CEA-708 Decoder (#2648)

build/types/cea

@@ -1,8 +1,12 @@
 # Inband closed caption support.
 
 +../../lib/cea/cea_decoder.js
++../../lib/cea/cea_utils.js
 +../../lib/cea/cea608_data_channel.js
 +../../lib/cea/cea608_memory.js
++../../lib/cea/cea708_service.js
++../../lib/cea/cea708_window.js
++../../lib/cea/dtvcc_packet_builder.js
 +../../lib/cea/i_caption_decoder.js
 +../../lib/cea/i_cea_parser.js
 +../../lib/cea/mp4_cea_parser.js

lib/cea/cea608_data_channel.js

@@ -7,6 +7,7 @@
 goog.provide('shaka.cea.Cea608DataChannel');
 
 goog.require('shaka.cea.Cea608Memory');
+goog.require('shaka.cea.CeaUtils');
 
 
 /**
@@ -114,7 +115,7 @@ shaka.cea.Cea608DataChannel = class {
     const attr = (b2 & 0x1E) >> 1;
 
     // Set up the defaults.
-    let textColor = shaka.cea.Cea608Memory.DEFAULT_TXT_COLOR;
+    let textColor = shaka.cea.CeaUtils.DEFAULT_TXT_COLOR;
     let italics = false;
 
 
@@ -157,7 +158,7 @@ shaka.cea.Cea608DataChannel = class {
     this.curbuf_.setTextColor(textColor);
 
     // Clear the background color, since new row (PAC) should reset ALL styles.
-    this.curbuf_.setBackgroundColor(shaka.cea.Cea608Memory.DEFAULT_BG_COLOR);
+    this.curbuf_.setBackgroundColor(shaka.cea.CeaUtils.DEFAULT_BG_COLOR);
   }
 
   /**
@@ -169,13 +170,13 @@ shaka.cea.Cea608DataChannel = class {
     // Clear all pre-existing midrow style attributes.
     this.curbuf_.setUnderline(false);
     this.curbuf_.setItalics(false);
-    this.curbuf_.setTextColor(shaka.cea.Cea608Memory.DEFAULT_TXT_COLOR);
+    this.curbuf_.setTextColor(shaka.cea.CeaUtils.DEFAULT_TXT_COLOR);
 
     // Mid-row attrs use a space.
     this.curbuf_.addChar(
         shaka.cea.Cea608Memory.CharSet.BASIC_NORTH_AMERICAN, ' '.charCodeAt(0));
 
-    let textColor = shaka.cea.Cea608Memory.DEFAULT_TXT_COLOR;
+    let textColor = shaka.cea.CeaUtils.DEFAULT_TXT_COLOR;
     let italics = false;
 
     // Midrow codes set underline on last (LSB) bit.
@@ -200,7 +201,7 @@ shaka.cea.Cea608DataChannel = class {
    * @private
    */
   controlBackgroundAttribute_(b1, b2) {
-    let backgroundColor = shaka.cea.Cea608Memory.DEFAULT_BG_COLOR;
+    let backgroundColor = shaka.cea.CeaUtils.DEFAULT_BG_COLOR;
     if ((b1 & 0x07) === 0x0) {
       // If background provided, last 3 bits of b1 are |0|0|0|. Color is in b2.
       backgroundColor = shaka.cea.Cea608DataChannel.BG_COLORS[(b2 & 0xe) >> 1];

lib/cea/cea608_memory.js

@@ -5,8 +5,8 @@
  */
 
 goog.provide('shaka.cea.Cea608Memory');
-goog.provide('shaka.cea.Cea608Char');
 
+goog.require('shaka.cea.CeaUtils');
 goog.require('shaka.text.Cue');
 
 
@@ -21,7 +21,7 @@ shaka.cea.Cea608Memory = class {
   constructor(fieldNum, channelNum) {
     /**
      * Buffer for storing decoded characters.
-     * @private @const {!Array<!Array<!shaka.cea.Cea608Char>>}
+     * @private @const {!Array<!Array<!shaka.cea.CeaUtils.StyledChar>>}
      */
     this.rows_ = [];
 
@@ -62,12 +62,12 @@ shaka.cea.Cea608Memory = class {
     /**
      * @private {!string}
      */
-    this.textColor_ = shaka.cea.Cea608Memory.DEFAULT_TXT_COLOR;
+    this.textColor_ = shaka.cea.CeaUtils.DEFAULT_TXT_COLOR;
 
     /**
      * @private {!string}
      */
-    this.backgroundColor_ = shaka.cea.Cea608Memory.DEFAULT_BG_COLOR;
+    this.backgroundColor_ = shaka.cea.CeaUtils.DEFAULT_BG_COLOR;
 
     this.reset();
   }
@@ -80,121 +80,10 @@ shaka.cea.Cea608Memory = class {
    */
   forceEmit(startTime, endTime) {
     const stream = `CC${(this.fieldNum_<< 1) | this.channelNum_ +1}`;
-
-    // Find the first and last row that contains characters.
-    let firstNonEmptyRow = -1;
-    let lastNonEmptyRow = -1;
-
-    for (let i = 0; i < this.rows_.length; i++) {
-      if (this.rows_[i].length) {
-        firstNonEmptyRow = i;
-        break;
-      }
-    }
-
-    for (let i = this.rows_.length - 1; i >= 0; i--) {
-      if (this.rows_[i].length) {
-        lastNonEmptyRow = i;
-        break;
-      }
-    }
-
-    // Exit early if no non-empty row was found.
-    if (firstNonEmptyRow === -1 || lastNonEmptyRow === -1) {
-      return null;
-    }
-
-    // Keeps track of the current styles for a cue being emitted.
-    let currentUnderline = false;
-    let currentItalics = false;
-    let currentTextColor = shaka.cea.Cea608Memory.DEFAULT_TXT_COLOR;
-    let currentBackgroundColor = shaka.cea.Cea608Memory.DEFAULT_BG_COLOR;
-
-    // Create first cue that will be nested in top level cue. Default styles.
-    let currentCue = this.createStyledCue_(startTime, endTime,
-        currentUnderline, currentItalics,
-        currentTextColor, currentBackgroundColor);
-
-    // Logic: Reduce rows into a single top level cue containing nested cues.
-    // Each nested cue corresponds either a style change or a line break.
     const topLevelCue = new shaka.text.Cue(
         startTime, endTime, /* payload= */ '');
-
-    for (let i = firstNonEmptyRow; i <= lastNonEmptyRow; i++) {
-      for (const styledChar of this.rows_[i]) {
-        const underline = styledChar.isUnderlined();
-        const italics = styledChar.isItalicized();
-        const textColor = styledChar.getTextColor();
-        const backgroundColor = styledChar.getBackgroundColor();
-
-        // If any style properties have changed, we need to open a new cue.
-        if (underline != currentUnderline || italics != currentItalics ||
-            textColor != currentTextColor ||
-            backgroundColor != currentBackgroundColor) {
-          // Push the currently built cue and start a new cue, with new styles.
-          if (currentCue.payload) {
-            topLevelCue.nestedCues.push(currentCue);
-          }
-          currentCue = this.createStyledCue_(startTime, endTime,
-              underline, italics, textColor, backgroundColor);
-
-          currentUnderline = underline;
-          currentItalics = italics;
-          currentTextColor = textColor;
-          currentBackgroundColor = backgroundColor;
-        }
-
-        currentCue.payload += styledChar.getChar();
-      }
-      if (currentCue.payload) {
-        topLevelCue.nestedCues.push(currentCue);
-      }
-
-      // Create and push a linebreak cue to create a new line.
-      if (i !== lastNonEmptyRow) {
-        const spacerCue = new shaka.text.Cue(
-            startTime, endTime, /* payload= */ '');
-        spacerCue.spacer = true;
-        topLevelCue.nestedCues.push(spacerCue);
-      }
-
-      // Create a new cue.
-      currentCue = this.createStyledCue_(startTime, endTime,
-          currentUnderline, currentItalics,
-          currentTextColor, currentBackgroundColor);
-    }
-
-    if (topLevelCue.nestedCues.length) {
-      return {
-        cue: topLevelCue,
-        stream,
-      };
-    }
-
-    return null;
-  }
-
-  /**
-   * @param {!number} startTime
-   * @param {!number} endTime
-   * @param {!boolean} underline
-   * @param {!boolean} italics
-   * @param {!string} txtColor
-   * @param {!string} bgColor
-   * @return {!shaka.text.Cue}
-   * @private
-   */
-  createStyledCue_(startTime, endTime, underline, italics, txtColor, bgColor) {
-    const cue = new shaka.text.Cue(startTime, endTime, /* payload= */ '');
-    if (underline) {
-      cue.textDecoration.push(shaka.text.Cue.textDecoration.UNDERLINE);
-    }
-    if (italics) {
-      cue.fontStyle = shaka.text.Cue.fontStyle.ITALIC;
-    }
-    cue.color = txtColor;
-    cue.backgroundColor = bgColor;
-    return cue;
+    return shaka.cea.CeaUtils.getParsedCaption(
+        topLevelCue, stream, this.rows_, startTime, endTime);
   }
 
   /**
@@ -273,8 +162,9 @@ shaka.cea.Cea608Memory = class {
     }
 
     if (char) {
-      const styledChar = new shaka.cea.Cea608Char(char, this.underline_,
-          this.italics_, this.backgroundColor_, this.textColor_);
+      const styledChar = new shaka.cea.CeaUtils.StyledChar(
+          char, this.underline_, this.italics_,
+          this.backgroundColor_, this.textColor_);
       this.rows_[this.row_].push(styledChar);
     }
   }
@@ -360,88 +250,12 @@ shaka.cea.Cea608Memory = class {
   }
 };
 
-shaka.cea.Cea608Char = class {
-  constructor(character, underline, italics, backgroundColor, textColor) {
-    /**
-     * @private {!string}
-     */
-    this.character_ = character;
-
-    /**
-     * @private {!boolean}
-     */
-    this.underline_ = underline;
-
-    /**
-     * @private {!boolean}
-     */
-    this.italics_ = italics;
-
-    /**
-     * @private {!string}
-     */
-    this.backgroundColor_ = backgroundColor;
-
-    /**
-     * @private {!string}
-     */
-    this.textColor_ = textColor;
-  }
-
-  /**
-   * @return {!string}
-   */
-  getChar() {
-    return this.character_;
-  }
-
-  /**
-   * @return {!boolean}
-   */
-  isUnderlined() {
-    return this.underline_;
-  }
-
-  /**
-   * @return {!boolean}
-   */
-  isItalicized() {
-    return this.italics_;
-  }
-
-  /**
-   * @return {!string}
-   */
-  getBackgroundColor() {
-    return this.backgroundColor_;
-  }
-
-  /**
-   * @return {!string}
-   */
-  getTextColor() {
-    return this.textColor_;
-  }
-};
-
 /**
  * Maximum number of rows in the buffer.
  * @const {!number}
  */
 shaka.cea.Cea608Memory.CC_ROWS = 15;
 
-/**
- * Default background color for text.
- * @const {!string}
- */
-shaka.cea.Cea608Memory.DEFAULT_BG_COLOR = 'black';
-
-/**
- * Default text color.
- * @const {!string}
- */
-shaka.cea.Cea608Memory.DEFAULT_TXT_COLOR = 'white';
-
 /**
  * Characters sets.
  * @const @enum {!number}