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();
  30.     /** @private {?shaka.util.TsParser} */
  31.     this.tsParser_ = null;
  32.   }
  34.   /**
  35.    * @override
  36.    */
  37.   init(initSegment) {
  38.     // TS hasn't init segment
  39.   }
  41.   /**
  42.    * @override
  43.    */
  44.   parse(mediaSegment) {
  45.     const CeaUtils = shaka.cea.CeaUtils;
  47.     if (!this.tsParser_) {
  48.       this.tsParser_ = new shaka.util.TsParser();
  49.     } else {
  50.       this.tsParser_.clearData();
  51.     }
  53.     /** @type {!Array<!shaka.extern.ICeaParser.CaptionPacket>} **/
  54.     const captionPackets = [];
  56.     const uint8ArrayData = shaka.util.BufferUtils.toUint8(mediaSegment);
  57.     if (!shaka.util.TsParser.probe(uint8ArrayData)) {
  58.       return captionPackets;
  59.     }
  60.     const tsParser = this.tsParser_.parse(uint8ArrayData);
  61.     const codecs = tsParser.getCodecs();
  62.     const videoNalus = tsParser.getVideoNalus();
  63.     const validNaluTypes = [];
  64.     switch (codecs.video) {
  65.       case 'avc':
  66.         validNaluTypes.push(CeaUtils.H264_NALU_TYPE_SEI);
  67.         break;
  68.       case 'hvc':
  69.         validNaluTypes.push(CeaUtils.H265_PREFIX_NALU_TYPE_SEI);
  70.         validNaluTypes.push(CeaUtils.H265_SUFFIX_NALU_TYPE_SEI);
  71.         break;
  72.     }
  73.     if (!validNaluTypes.length) {
  74.       return captionPackets;
  75.     }
  76.     for (const nalu of videoNalus) {
  77.       if (validNaluTypes.includes(nalu.type) && nalu.time != null) {
  78.         for (const packet of this.seiProcessor_.process(nalu.data)) {
  79.           captionPackets.push({
  80.             packet: packet,
  81.             pts: nalu.time,
  82.           });
  83.         }
  84.       }
  85.     }
  86.     return captionPackets;
  87.   }
  88. };
  90. shaka.media.ClosedCaptionParser.registerParser('video/mp2t',
  91.     () => new shaka.cea.TsCeaParser());