shaka-player/lib/text/sbv_text_parser.js

DASH/EME video player library

/*! @license
 * Shaka Player
 * Copyright 2016 Google LLC
 * SPDX-License-Identifier: Apache-2.0
 */

goog.provide('shaka.text.SbvTextParser');

goog.require('goog.asserts');
goog.require('shaka.text.Cue');
goog.require('shaka.text.TextEngine');
goog.require('shaka.util.Error');
goog.require('shaka.util.StringUtils');
goog.require('shaka.util.TextParser');


/**
 * @implements {shaka.extern.TextParser}
 * @export
 */
shaka.text.SbvTextParser = class {
  /**
   * @override
   * @export
   */
  parseInit(data) {
    goog.asserts.assert(false, 'SubViewer does not have init segments');
  }

  /**
   * @override
   * @export
   */
  setSequenceMode(sequenceMode) {
    // Unused.
  }

  /**
   * @override
   * @export
   */
  setManifestType(manifestType) {
    // Unused.
  }

  /**
   * @override
   * @export
   */
  parseMedia(data, time) {
    const SbvTextParser = shaka.text.SbvTextParser;
    const StringUtils = shaka.util.StringUtils;

    // Get the input as a string.
    const strFromData = StringUtils.fromUTF8(data);
    // remove dos newlines
    let str = strFromData.replace(/\r+/g, '');
    // trim white space start and end
    str = str.trim();

    /** @type {!Array.<!shaka.text.Cue>} */
    const cues = [];

    // Supports no cues
    if (str == '') {
      return cues;
    }

    // get cues
    const blocklist = str.split('\n\n');
    for (const block of blocklist) {
      const lines = block.split('\n');
      // Parse the times.
      const parser = new shaka.util.TextParser(lines[0]);
      const start = SbvTextParser.parseTime_(parser);
      const expect = parser.readRegex(/,/g);
      const end = SbvTextParser.parseTime_(parser);

      if (start == null || expect == 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,
            'Could not parse cue time range in SubViewer');
      }

      // Get the payload.
      const payload = lines.slice(1).join('\n').trim();

      const cue = new shaka.text.Cue(start, end, payload);
      cues.push(cue);
    }

    return cues;
  }

  /**
   * Parses a SubViewer time from the given parser.
   *
   * @param {!shaka.util.TextParser} parser
   * @return {?number}
   * @private
   */
  static parseTime_(parser) {
    // 00:00.000 or 00:00:00.000 or 0:00:00.000 or
    // 00:00.00 or 00:00:00.00 or 0:00:00.00
    const regexExpresion = /(?:(\d{1,}):)?(\d{2}):(\d{2})\.(\d{2,3})/g;
    const results = parser.readRegex(regexExpresion);
    if (results == null) {
      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]);
    const seconds = Number(results[3]);
    const milliseconds = Number(results[4]);
    if (minutes > 59 || seconds > 59) {
      return null;
    }

    return (milliseconds / 1000) + seconds + (minutes * 60) + (hours * 3600);
  }
};


shaka.text.TextEngine.registerParser(
    'text/x-subviewer', () => new shaka.text.SbvTextParser());