mtags/parsers/id3v1.js

Media file tag parser

/*
 * JavaScript ID3 Tag Reader 0.1.2
 * Copyright (c) 2008 Jacob Seidelin, cupboy@gmail.com, http://blog.nihilogic.dk/
 * MIT License [http://www.opensource.org/licenses/mit-license.php]
 * 
 * Extended by António Afonso (antonio.afonso@opera.com), Opera Software ASA
 * Modified by António Afonso (antonio.afonso gmail.com)
 */

var genres = [
  "Blues","Classic Rock","Country","Dance","Disco","Funk","Grunge",
  "Hip-Hop","Jazz","Metal","New Age","Oldies","Other","Pop","R&B",
  "Rap","Reggae","Rock","Techno","Industrial","Alternative","Ska",
  "Death Metal","Pranks","Soundtrack","Euro-Techno","Ambient",
  "Trip-Hop","Vocal","Jazz+Funk","Fusion","Trance","Classical",
  "Instrumental","Acid","House","Game","Sound Clip","Gospel",
  "Noise","AlternRock","Bass","Soul","Punk","Space","Meditative",
  "Instrumental Pop","Instrumental Rock","Ethnic","Gothic",
  "Darkwave","Techno-Industrial","Electronic","Pop-Folk",
  "Eurodance","Dream","Southern Rock","Comedy","Cult","Gangsta",
  "Top 40","Christian Rap","Pop/Funk","Jungle","Native American",
  "Cabaret","New Wave","Psychadelic","Rave","Showtunes","Trailer",
  "Lo-Fi","Tribal","Acid Punk","Acid Jazz","Polka","Retro",
  "Musical","Rock & Roll","Hard Rock","Folk","Folk-Rock",
  "National Folk","Swing","Fast Fusion","Bebob","Latin","Revival",
  "Celtic","Bluegrass","Avantgarde","Gothic Rock","Progressive Rock",
  "Psychedelic Rock","Symphonic Rock","Slow Rock","Big Band",
  "Chorus","Easy Listening","Acoustic","Humour","Speech","Chanson",
  "Opera","Chamber Music","Sonata","Symphony","Booty Bass","Primus",
  "Porn Groove","Satire","Slow Jam","Club","Tango","Samba",
  "Folklore","Ballad","Power Ballad","Rhythmic Soul","Freestyle",
  "Duet","Punk Rock","Drum Solo","Acapella","Euro-House","Dance Hall"
];

exports.loadData = function (data, callback) {
    var length = data.getLength();
    data.loadRange([length-128-1, length], callback);
};

exports.readTagsFromData = function (data) {
  var offset = data.getLength() - 128;
  var header = data.getStringAt(offset, 3);
  if (header == "TAG") {
    var title = data.getStringAt(offset + 3, 30).replace(/\0/g, "");
    var artist = data.getStringAt(offset + 33, 30).replace(/\0/g, "");
    var album = data.getStringAt(offset + 63, 30).replace(/\0/g, "");
    var year = data.getStringAt(offset + 93, 4).replace(/\0/g, "");

    var trackFlag = data.getByteAt(offset + 97 + 28);
    if (trackFlag == 0) {
      var comment = data.getStringAt(offset + 97, 28).replace(/\0/g, "");
      var track = data.getByteAt(offset + 97 + 29);
    } else {
      var comment = "";
      var track = 0;
    }

    var genreIdx = data.getByteAt(offset + 97 + 30);
    if (genreIdx < 255) {
      var genre = genres[genreIdx];
    } else {
      var genre = "";
    }

    return {
        "version" : '1.1',
      "title" : title,
      "artist" : artist,
      "album" : album,
      "year" : year,
      "comment" : comment,
      "track" : track,
      "genre" : genre
    }
  } else {
    return {};
  }
};