jtBaseApp/node_modules/mux.js/cjs/tools/flv-inspector.js

/**
 * mux.js
 *
 * Copyright (c) Brightcove
 * Licensed Apache-2.0 https://github.com/videojs/mux.js/blob/master/LICENSE
 */
'use strict';

var tagTypes = {
  0x08: 'audio',
  0x09: 'video',
  0x12: 'metadata'
},
    hex = function hex(val) {
  return '0x' + ('00' + val.toString(16)).slice(-2).toUpperCase();
},
    hexStringList = function hexStringList(data) {
  var arr = [],
      i;

  while (data.byteLength > 0) {
    i = 0;
    arr.push(hex(data[i++]));
    data = data.subarray(i);
  }

  return arr.join(' ');
},
    parseAVCTag = function parseAVCTag(tag, obj) {
  var avcPacketTypes = ['AVC Sequence Header', 'AVC NALU', 'AVC End-of-Sequence'],
      compositionTime = tag[1] & parseInt('01111111', 2) << 16 | tag[2] << 8 | tag[3];
  obj = obj || {};
  obj.avcPacketType = avcPacketTypes[tag[0]];
  obj.CompositionTime = tag[1] & parseInt('10000000', 2) ? -compositionTime : compositionTime;

  if (tag[0] === 1) {
    obj.nalUnitTypeRaw = hexStringList(tag.subarray(4, 100));
  } else {
    obj.data = hexStringList(tag.subarray(4));
  }

  return obj;
},
    parseVideoTag = function parseVideoTag(tag, obj) {
  var frameTypes = ['Unknown', 'Keyframe (for AVC, a seekable frame)', 'Inter frame (for AVC, a nonseekable frame)', 'Disposable inter frame (H.263 only)', 'Generated keyframe (reserved for server use only)', 'Video info/command frame'],
      codecID = tag[0] & parseInt('00001111', 2);
  obj = obj || {};
  obj.frameType = frameTypes[(tag[0] & parseInt('11110000', 2)) >>> 4];
  obj.codecID = codecID;

  if (codecID === 7) {
    return parseAVCTag(tag.subarray(1), obj);
  }

  return obj;
},
    parseAACTag = function parseAACTag(tag, obj) {
  var packetTypes = ['AAC Sequence Header', 'AAC Raw'];
  obj = obj || {};
  obj.aacPacketType = packetTypes[tag[0]];
  obj.data = hexStringList(tag.subarray(1));
  return obj;
},
    parseAudioTag = function parseAudioTag(tag, obj) {
  var formatTable = ['Linear PCM, platform endian', 'ADPCM', 'MP3', 'Linear PCM, little endian', 'Nellymoser 16-kHz mono', 'Nellymoser 8-kHz mono', 'Nellymoser', 'G.711 A-law logarithmic PCM', 'G.711 mu-law logarithmic PCM', 'reserved', 'AAC', 'Speex', 'MP3 8-Khz', 'Device-specific sound'],
      samplingRateTable = ['5.5-kHz', '11-kHz', '22-kHz', '44-kHz'],
      soundFormat = (tag[0] & parseInt('11110000', 2)) >>> 4;
  obj = obj || {};
  obj.soundFormat = formatTable[soundFormat];
  obj.soundRate = samplingRateTable[(tag[0] & parseInt('00001100', 2)) >>> 2];
  obj.soundSize = (tag[0] & parseInt('00000010', 2)) >>> 1 ? '16-bit' : '8-bit';
  obj.soundType = tag[0] & parseInt('00000001', 2) ? 'Stereo' : 'Mono';

  if (soundFormat === 10) {
    return parseAACTag(tag.subarray(1), obj);
  }

  return obj;
},
    parseGenericTag = function parseGenericTag(tag) {
  return {
    tagType: tagTypes[tag[0]],
    dataSize: tag[1] << 16 | tag[2] << 8 | tag[3],
    timestamp: tag[7] << 24 | tag[4] << 16 | tag[5] << 8 | tag[6],
    streamID: tag[8] << 16 | tag[9] << 8 | tag[10]
  };
},
    inspectFlvTag = function inspectFlvTag(tag) {
  var header = parseGenericTag(tag);

  switch (tag[0]) {
    case 0x08:
      parseAudioTag(tag.subarray(11), header);
      break;

    case 0x09:
      parseVideoTag(tag.subarray(11), header);
      break;

    case 0x12:
  }

  return header;
},
    inspectFlv = function inspectFlv(bytes) {
  var i = 9,
      // header
  dataSize,
      parsedResults = [],
      tag; // traverse the tags

  i += 4; // skip previous tag size

  while (i < bytes.byteLength) {
    dataSize = bytes[i + 1] << 16;
    dataSize |= bytes[i + 2] << 8;
    dataSize |= bytes[i + 3];
    dataSize += 11;
    tag = bytes.subarray(i, i + dataSize);
    parsedResults.push(inspectFlvTag(tag));
    i += dataSize + 4;
  }

  return parsedResults;
},
    textifyFlv = function textifyFlv(flvTagArray) {
  return JSON.stringify(flvTagArray, null, 2);
};

module.exports = {
  inspectTag: inspectFlvTag,
  inspect: inspectFlv,
  textify: textifyFlv
};