Source: lib/cea/ts_cea_parser.js

  1. /*! @license
  2.  * Shaka Player
  3.  * Copyright 2016 Google LLC
  4.  * SPDX-License-Identifier: Apache-2.0
  5.  */
  7. goog.provide('shaka.cea.TsCeaParser');
  9. goog.require('shaka.cea.CeaUtils');
  10. goog.require('shaka.cea.SeiProcessor');
  11. goog.require('shaka.media.ClosedCaptionParser');
  12. goog.require('shaka.util.BufferUtils');
  13. goog.require('shaka.util.TsParser');
  15. /**
  16.  * MPEG TS CEA parser.
  17.  * @implements {shaka.extern.ICeaParser}
  18.  * @export
  19.  */
  20. shaka.cea.TsCeaParser = class {
  21.   /** */
  22.   constructor() {
  23.     /**
  24.      * SEI data processor.
  25.      * @private
  26.      * @const {!shaka.cea.SeiProcessor}
  27.      */
  28.     this.seiProcessor_ = new shaka.cea.SeiProcessor();
  29.   }
  31.   /**
  32.    * @override
  33.    */
  34.   init(initSegment) {
  35.     // TS hasn't init segment
  36.   }
  38.   /**
  39.    * @override
  40.    */
  41.   parse(mediaSegment) {
  42.     const CeaUtils = shaka.cea.CeaUtils;
  44.     /** @type {!Array<!shaka.extern.ICeaParser.CaptionPacket>} **/
  45.     const captionPackets = [];
  47.     const uint8ArrayData = shaka.util.BufferUtils.toUint8(mediaSegment);
  48.     if (!shaka.util.TsParser.probe(uint8ArrayData)) {
  49.       return captionPackets;
  50.     }
  51.     const tsParser = new shaka.util.TsParser().parse(uint8ArrayData);
  52.     const codecs = tsParser.getCodecs();
  53.     const videoNalus = tsParser.getVideoNalus();
  54.     const validNaluTypes = [];
  55.     switch (codecs.video) {
  56.       case 'avc':
  57.         validNaluTypes.push(CeaUtils.H264_NALU_TYPE_SEI);
  58.         break;
  59.       case 'hvc':
  60.         validNaluTypes.push(CeaUtils.H265_PREFIX_NALU_TYPE_SEI);
  61.         validNaluTypes.push(CeaUtils.H265_SUFFIX_NALU_TYPE_SEI);
  62.         break;
  63.     }
  64.     if (!validNaluTypes.length) {
  65.       return captionPackets;
  66.     }
  67.     for (const nalu of videoNalus) {
  68.       if (validNaluTypes.includes(nalu.type) && nalu.time != null) {
  69.         for (const packet of this.seiProcessor_.process(nalu.data)) {
  70.           captionPackets.push({
  71.             packet: packet,
  72.             pts: nalu.time,
  73.           });
  74.         }
  75.       }
  76.     }
  77.     return captionPackets;
  78.   }
  79. };
  81. shaka.media.ClosedCaptionParser.registerParser('video/mp2t',
  82.     () => new shaka.cea.TsCeaParser());