Scream Tracker 3 module: JavaScript parsing library

Scream Tracker 3 module is a tracker music file format that, as all tracker music, bundles both sound samples and instructions on which notes to play. It originates from a Scream Tracker 3 music editor (1994) by Future Crew, derived from original Scream Tracker 2 (.stm) module format.

Instrument descriptions in S3M format allow to use either digital samples or setup and control AdLib (OPL2) synth.

Music is organized in so called patterns. "Pattern" is a generally a 64-row long table, which instructs which notes to play on which time measure. "Patterns" are played one-by-one in a sequence determined by orders, which is essentially an array of pattern IDs

  • this way it's possible to reuse certain patterns more than once for repetitive musical phrases.

File extension

s3m

KS implementation details

License: CC0-1.0

References

This page hosts a formal specification of Scream Tracker 3 module using Kaitai Struct. This specification can be automatically translated into a variety of programming languages to get a parsing library.

Usage

Runtime library

All parsing code for JavaScript generated by Kaitai Struct depends on the JavaScript runtime library. You have to install it before you can parse data.

The JavaScript runtime library is available at npm:

npm install kaitai-struct

Code

See the usage examples in the JavaScript notes.

Parse structure from an ArrayBuffer:

var arrayBuffer = ...;
var data = new S3m(new KaitaiStream(arrayBuffer));

After that, one can get various attributes from the structure by accessing fields or properties like:

data.numOrders // => Number of orders in a song

JavaScript source code to parse Scream Tracker 3 module

S3m.js

// This is a generated file! Please edit source .ksy file and use kaitai-struct-compiler to rebuild

(function (root, factory) {
  if (typeof define === 'function' && define.amd) {
    define(['kaitai-struct/KaitaiStream'], factory);
  } else if (typeof module === 'object' && module.exports) {
    module.exports = factory(require('kaitai-struct/KaitaiStream'));
  } else {
    root.S3m = factory(root.KaitaiStream);
  }
}(this, function (KaitaiStream) {
/**
 * Scream Tracker 3 module is a tracker music file format that, as all
 * tracker music, bundles both sound samples and instructions on which
 * notes to play. It originates from a Scream Tracker 3 music editor
 * (1994) by Future Crew, derived from original Scream Tracker 2 (.stm)
 * module format.
 * 
 * Instrument descriptions in S3M format allow to use either digital
 * samples or setup and control AdLib (OPL2) synth.
 * 
 * Music is organized in so called `patterns`. "Pattern" is a generally
 * a 64-row long table, which instructs which notes to play on which
 * time measure. "Patterns" are played one-by-one in a sequence
 * determined by `orders`, which is essentially an array of pattern IDs
 * - this way it's possible to reuse certain patterns more than once
 * for repetitive musical phrases.
 * @see {@link http://hackipedia.org/browse.cgi/File%20formats/Music%20tracker/S3M%2c%20ScreamTracker%203/Scream%20Tracker%203.20%20by%20Future%20Crew.txt|Source}
 */

var S3m = (function() {
  function S3m(_io, _parent, _root) {
    this._io = _io;
    this._parent = _parent;
    this._root = _root || this;

    this._read();
  }
  S3m.prototype._read = function() {
    this.songName = KaitaiStream.bytesTerminate(this._io.readBytes(28), 0, false);
    this.magic1 = this._io.readBytes(1);
    if (!((KaitaiStream.byteArrayCompare(this.magic1, [26]) == 0))) {
      throw new KaitaiStream.ValidationNotEqualError([26], this.magic1, this._io, "/seq/1");
    }
    this.fileType = this._io.readU1();
    this.reserved1 = this._io.readBytes(2);
    this.numOrders = this._io.readU2le();
    this.numInstruments = this._io.readU2le();
    this.numPatterns = this._io.readU2le();
    this.flags = this._io.readU2le();
    this.version = this._io.readU2le();
    this.samplesFormat = this._io.readU2le();
    this.magic2 = this._io.readBytes(4);
    if (!((KaitaiStream.byteArrayCompare(this.magic2, [83, 67, 82, 77]) == 0))) {
      throw new KaitaiStream.ValidationNotEqualError([83, 67, 82, 77], this.magic2, this._io, "/seq/10");
    }
    this.globalVolume = this._io.readU1();
    this.initialSpeed = this._io.readU1();
    this.initialTempo = this._io.readU1();
    this.isStereo = this._io.readBitsIntBe(1) != 0;
    this.masterVolume = this._io.readBitsIntBe(7);
    this._io.alignToByte();
    this.ultraClickRemoval = this._io.readU1();
    this.hasCustomPan = this._io.readU1();
    this.reserved2 = this._io.readBytes(8);
    this.ofsSpecial = this._io.readU2le();
    this.channels = new Array(32);
    for (var i = 0; i < 32; i++) {
      this.channels[i] = new Channel(this._io, this, this._root);
    }
    this.orders = this._io.readBytes(this.numOrders);
    this.instruments = new Array(this.numInstruments);
    for (var i = 0; i < this.numInstruments; i++) {
      this.instruments[i] = new InstrumentPtr(this._io, this, this._root);
    }
    this.patterns = new Array(this.numPatterns);
    for (var i = 0; i < this.numPatterns; i++) {
      this.patterns[i] = new PatternPtr(this._io, this, this._root);
    }
    if (this.hasCustomPan == 252) {
      this.channelPans = new Array(32);
      for (var i = 0; i < 32; i++) {
        this.channelPans[i] = new ChannelPan(this._io, this, this._root);
      }
    }
  }

  var ChannelPan = S3m.ChannelPan = (function() {
    function ChannelPan(_io, _parent, _root) {
      this._io = _io;
      this._parent = _parent;
      this._root = _root || this;

      this._read();
    }
    ChannelPan.prototype._read = function() {
      this.reserved1 = this._io.readBitsIntBe(2);
      this.hasCustomPan = this._io.readBitsIntBe(1) != 0;
      this.reserved2 = this._io.readBitsIntBe(1) != 0;
      this.pan = this._io.readBitsIntBe(4);
    }

    /**
     * If true, then use a custom pan setting provided in the `pan`
     * field. If false, the channel would use the default setting
     * (0x7 for mono, 0x3 or 0xc for stereo).
     */

    return ChannelPan;
  })();

  var PatternCell = S3m.PatternCell = (function() {
    function PatternCell(_io, _parent, _root) {
      this._io = _io;
      this._parent = _parent;
      this._root = _root || this;

      this._read();
    }
    PatternCell.prototype._read = function() {
      this.hasFx = this._io.readBitsIntBe(1) != 0;
      this.hasVolume = this._io.readBitsIntBe(1) != 0;
      this.hasNoteAndInstrument = this._io.readBitsIntBe(1) != 0;
      this.channelNum = this._io.readBitsIntBe(5);
      this._io.alignToByte();
      if (this.hasNoteAndInstrument) {
        this.note = this._io.readU1();
      }
      if (this.hasNoteAndInstrument) {
        this.instrument = this._io.readU1();
      }
      if (this.hasVolume) {
        this.volume = this._io.readU1();
      }
      if (this.hasFx) {
        this.fxType = this._io.readU1();
      }
      if (this.hasFx) {
        this.fxValue = this._io.readU1();
      }
    }

    return PatternCell;
  })();

  var PatternCells = S3m.PatternCells = (function() {
    function PatternCells(_io, _parent, _root) {
      this._io = _io;
      this._parent = _parent;
      this._root = _root || this;

      this._read();
    }
    PatternCells.prototype._read = function() {
      this.cells = [];
      var i = 0;
      while (!this._io.isEof()) {
        this.cells.push(new PatternCell(this._io, this, this._root));
        i++;
      }
    }

    return PatternCells;
  })();

  var Channel = S3m.Channel = (function() {
    function Channel(_io, _parent, _root) {
      this._io = _io;
      this._parent = _parent;
      this._root = _root || this;

      this._read();
    }
    Channel.prototype._read = function() {
      this.isDisabled = this._io.readBitsIntBe(1) != 0;
      this.chType = this._io.readBitsIntBe(7);
    }

    /**
     * Channel type (0..7 = left sample channels, 8..15 = right sample channels, 16..31 = AdLib synth channels)
     */

    return Channel;
  })();

  /**
   * Custom 3-byte integer, stored in mixed endian manner.
   */

  var SwappedU3 = S3m.SwappedU3 = (function() {
    function SwappedU3(_io, _parent, _root) {
      this._io = _io;
      this._parent = _parent;
      this._root = _root || this;

      this._read();
    }
    SwappedU3.prototype._read = function() {
      this.hi = this._io.readU1();
      this.lo = this._io.readU2le();
    }
    Object.defineProperty(SwappedU3.prototype, 'value', {
      get: function() {
        if (this._m_value !== undefined)
          return this._m_value;
        this._m_value = (this.lo | (this.hi << 16));
        return this._m_value;
      }
    });

    return SwappedU3;
  })();

  var Pattern = S3m.Pattern = (function() {
    function Pattern(_io, _parent, _root) {
      this._io = _io;
      this._parent = _parent;
      this._root = _root || this;

      this._read();
    }
    Pattern.prototype._read = function() {
      this.size = this._io.readU2le();
      this._raw_body = this._io.readBytes((this.size - 2));
      var _io__raw_body = new KaitaiStream(this._raw_body);
      this.body = new PatternCells(_io__raw_body, this, this._root);
    }

    return Pattern;
  })();

  var PatternPtr = S3m.PatternPtr = (function() {
    function PatternPtr(_io, _parent, _root) {
      this._io = _io;
      this._parent = _parent;
      this._root = _root || this;

      this._read();
    }
    PatternPtr.prototype._read = function() {
      this.paraptr = this._io.readU2le();
    }
    Object.defineProperty(PatternPtr.prototype, 'body', {
      get: function() {
        if (this._m_body !== undefined)
          return this._m_body;
        var _pos = this._io.pos;
        this._io.seek((this.paraptr * 16));
        this._m_body = new Pattern(this._io, this, this._root);
        this._io.seek(_pos);
        return this._m_body;
      }
    });

    return PatternPtr;
  })();

  var InstrumentPtr = S3m.InstrumentPtr = (function() {
    function InstrumentPtr(_io, _parent, _root) {
      this._io = _io;
      this._parent = _parent;
      this._root = _root || this;

      this._read();
    }
    InstrumentPtr.prototype._read = function() {
      this.paraptr = this._io.readU2le();
    }
    Object.defineProperty(InstrumentPtr.prototype, 'body', {
      get: function() {
        if (this._m_body !== undefined)
          return this._m_body;
        var _pos = this._io.pos;
        this._io.seek((this.paraptr * 16));
        this._m_body = new Instrument(this._io, this, this._root);
        this._io.seek(_pos);
        return this._m_body;
      }
    });

    return InstrumentPtr;
  })();

  var Instrument = S3m.Instrument = (function() {
    Instrument.InstTypes = Object.freeze({
      SAMPLE: 1,
      MELODIC: 2,
      BASS_DRUM: 3,
      SNARE_DRUM: 4,
      TOM: 5,
      CYMBAL: 6,
      HIHAT: 7,

      1: "SAMPLE",
      2: "MELODIC",
      3: "BASS_DRUM",
      4: "SNARE_DRUM",
      5: "TOM",
      6: "CYMBAL",
      7: "HIHAT",
    });

    function Instrument(_io, _parent, _root) {
      this._io = _io;
      this._parent = _parent;
      this._root = _root || this;

      this._read();
    }
    Instrument.prototype._read = function() {
      this.type = this._io.readU1();
      this.filename = KaitaiStream.bytesTerminate(this._io.readBytes(12), 0, false);
      switch (this.type) {
      case S3m.Instrument.InstTypes.SAMPLE:
        this.body = new Sampled(this._io, this, this._root);
        break;
      default:
        this.body = new Adlib(this._io, this, this._root);
        break;
      }
      this.tuningHz = this._io.readU4le();
      this.reserved2 = this._io.readBytes(12);
      this.sampleName = KaitaiStream.bytesTerminate(this._io.readBytes(28), 0, false);
      this.magic = this._io.readBytes(4);
      if (!((KaitaiStream.byteArrayCompare(this.magic, [83, 67, 82, 83]) == 0))) {
        throw new KaitaiStream.ValidationNotEqualError([83, 67, 82, 83], this.magic, this._io, "/types/instrument/seq/6");
      }
    }

    var Sampled = Instrument.Sampled = (function() {
      function Sampled(_io, _parent, _root) {
        this._io = _io;
        this._parent = _parent;
        this._root = _root || this;

        this._read();
      }
      Sampled.prototype._read = function() {
        this.paraptrSample = new SwappedU3(this._io, this, this._root);
        this.lenSample = this._io.readU4le();
        this.loopBegin = this._io.readU4le();
        this.loopEnd = this._io.readU4le();
        this.defaultVolume = this._io.readU1();
        this.reserved1 = this._io.readU1();
        this.isPacked = this._io.readU1();
        this.flags = this._io.readU1();
      }
      Object.defineProperty(Sampled.prototype, 'sample', {
        get: function() {
          if (this._m_sample !== undefined)
            return this._m_sample;
          var _pos = this._io.pos;
          this._io.seek((this.paraptrSample.value * 16));
          this._m_sample = this._io.readBytes(this.lenSample);
          this._io.seek(_pos);
          return this._m_sample;
        }
      });

      /**
       * Default volume
       */

      /**
       * 0 = unpacked, 1 = DP30ADPCM packing
       */

      return Sampled;
    })();

    var Adlib = Instrument.Adlib = (function() {
      function Adlib(_io, _parent, _root) {
        this._io = _io;
        this._parent = _parent;
        this._root = _root || this;

        this._read();
      }
      Adlib.prototype._read = function() {
        this.reserved1 = this._io.readBytes(3);
        if (!((KaitaiStream.byteArrayCompare(this.reserved1, [0, 0, 0]) == 0))) {
          throw new KaitaiStream.ValidationNotEqualError([0, 0, 0], this.reserved1, this._io, "/types/instrument/types/adlib/seq/0");
        }
        this._unnamed1 = this._io.readBytes(16);
      }

      return Adlib;
    })();

    return Instrument;
  })();

  /**
   * Number of orders in a song
   */

  /**
   * Number of instruments in a song
   */

  /**
   * Number of patterns in a song
   */

  /**
   * Scream Tracker version that was used to save this file
   */

  /**
   * 1 = signed samples, 2 = unsigned samples
   */

  /**
   * Offset of special data, not used by Scream Tracker directly.
   */

  return S3m;
})();
return S3m;
}));