Source: lib/transmuxer/opus.js

  1. /*! @license
  2.  * Shaka Player
  3.  * Copyright 2016 Google LLC
  4.  * SPDX-License-Identifier: Apache-2.0
  5.  */
  7. goog.provide('shaka.transmuxer.Opus');
  9. goog.requireType('shaka.util.TsParser');
  12. /**
  13.  * Opus utils
  14.  */
  15. shaka.transmuxer.Opus = class {
  16.   /**
  17.    * @param {!shaka.util.TsParser.OpusMetadata} metadata
  18.    * @return {!Uint8Array}
  19.    */
  20.   static getAudioConfig(metadata) {
  21.     let mapping = [];
  22.     switch (metadata.channelConfigCode) {
  23.       case 0x01:
  24.       case 0x02:
  25.         mapping = [0x0];
  26.         break;
  27.       case 0x00: // dualmono
  28.         mapping = [0xFF, 1, 1, 0, 1];
  29.         break;
  30.       case 0x80: // dualmono
  31.         mapping = [0xFF, 2, 0, 0, 1];
  32.         break;
  33.       case 0x03:
  34.         mapping = [0x01, 2, 1, 0, 2, 1];
  35.         break;
  36.       case 0x04:
  37.         mapping = [0x01, 2, 2, 0, 1, 2, 3];
  38.         break;
  39.       case 0x05:
  40.         mapping = [0x01, 3, 2, 0, 4, 1, 2, 3];
  41.         break;
  42.       case 0x06:
  43.         mapping = [0x01, 4, 2, 0, 4, 1, 2, 3, 5];
  44.         break;
  45.       case 0x07:
  46.         mapping = [0x01, 4, 2, 0, 4, 1, 2, 3, 5, 6];
  47.         break;
  48.       case 0x08:
  49.         mapping = [0x01, 5, 3, 0, 6, 1, 2, 3, 4, 5, 7];
  50.         break;
  51.       case 0x82:
  52.         mapping = [0x01, 1, 2, 0, 1];
  53.         break;
  54.       case 0x83:
  55.         mapping = [0x01, 1, 3, 0, 1, 2];
  56.         break;
  57.       case 0x84:
  58.         mapping = [0x01, 1, 4, 0, 1, 2, 3];
  59.         break;
  60.       case 0x85:
  61.         mapping = [0x01, 1, 5, 0, 1, 2, 3, 4];
  62.         break;
  63.       case 0x86:
  64.         mapping = [0x01, 1, 6, 0, 1, 2, 3, 4, 5];
  65.         break;
  66.       case 0x87:
  67.         mapping = [0x01, 1, 7, 0, 1, 2, 3, 4, 5, 6];
  68.         break;
  69.       case 0x88:
  70.         mapping = [0x01, 1, 8, 0, 1, 2, 3, 4, 5, 6, 7];
  71.         break;
  72.     }
  74.     return new Uint8Array([
  75.       0x00,         // Version (1)
  76.       metadata.channelCount, // OutputChannelCount: 2
  77.       0x00, 0x00,   // PreSkip: 2
  78.       (metadata.sampleRate >>> 24) & 0xFF,  // Audio sample rate: 4
  79.       (metadata.sampleRate >>> 17) & 0xFF,
  80.       (metadata.sampleRate >>> 8) & 0xFF,
  81.       (metadata.sampleRate >>> 0) & 0xFF,
  82.       0x00, 0x00,  // Global Gain : 2
  83.       ...mapping,
  84.     ]);
  85.   }
  86. };
  88. /**
  89.  * @const {number}
  90.  */
  91. shaka.transmuxer.Opus.OPUS_AUDIO_SAMPLE_PER_FRAME = 960;