containers.js 5.4 KB
import { toUint8, bytesMatch } from './byte-helpers.js';
import { findBox } from './mp4-helpers.js';
import { findEbml, EBML_TAGS } from './ebml-helpers.js';
import { getId3Offset } from './id3-helpers.js';
import { findH264Nal, findH265Nal } from './nal-helpers.js';
var CONSTANTS = {
  // "webm" string literal in hex
  'webm': toUint8([0x77, 0x65, 0x62, 0x6d]),
  // "matroska" string literal in hex
  'matroska': toUint8([0x6d, 0x61, 0x74, 0x72, 0x6f, 0x73, 0x6b, 0x61]),
  // "fLaC" string literal in hex
  'flac': toUint8([0x66, 0x4c, 0x61, 0x43]),
  // "OggS" string literal in hex
  'ogg': toUint8([0x4f, 0x67, 0x67, 0x53]),
  // ac-3 sync byte, also works for ec-3 as that is simply a codec
  // of ac-3
  'ac3': toUint8([0x0b, 0x77]),
  // "RIFF" string literal in hex used for wav and avi
  'riff': toUint8([0x52, 0x49, 0x46, 0x46]),
  // "AVI" string literal in hex
  'avi': toUint8([0x41, 0x56, 0x49]),
  // "WAVE" string literal in hex
  'wav': toUint8([0x57, 0x41, 0x56, 0x45]),
  // "ftyp3g" string literal in hex
  '3gp': toUint8([0x66, 0x74, 0x79, 0x70, 0x33, 0x67]),
  // "ftyp" string literal in hex
  'mp4': toUint8([0x66, 0x74, 0x79, 0x70]),
  // "styp" string literal in hex
  'fmp4': toUint8([0x73, 0x74, 0x79, 0x70]),
  // "ftypqt" string literal in hex
  'mov': toUint8([0x66, 0x74, 0x79, 0x70, 0x71, 0x74]),
  // moov string literal in hex
  'moov': toUint8([0x6D, 0x6F, 0x6F, 0x76]),
  // moof string literal in hex
  'moof': toUint8([0x6D, 0x6F, 0x6F, 0x66])
};
var _isLikely = {
  aac: function aac(bytes) {
    var offset = getId3Offset(bytes);
    return bytesMatch(bytes, [0xFF, 0x10], {
      offset: offset,
      mask: [0xFF, 0x16]
    });
  },
  mp3: function mp3(bytes) {
    var offset = getId3Offset(bytes);
    return bytesMatch(bytes, [0xFF, 0x02], {
      offset: offset,
      mask: [0xFF, 0x06]
    });
  },
  webm: function webm(bytes) {
    var docType = findEbml(bytes, [EBML_TAGS.EBML, EBML_TAGS.DocType])[0]; // check if DocType EBML tag is webm

    return bytesMatch(docType, CONSTANTS.webm);
  },
  mkv: function mkv(bytes) {
    var docType = findEbml(bytes, [EBML_TAGS.EBML, EBML_TAGS.DocType])[0]; // check if DocType EBML tag is matroska

    return bytesMatch(docType, CONSTANTS.matroska);
  },
  mp4: function mp4(bytes) {
    // if this file is another base media file format, it is not mp4
    if (_isLikely['3gp'](bytes) || _isLikely.mov(bytes)) {
      return false;
    } // if this file starts with a ftyp or styp box its mp4


    if (bytesMatch(bytes, CONSTANTS.mp4, {
      offset: 4
    }) || bytesMatch(bytes, CONSTANTS.fmp4, {
      offset: 4
    })) {
      return true;
    } // if this file starts with a moof/moov box its mp4


    if (bytesMatch(bytes, CONSTANTS.moof, {
      offset: 4
    }) || bytesMatch(bytes, CONSTANTS.moov, {
      offset: 4
    })) {
      return true;
    }
  },
  mov: function mov(bytes) {
    return bytesMatch(bytes, CONSTANTS.mov, {
      offset: 4
    });
  },
  '3gp': function gp(bytes) {
    return bytesMatch(bytes, CONSTANTS['3gp'], {
      offset: 4
    });
  },
  ac3: function ac3(bytes) {
    var offset = getId3Offset(bytes);
    return bytesMatch(bytes, CONSTANTS.ac3, {
      offset: offset
    });
  },
  ts: function ts(bytes) {
    if (bytes.length < 189 && bytes.length >= 1) {
      return bytes[0] === 0x47;
    }

    var i = 0; // check the first 376 bytes for two matching sync bytes

    while (i + 188 < bytes.length && i < 188) {
      if (bytes[i] === 0x47 && bytes[i + 188] === 0x47) {
        return true;
      }

      i += 1;
    }

    return false;
  },
  flac: function flac(bytes) {
    var offset = getId3Offset(bytes);
    return bytesMatch(bytes, CONSTANTS.flac, {
      offset: offset
    });
  },
  ogg: function ogg(bytes) {
    return bytesMatch(bytes, CONSTANTS.ogg);
  },
  avi: function avi(bytes) {
    return bytesMatch(bytes, CONSTANTS.riff) && bytesMatch(bytes, CONSTANTS.avi, {
      offset: 8
    });
  },
  wav: function wav(bytes) {
    return bytesMatch(bytes, CONSTANTS.riff) && bytesMatch(bytes, CONSTANTS.wav, {
      offset: 8
    });
  },
  'h264': function h264(bytes) {
    // find seq_parameter_set_rbsp
    return findH264Nal(bytes, 7, 3).length;
  },
  'h265': function h265(bytes) {
    // find video_parameter_set_rbsp or seq_parameter_set_rbsp
    return findH265Nal(bytes, [32, 33], 3).length;
  }
}; // get all the isLikely functions
// but make sure 'ts' is above h264 and h265
// but below everything else as it is the least specific

var isLikelyTypes = Object.keys(_isLikely) // remove ts, h264, h265
.filter(function (t) {
  return t !== 'ts' && t !== 'h264' && t !== 'h265';
}) // add it back to the bottom
.concat(['ts', 'h264', 'h265']); // make sure we are dealing with uint8 data.

isLikelyTypes.forEach(function (type) {
  var isLikelyFn = _isLikely[type];

  _isLikely[type] = function (bytes) {
    return isLikelyFn(toUint8(bytes));
  };
}); // export after wrapping

export var isLikely = _isLikely; // A useful list of file signatures can be found here
// https://en.wikipedia.org/wiki/List_of_file_signatures

export var detectContainerForBytes = function detectContainerForBytes(bytes) {
  bytes = toUint8(bytes);

  for (var i = 0; i < isLikelyTypes.length; i++) {
    var type = isLikelyTypes[i];

    if (isLikely[type](bytes)) {
      return type;
    }
  }

  return '';
}; // fmp4 is not a container

export var isLikelyFmp4MediaSegment = function isLikelyFmp4MediaSegment(bytes) {
  return findBox(bytes, ['moof']).length > 0;
};