post.js

  // libmp3lame function wrappers
  var BUFSIZE = 1024000;
  return {
    // MPEG modes
    STEREO: 0,
    JOINT_STEREO: 1,
    MONO: 3,
    NOT_SET:4,
    // vbr modes
    VBR_OFF:0,
    VBR_MT:1,               /* obsolete, same as vbr_mtrh */
    VBR_RH:2,
    VBR_ABR:3,
    VBR_MTRH:4,

    get_version: Module.cwrap('get_lame_version', 'string'),

    init: Module.cwrap('lame_init', 'number'),
    init_params: Module.cwrap('lame_init_params', 'number', ['number']),

    set_mode: Module.cwrap('lame_set_mode', 'number', ['number', 'number']),
    get_mode: Module.cwrap('lame_get_mode', 'number', ['number']),

    set_num_samples: Module.cwrap('lame_set_num_samples', 'number', ['number', 'number']),
    get_num_samples: Module.cwrap('lame_get_num_samples', 'number', ['number']),

    set_num_channels: Module.cwrap('lame_set_num_channels', 'number', ['number', 'number']),
    get_num_channels: Module.cwrap('lame_get_num_channels', 'number', ['number']),

    set_in_samplerate: Module.cwrap('lame_set_in_samplerate', 'number', ['number', 'number']),
    get_in_samplerate: Module.cwrap('lame_get_in_samplerate', 'number', ['number']),

    set_out_samplerate: Module.cwrap('lame_set_out_samplerate', 'number', ['number', 'number']),
    get_out_samplerate: Module.cwrap('lame_get_out_samplerate', 'number', ['number']),

    set_bitrate: Module.cwrap('lame_set_brate', 'number', ['number', 'number']),
    get_bitrate: Module.cwrap('lame_get_brate', 'number', ['number']),

    set_VBR: Module.cwrap('lame_set_VBR', 'number', ['number', 'number']),
    get_VBR: Module.cwrap('lame_get_VBR', 'number', ['number']),

    set_VBR_q: Module.cwrap('lame_set_VBR_q', 'number', ['number', 'number']),
    get_VBR_q: Module.cwrap('lame_get_VBR_q', 'number', ['number']),

    set_VBR_mean_bitrate_kbps: Module.cwrap('lame_set_VBR_mean_bitrate_kbps', 'number', ['number', 'number']),
    get_VBR_mean_bitrate_kbps: Module.cwrap('lame_get_VBR_mean_bitrate_kbps', 'number', ['number']),

    set_VBR_min_bitrate_kbps: Module.cwrap('lame_set_VBR_min_bitrate_kbps', 'number', ['number', 'number']),
    get_VBR_min_bitrate_kbps: Module.cwrap('lame_get_VBR_min_bitrate_kbps', 'number', ['number']),

    set_VBR_max_bitrate_kbps: Module.cwrap('lame_set_VBR_max_bitrate_kbps', 'number', ['number', 'number']),
    get_VBR_max_bitrate_kbps: Module.cwrap('lame_get_VBR_max_bitrate_kbps', 'number', ['number']),

    encode_buffer_ieee_float: function (handle, channel_l, channel_r) {
      BUFSIZE = channel_l.length * 4;
      var outbuf = _malloc(BUFSIZE);
      var inbuf_l = _malloc(channel_l.length * 4);
      var inbuf_r = _malloc(channel_r.length * 4);
      for (var i = 0; i < channel_l.length; i++) {
        setValue(inbuf_l + (i * 4), channel_l[i], 'float');
      }
      for (var i = 0; i < channel_r.length; i++) {
        setValue(inbuf_r + (i * 4), channel_r[i], 'float');
      }
      var nread = Module.ccall('lame_encode_buffer_ieee_float', 'number', ['number', 'number', 'number', 'number', 'number', 'number'], [handle, inbuf_l, inbuf_r, channel_l.length, outbuf, BUFSIZE]);
      var arraybuf = new ArrayBuffer(nread);
      var retdata = new Uint8Array(arraybuf);
      retdata.set(HEAPU8.subarray(outbuf, outbuf + nread));
      _free(outbuf);
      _free(inbuf_l);
      _free(inbuf_r);
      return { size: nread, data: retdata };
    },

    encode_flush: function (handle) {
      var outbuf = _malloc(BUFSIZE);
      var nread = Module.ccall('lame_encode_flush', 'number', ['number', 'number', 'number'], [handle, outbuf, BUFSIZE]);
      var arraybuf = new ArrayBuffer(nread);
      var retdata = new Uint8Array(arraybuf);
      retdata.set(HEAPU8.subarray(outbuf, outbuf + nread));
      _free(outbuf);
      return { size: nread, data: retdata };
    },

    close: Module.cwrap('lame_close', 'number', ['number'])
  };

})();

self.Lame = Lame; // make Lame accessible to other webworker scripts.