTML time in frame format.
*
* @param {!shaka.text.TtmlTextParser.RateInfo_} rateInfo
* @param {string} text
* @return {?number}
* @private
*/
static parseFramesTime_(rateInfo, text) {
// 75f or 75.5f
const results = shaka.text.TtmlTextParser.timeFramesFormat_.exec(text);
const frames = Number(results[1]);
return frames / rateInfo.frameRate;
}
/**
* Parses a TTML time in tick format.
*
* @param {!shaka.text.TtmlTextParser.RateInfo_} rateInfo
* @param {string} text
* @return {?number}
* @private
*/
static parseTickTime_(rateInfo, text) {
// 50t or 50.5t
const results = shaka.text.TtmlTextParser.timeTickFormat_.exec(text);
const ticks = Number(results[1]);
return ticks / rateInfo.tickRate;
}
/**
* Parses a TTML colon formatted time containing frames.
*
* @param {!shaka.text.TtmlTextParser.RateInfo_} rateInfo
* @param {string} text
* @return {?number}
* @private
*/
static parseColonTimeWithFrames_(rateInfo, text) {
// 01:02:43:07 ('07' is frames) or 01:02:43:07.1 (subframes)
const results = shaka.text.TtmlTextParser.timeColonFormatFrames_.exec(text);
const hours = Number(results[1]);
const minutes = Number(results[2]);
let seconds = Number(results[3]);
let frames = Number(results[4]);
const subframes = Number(results[5]) || 0;
frames += subframes / rateInfo.subFrameRate;
seconds += frames / rateInfo.frameRate;
return seconds + (minutes * 60) + (hours * 3600);
}
/**
* Parses a TTML time with a given regex. Expects regex to be some
* sort of a time-matcher to match hours, minutes, seconds and milliseconds
*
* @param {!RegExp} regex
* @param {string} text
* @return {?number}
* @private
*/
static parseTimeFromRegex_(regex, text) {
const results = regex.exec(text);
if (results == null || results[0] == '') {
return null;
}
// This capture is optional, but will still be in the array as undefined,
// in which case it is 0.
const hours = Number(results[1]) || 0;
const minutes = Number(results[2]) || 0;
const seconds = Number(results[3]) || 0;
const milliseconds = Number(results[4]) || 0;
return (milliseconds / 1000) + seconds + (minutes * 60) + (hours * 3600);
}
/**
* If ttp:cellResolution provided returns cell resolution info
* with number of columns and rows into which the Root Container
* Region area is divided
*
* @param {?string} cellResolution
* @return {?{columns: number, rows: number}}
* @private
*/
static getCellResolution_(cellResolution) {
if (!cellResolution) {
return null;
}
const matches = /^(\d+) (\d+)$/.exec(cellResolution);
if (!matches) {
return null;
}
const columns = parseInt(matches[1], 10);
const rows = parseInt(matches[2], 10);
return {columns, rows};
}
};
/**
* @summary
* Contains information about frame/subframe rate
* and frame rate multiplier for time in frame format.
*
* @example 01:02:03:04(4 frames) or 01:02:03:04.1(4 frames, 1 subframe)
* @private
*/
shaka.text.TtmlTextParser.RateInfo_ = class {
/**
* @param {?string} frameRate
* @param {?string} subFrameRate
* @param {?string} frameRateMultiplier
* @param {?string} tickRate
*/
constructor(frameRate, subFrameRate, frameRateMultiplier, tickRate) {
/**
* @type {number}
*/
this.frameRate = Number(frameRate) || 30;
/**
* @type {number}
*/
this.subFrameRate = Number(subFrameRate) || 1;
/**
* @type {number}
*/
this.tickRate = Number(tickRate);
if (this.tickRate == 0) {
if (frameRate) {
this.tickRate = this.frameRate * this.subFrameRate;
} else {
this.tickRate = 1;
}
}
if (frameRateMultiplier) {
const multiplierResults = /^(\d+) (\d+)$/g.exec(frameRateMultiplier);
if (multiplierResults) {
const numerator = Number(multiplierResults[1]);
const denominator = Number(multiplierResults[2]);
const multiplierNum = numerator / denominator;
this.frameRate *= multiplierNum;
}
}
}
};
/**
* @const
* @private {!RegExp}
* @example 50.17% 10%
*/
shaka.text.TtmlTextParser.percentValues_ =
/^(\d{1,2}(?:\.\d+)?|100(?:\.0+)?)% (\d{1,2}(?:\.\d+)?|100(?:\.0+)?)%$/;
/**
* @const
* @private {!RegExp}
* @example 0.6% 90%
*/
shaka.text.TtmlTextParser.percentValue_ = /^(\d{1,2}(?:\.\d+)?|100)%$/;
/**
* @const
* @private {!RegExp}
* @example 100px, 8em, 0.80c
*/
shaka.text.TtmlTextParser.unitValues_ = /^(\d+px|\d+em|\d*\.?\d+c)$/;
/**
* @const
* @private {!RegExp}
* @example 100px
*/
shaka.text.TtmlTextParser.pixelValues_ = /^(\d+)px (\d+)px$/;
/**
* @const
* @private {!RegExp}
* @example 00:00:40:07 (7 frames) or 00:00:40:07.1 (7 frames, 1 subframe)
*/
shaka.text.TtmlTextParser.timeColonFormatFrames_ =
/^(\d{2,}):(\d{2}):(\d{2}):(\d{2})\.?(\d+)?$/;
/**
* @const
* @private {!RegExp}
* @example 00:00:40 or 00:40
*/
shaka.text.TtmlTextParser.timeColonFormat_ = /^(?:(\d{2,}):)?(\d{2}):(\d{2})$/;
/**
* @const
* @private {!RegExp}
* @example 01:02:43.0345555 or 02:43.03
*/
shaka.text.TtmlTextParser.timeColonFormatMilliseconds_ =
/^(?:(\d{2,}):)?(\d{2}):(\d{2}\.\d{2,})$/;
/**
* @const
* @private {!RegExp}
* @example 75f or 75.5f
*/
shaka.text.TtmlTextParser.timeFramesFormat_ = /^(\d*(?:\.\d*)?)f$/;
/**
* @const
* @private {!RegExp}
* @example 50t or 50.5t
*/
shaka.text.TtmlTextParser.timeTickFormat_ = /^(\d*(?:\.\d*)?)t$/;
/**
* @const
* @private {!RegExp}
* @example 3.45h, 3m or 4.20s
*/
shaka.text.TtmlTextParser.timeHMSFormat_ =
new RegExp(['^(?:(\\d*(?:\\.\\d*)?)h)?',
'(?:(\\d*(?:\\.\\d*)?)m)?',
'(?:(\\d*(?:\\.\\d*)?)s)?',
'(?:(\\d*(?:\\.\\d*)?)ms)?$'].join(''));
/**
* @const
* @private {!Object.<string, shaka.text.Cue.lineAlign>}
*/
shaka.text.TtmlTextParser.textAlignToLineAlign_ = {
'left': shaka.text.Cue.lineAlign.START,
'center': shaka.text.Cue.lineAlign.CENTER,
'right': shaka.text.Cue.lineAlign.END,
'start': shaka.text.Cue.lineAlign.START,
'end': shaka.text.Cue.lineAlign.END,
};
/**
* @const
* @private {!Object.<string, shaka.text.Cue.positionAlign>}
*/
shaka.text.TtmlTextParser.textAlignToPositionAlign_ = {
'left': shaka.text.Cue.positionAlign.LEFT,
'center': shaka.text.Cue.positionAlign.CENTER,
'right': shaka.text.Cue.positionAlign.RIGHT,
};
/**
* The namespace URL for TTML parameters. Can be assigned any name in the TTML
* document, not just "ttp:", so we use this with getAttributeNS() to ensure
* that we support arbitrary namespace names.
*
* @const {string}
* @private
*/
shaka.text.TtmlTextParser.parameterNs_ = 'http://www.w3.org/ns/ttml#parameter';
/**
* The namespace URL for TTML styles. Can be assigned any name in the TTML
* document, not just "tts:", so we use this with getAttributeNS() to ensure
* that we support arbitrary namespace names.
*
* @const {string}
* @private
*/
shaka.text.TtmlTextParser.styleNs_ = 'http://www.w3.org/ns/ttml#styling';
/**
* The namespace URL for EBU TTML styles. Can be assigned any name in the TTML
* document, not just "ebutts:", so we use this with getAttributeNS() to ensure
* that we support arbitrary namespace names.
*
* @const {string}
* @private
*/
shaka.text.TtmlTextParser.styleEbuttsNs_ = 'urn:ebu:tt:style';
/**
* The namespace URL for SMPTE fields.
* @const {string}
* @private
*/
shaka.text.TtmlTextParser.smpteNs_ =
'http://www.smpte-ra.org/schemas/2052-1/2010/smpte-tt';
shaka.text.TextEngine.registerParser(
'application/ttml+xml', () => new shaka.text.TtmlTextParser());