/*
Copyright (c) 2008, Adobe Systems Incorporated
All rights reserved.

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modification, are permitted provided that the following conditions are
met:

Redistributions of source code must retain the above copyright notice,
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notice, this list of conditions and the following disclaimer in the
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contributors may be used to endorse or promote products derived from
this software without specific prior written permission.

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IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 /*
JPEG encoder ported to JavaScript and optimized by Andreas Ritter, www.bytestrom.eu, 11/2009

Basic GUI blocking jpeg encoder
function JPEGEncoder(quality) {
  var ffloor = Math.floor;
  var YTable = new Array(64);
  var UVTable = new Array(64);
  var fdtbl_Y = new Array(64);
  var fdtbl_UV = new Array(64);
  var YDC_HT;
  var UVDC_HT;
  var YAC_HT;
  var UVAC_HT;
  var bitcode = new Array(65535);
  var category = new Array(65535);
  var outputfDCTQuant = new Array(64);
  var DU = new Array(64);
  var byteout = [];
  var bytenew = 0;
  var bytepos = 7;
  var YDU = new Array(64);
  var UDU = new Array(64);
  var VDU = new Array(64);
  var clt = new Array(256);
  var RGB_YUV_TABLE = new Array(2048);
  var currentQuality;
  var ZigZag = [0, 1, 5, 6, 14, 15, 27, 28, 2, 4, 7, 13, 16, 26, 29, 42, 3, 8, 12, 17, 25, 30, 41, 43, 9, 11, 18, 24, 31, 40, 44, 53, 10, 19, 23, 32, 39, 45, 52, 54, 20, 22, 33, 38, 46, 51, 55, 60, 21, 34, 37, 47, 50, 56, 59, 61, 35, 36, 48, 49, 57, 58, 62, 63];
  var std_dc_luminance_nrcodes = [0, 0, 1, 5, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0];
  var std_dc_luminance_values = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11];
  var std_ac_luminance_nrcodes = [0, 0, 2, 1, 3, 3, 2, 4, 3, 5, 5, 4, 4, 0, 0, 1, 0x7d];
  var std_ac_luminance_values = [0x01, 0x02, 0x03, 0x00, 0x04, 0x11, 0x05, 0x12, 0x21, 0x31, 0x41, 0x06, 0x13, 0x51, 0x61, 0x07, 0x22, 0x71, 0x14, 0x32, 0x81, 0x91, 0xa1, 0x08, 0x23, 0x42, 0xb1, 0xc1, 0x15, 0x52, 0xd1, 0xf0, 0x24, 0x33, 0x62, 0x72, 0x82, 0x09, 0x0a, 0x16, 0x17, 0x18, 0x19, 0x1a, 0x25, 0x26, 0x27, 0x28, 0x29, 0x2a, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x3a, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48, 0x49, 0x4a, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58, 0x59, 0x5a, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69, 0x6a, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79, 0x7a, 0x83, 0x84, 0x85, 0x86, 0x87, 0x88, 0x89, 0x8a, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97, 0x98, 0x99, 0x9a, 0xa2, 0xa3, 0xa4, 0xa5, 0xa6, 0xa7, 0xa8, 0xa9, 0xaa, 0xb2, 0xb3, 0xb4, 0xb5, 0xb6, 0xb7, 0xb8, 0xb9, 0xba, 0xc2, 0xc3, 0xc4, 0xc5, 0xc6, 0xc7, 0xc8, 0xc9, 0xca, 0xd2, 0xd3, 0xd4, 0xd5, 0xd6, 0xd7, 0xd8, 0xd9, 0xda, 0xe1, 0xe2, 0xe3, 0xe4, 0xe5, 0xe6, 0xe7, 0xe8, 0xe9, 0xea, 0xf1, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7, 0xf8, 0xf9, 0xfa];
  var std_dc_chrominance_nrcodes = [0, 0, 3, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0];
  var std_dc_chrominance_values = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11];
  var std_ac_chrominance_nrcodes = [0, 0, 2, 1, 2, 4, 4, 3, 4, 7, 5, 4, 4, 0, 1, 2, 0x77];
  var std_ac_chrominance_values = [0x00, 0x01, 0x02, 0x03, 0x11, 0x04, 0x05, 0x21, 0x31, 0x06, 0x12, 0x41, 0x51, 0x07, 0x61, 0x71, 0x13, 0x22, 0x32, 0x81, 0x08, 0x14, 0x42, 0x91, 0xa1, 0xb1, 0xc1, 0x09, 0x23, 0x33, 0x52, 0xf0, 0x15, 0x62, 0x72, 0xd1, 0x0a, 0x16, 0x24, 0x34, 0xe1, 0x25, 0xf1, 0x17, 0x18, 0x19, 0x1a, 0x26, 0x27, 0x28, 0x29, 0x2a, 0x35, 0x36, 0x37, 0x38, 0x39, 0x3a, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48, 0x49, 0x4a, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58, 0x59, 0x5a, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69, 0x6a, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79, 0x7a, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87, 0x88, 0x89, 0x8a, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97, 0x98, 0x99, 0x9a, 0xa2, 0xa3, 0xa4, 0xa5, 0xa6, 0xa7, 0xa8, 0xa9, 0xaa, 0xb2, 0xb3, 0xb4, 0xb5, 0xb6, 0xb7, 0xb8, 0xb9, 0xba, 0xc2, 0xc3, 0xc4, 0xc5, 0xc6, 0xc7, 0xc8, 0xc9, 0xca, 0xd2, 0xd3, 0xd4, 0xd5, 0xd6, 0xd7, 0xd8, 0xd9, 0xda, 0xe2, 0xe3, 0xe4, 0xe5, 0xe6, 0xe7, 0xe8, 0xe9, 0xea, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7, 0xf8, 0xf9, 0xfa];

  function initQuantTables(sf) {
    var YQT = [16, 11, 10, 16, 24, 40, 51, 61, 12, 12, 14, 19, 26, 58, 60, 55, 14, 13, 16, 24, 40, 57, 69, 56, 14, 17, 22, 29, 51, 87, 80, 62, 18, 22, 37, 56, 68, 109, 103, 77, 24, 35, 55, 64, 81, 104, 113, 92, 49, 64, 78, 87, 103, 121, 120, 101, 72, 92, 95, 98, 112, 100, 103, 99];

    for (var i = 0; i < 64; i++) {
      var t = ffloor((YQT[i] * sf + 50) / 100);

      if (t < 1) {
        t = 1;
      } else if (t > 255) {
        t = 255;
      }

      YTable[ZigZag[i]] = t;
    }

    var UVQT = [17, 18, 24, 47, 99, 99, 99, 99, 18, 21, 26, 66, 99, 99, 99, 99, 24, 26, 56, 99, 99, 99, 99, 99, 47, 66, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99];

    for (var j = 0; j < 64; j++) {
      var u = ffloor((UVQT[j] * sf + 50) / 100);

      if (u < 1) {
        u = 1;
      } else if (u > 255) {
        u = 255;
      }

      UVTable[ZigZag[j]] = u;
    }

    var aasf = [1.0, 1.387039845, 1.306562965, 1.175875602, 1.0, 0.785694958, 0.541196100, 0.275899379];
    var k = 0;

    for (var row = 0; row < 8; row++) {
      for (var col = 0; col < 8; col++) {
        fdtbl_Y[k] = 1.0 / (YTable[ZigZag[k]] * aasf[row] * aasf[col] * 8.0);
        fdtbl_UV[k] = 1.0 / (UVTable[ZigZag[k]] * aasf[row] * aasf[col] * 8.0);
        k++;
      }
    }
  }

  function computeHuffmanTbl(nrcodes, std_table) {
    var codevalue = 0;
    var pos_in_table = 0;
    var HT = new Array();

    for (var k = 1; k <= 16; k++) {
      for (var j = 1; j <= nrcodes[k]; j++) {
        HT[std_table[pos_in_table]] = [];
        HT[std_table[pos_in_table]][0] = codevalue;
        HT[std_table[pos_in_table]][1] = k;
        pos_in_table++;
        codevalue++;
      }

      codevalue *= 2;
    }

    return HT;
  }

  function initHuffmanTbl() {
    YDC_HT = computeHuffmanTbl(std_dc_luminance_nrcodes, std_dc_luminance_values);
    UVDC_HT = computeHuffmanTbl(std_dc_chrominance_nrcodes, std_dc_chrominance_values);
    YAC_HT = computeHuffmanTbl(std_ac_luminance_nrcodes, std_ac_luminance_values);
    UVAC_HT = computeHuffmanTbl(std_ac_chrominance_nrcodes, std_ac_chrominance_values);
  }

  function initCategoryNumber() {
    var nrlower = 1;
    var nrupper = 2;

    for (var cat = 1; cat <= 15; cat++) {
      //Positive numbers
      for (var nr = nrlower; nr < nrupper; nr++) {
        category[32767 + nr] = cat;
        bitcode[32767 + nr] = [];
        bitcode[32767 + nr][1] = cat;
        bitcode[32767 + nr][0] = nr;
      } //Negative numbers


      for (var nrneg = -(nrupper - 1); nrneg <= -nrlower; nrneg++) {
        category[32767 + nrneg] = cat;
        bitcode[32767 + nrneg] = [];
        bitcode[32767 + nrneg][1] = cat;
        bitcode[32767 + nrneg][0] = nrupper - 1 + nrneg;
      }

      nrlower <<= 1;
      nrupper <<= 1;
    }
  }

  function initRGBYUVTable() {
    for (var i = 0; i < 256; i++) {
      RGB_YUV_TABLE[i] = 19595 * i;
      RGB_YUV_TABLE[i + 256 >> 0] = 38470 * i;
      RGB_YUV_TABLE[i + 512 >> 0] = 7471 * i + 0x8000;
      RGB_YUV_TABLE[i + 768 >> 0] = -11059 * i;
      RGB_YUV_TABLE[i + 1024 >> 0] = -21709 * i;
      RGB_YUV_TABLE[i + 1280 >> 0] = 32768 * i + 0x807FFF;
      RGB_YUV_TABLE[i + 1536 >> 0] = -27439 * i;
      RGB_YUV_TABLE[i + 1792 >> 0] = -5329 * i;
    }
  } // IO functions


  function writeBits(bs) {
    var value = bs[0];
    var posval = bs[1] - 1;

    while (posval >= 0) {
      if (value & 1 << posval) {
        bytenew |= 1 << bytepos;
      }

      posval--;
      bytepos--;

      if (bytepos < 0) {
        if (bytenew == 0xFF) {
          writeByte(0xFF);
          writeByte(0);
        } else {
          writeByte(bytenew);
        }

        bytepos = 7;
        bytenew = 0;
      }
    }
  }

  function writeByte(value) {
    //byteout.push(clt[value]); // write char directly instead of converting later
    byteout.push(value);
  }

  function writeWord(value) {
    writeByte(value >> 8 & 0xFF);
    writeByte(value & 0xFF);
  } // DCT & quantization core


  function fDCTQuant(data, fdtbl) {
    var d0, d1, d2, d3, d4, d5, d6, d7;
    /* Pass 1: process rows. */

    var dataOff = 0;
    var i;
    var I8 = 8;
    var I64 = 64;

    for (i = 0; i < I8; ++i) {
      d0 = data[dataOff];
      d1 = data[dataOff + 1];
      d2 = data[dataOff + 2];
      d3 = data[dataOff + 3];
      d4 = data[dataOff + 4];
      d5 = data[dataOff + 5];
      d6 = data[dataOff + 6];
      d7 = data[dataOff + 7];
      var tmp0 = d0 + d7;
      var tmp7 = d0 - d7;
      var tmp1 = d1 + d6;
      var tmp6 = d1 - d6;
      var tmp2 = d2 + d5;
      var tmp5 = d2 - d5;
      var tmp3 = d3 + d4;
      var tmp4 = d3 - d4;
      /* Even part */

      var tmp10 = tmp0 + tmp3;
      /* phase 2 */

      var tmp13 = tmp0 - tmp3;
      var tmp11 = tmp1 + tmp2;
      var tmp12 = tmp1 - tmp2;
      data[dataOff] = tmp10 + tmp11;
      /* phase 3 */

      data[dataOff + 4] = tmp10 - tmp11;
      var z1 = (tmp12 + tmp13) * 0.707106781;
      /* c4 */

      data[dataOff + 2] = tmp13 + z1;
      /* phase 5 */

      data[dataOff + 6] = tmp13 - z1;
      /* Odd part */

      tmp10 = tmp4 + tmp5;
      /* phase 2 */

      tmp11 = tmp5 + tmp6;
      tmp12 = tmp6 + tmp7;
      /* The rotator is modified from fig 4-8 to avoid extra negations. */

      var z5 = (tmp10 - tmp12) * 0.382683433;
      /* c6 */

      var z2 = 0.541196100 * tmp10 + z5;
      /* c2-c6 */

      var z4 = 1.306562965 * tmp12 + z5;
      /* c2+c6 */

      var z3 = tmp11 * 0.707106781;
      /* c4 */

      var z11 = tmp7 + z3;
      /* phase 5 */

      var z13 = tmp7 - z3;
      data[dataOff + 5] = z13 + z2;
      /* phase 6 */

      data[dataOff + 3] = z13 - z2;
      data[dataOff + 1] = z11 + z4;
      data[dataOff + 7] = z11 - z4;
      dataOff += 8;
      /* advance pointer to next row */
    }
    /* Pass 2: process columns. */


    dataOff = 0;

    for (i = 0; i < I8; ++i) {
      d0 = data[dataOff];
      d1 = data[dataOff + 8];
      d2 = data[dataOff + 16];
      d3 = data[dataOff + 24];
      d4 = data[dataOff + 32];
      d5 = data[dataOff + 40];
      d6 = data[dataOff + 48];
      d7 = data[dataOff + 56];
      var tmp0p2 = d0 + d7;
      var tmp7p2 = d0 - d7;
      var tmp1p2 = d1 + d6;
      var tmp6p2 = d1 - d6;
      var tmp2p2 = d2 + d5;
      var tmp5p2 = d2 - d5;
      var tmp3p2 = d3 + d4;
      var tmp4p2 = d3 - d4;
      /* Even part */

      var tmp10p2 = tmp0p2 + tmp3p2;
      /* phase 2 */

      var tmp13p2 = tmp0p2 - tmp3p2;
      var tmp11p2 = tmp1p2 + tmp2p2;
      var tmp12p2 = tmp1p2 - tmp2p2;
      data[dataOff] = tmp10p2 + tmp11p2;
      /* phase 3 */

      data[dataOff + 32] = tmp10p2 - tmp11p2;
      var z1p2 = (tmp12p2 + tmp13p2) * 0.707106781;
      /* c4 */

      data[dataOff + 16] = tmp13p2 + z1p2;
      /* phase 5 */

      data[dataOff + 48] = tmp13p2 - z1p2;
      /* Odd part */

      tmp10p2 = tmp4p2 + tmp5p2;
      /* phase 2 */

      tmp11p2 = tmp5p2 + tmp6p2;
      tmp12p2 = tmp6p2 + tmp7p2;
      /* The rotator is modified from fig 4-8 to avoid extra negations. */

      var z5p2 = (tmp10p2 - tmp12p2) * 0.382683433;
      /* c6 */

      var z2p2 = 0.541196100 * tmp10p2 + z5p2;
      /* c2-c6 */

      var z4p2 = 1.306562965 * tmp12p2 + z5p2;
      /* c2+c6 */

      var z3p2 = tmp11p2 * 0.707106781;
      /* c4 */

      var z11p2 = tmp7p2 + z3p2;
      /* phase 5 */

      var z13p2 = tmp7p2 - z3p2;
      data[dataOff + 40] = z13p2 + z2p2;
      /* phase 6 */

      data[dataOff + 24] = z13p2 - z2p2;
      data[dataOff + 8] = z11p2 + z4p2;
      data[dataOff + 56] = z11p2 - z4p2;
      dataOff++;
      /* advance pointer to next column */
    } // Quantize/descale the coefficients


    var fDCTQuant;

    for (i = 0; i < I64; ++i) {
      // Apply the quantization and scaling factor & Round to nearest integer
      fDCTQuant = data[i] * fdtbl[i];
      outputfDCTQuant[i] = fDCTQuant > 0.0 ? fDCTQuant + 0.5 | 0 : fDCTQuant - 0.5 | 0; //outputfDCTQuant[i] = fround(fDCTQuant);
    }

    return outputfDCTQuant;
  }

  function writeAPP0() {
    writeWord(0xFFE0); // marker

    writeWord(16); // length

    writeByte(0x4A); // J

    writeByte(0x46); // F

    writeByte(0x49); // I

    writeByte(0x46); // F

    writeByte(0); // = "JFIF",'\0'

    writeByte(1); // versionhi

    writeByte(1); // versionlo

    writeByte(0); // xyunits

    writeWord(1); // xdensity

    writeWord(1); // ydensity

    writeByte(0); // thumbnwidth

    writeByte(0); // thumbnheight
  }

  function writeSOF0(width, height) {
    writeWord(0xFFC0); // marker

    writeWord(17); // length, truecolor YUV JPG

    writeByte(8); // precision

    writeWord(height);
    writeWord(width);
    writeByte(3); // nrofcomponents

    writeByte(1); // IdY

    writeByte(0x11); // HVY

    writeByte(0); // QTY

    writeByte(2); // IdU

    writeByte(0x11); // HVU

    writeByte(1); // QTU

    writeByte(3); // IdV

    writeByte(0x11); // HVV

    writeByte(1); // QTV
  }

  function writeDQT() {
    writeWord(0xFFDB); // marker

    writeWord(132); // length

    writeByte(0);

    for (var i = 0; i < 64; i++) {
      writeByte(YTable[i]);
    }

    writeByte(1);

    for (var j = 0; j < 64; j++) {
      writeByte(UVTable[j]);
    }
  }

  function writeDHT() {
    writeWord(0xFFC4); // marker

    writeWord(0x01A2); // length

    writeByte(0); // HTYDCinfo

    for (var i = 0; i < 16; i++) {
      writeByte(std_dc_luminance_nrcodes[i + 1]);
    }

    for (var j = 0; j <= 11; j++) {
      writeByte(std_dc_luminance_values[j]);
    }

    writeByte(0x10); // HTYACinfo

    for (var k = 0; k < 16; k++) {
      writeByte(std_ac_luminance_nrcodes[k + 1]);
    }

    for (var l = 0; l <= 161; l++) {
      writeByte(std_ac_luminance_values[l]);
    }

    writeByte(1); // HTUDCinfo

    for (var m = 0; m < 16; m++) {
      writeByte(std_dc_chrominance_nrcodes[m + 1]);
    }

    for (var n = 0; n <= 11; n++) {
      writeByte(std_dc_chrominance_values[n]);
    }

    writeByte(0x11); // HTUACinfo

    for (var o = 0; o < 16; o++) {
      writeByte(std_ac_chrominance_nrcodes[o + 1]);
    }

    for (var p = 0; p <= 161; p++) {
      writeByte(std_ac_chrominance_values[p]);
    }
  }

  function writeSOS() {
    writeWord(0xFFDA); // marker

    writeWord(12); // length

    writeByte(3); // nrofcomponents

    writeByte(1); // IdY

    writeByte(0); // HTY

    writeByte(2); // IdU

    writeByte(0x11); // HTU

    writeByte(3); // IdV

    writeByte(0x11); // HTV

    writeByte(0); // Ss

    writeByte(0x3f); // Se

    writeByte(0); // Bf
  }

  function processDU(CDU, fdtbl, DC, HTDC, HTAC) {
    var EOB = HTAC[0x00];
    var M16zeroes = HTAC[0xF0];
    var pos;
    var I16 = 16;
    var I63 = 63;
    var I64 = 64;
    var DU_DCT = fDCTQuant(CDU, fdtbl); //ZigZag reorder

    for (var j = 0; j < I64; ++j) {
      DU[ZigZag[j]] = DU_DCT[j];
    }

    var Diff = DU[0] - DC;
    DC = DU[0]; //Encode DC

    if (Diff == 0) {
      writeBits(HTDC[0]); // Diff might be 0
    } else {
      pos = 32767 + Diff;
      writeBits(HTDC[category[pos]]);
      writeBits(bitcode[pos]);
    } //Encode ACs


    var end0pos = 63; // was const... which is crazy

    for (; end0pos > 0 && DU[end0pos] == 0; end0pos--) {}

    if (end0pos == 0) {
      writeBits(EOB);
      return DC;
    }

    var i = 1;
    var lng;

    while (i <= end0pos) {
      var startpos = i;

      for (; DU[i] == 0 && i <= end0pos; ++i) {}

      var nrzeroes = i - startpos;

      if (nrzeroes >= I16) {
        lng = nrzeroes >> 4;

        for (var nrmarker = 1; nrmarker <= lng; ++nrmarker) {
          writeBits(M16zeroes);
        }

        nrzeroes = nrzeroes & 0xF;
      }

      pos = 32767 + DU[i];
      writeBits(HTAC[(nrzeroes << 4) + category[pos]]);
      writeBits(bitcode[pos]);
      i++;
    }

    if (end0pos != I63) {
      writeBits(EOB);
    }

    return DC;
  }

  function initCharLookupTable() {
    var sfcc = String.fromCharCode;

    for (var i = 0; i < 256; i++) {
      ///// ACHTUNG // 255
      clt[i] = sfcc(i);
    }
  }

  this.encode = function (image, quality) // image data object
  {
    var time_start = new Date().getTime();
    if (quality) setQuality(quality); // Initialize bit writer

    byteout = new Array();
    bytenew = 0;
    bytepos = 7; // Add JPEG headers

    writeWord(0xFFD8); // SOI

    writeAPP0();
    writeDQT();
    writeSOF0(image.width, image.height);
    writeDHT();
    writeSOS(); // Encode 8x8 macroblocks

    var DCY = 0;
    var DCU = 0;
    var DCV = 0;
    bytenew = 0;
    bytepos = 7;
    this.encode.displayName = "_encode_";
    var imageData = image.data;
    var width = image.width;
    var height = image.height;
    var quadWidth = width * 4;
    var x,
        y = 0;
    var r, g, b;
    var start, p, col, row, pos;

    while (y < height) {
      x = 0;

      while (x < quadWidth) {
        start = quadWidth * y + x;
        p = start;
        col = -1;
        row = 0;

        for (pos = 0; pos < 64; pos++) {
          row = pos >> 3; // /8

          col = (pos & 7) * 4; // %8

          p = start + row * quadWidth + col;

          if (y + row >= height) {
            // padding bottom
            p -= quadWidth * (y + 1 + row - height);
          }

          if (x + col >= quadWidth) {
            // padding right	
            p -= x + col - quadWidth + 4;
          }

          r = imageData[p++];
          g = imageData[p++];
          b = imageData[p++];
          /* // calculate YUV values dynamically
          YDU[pos]=((( 0.29900)*r+( 0.58700)*g+( 0.11400)*b))-128; //-0x80
          UDU[pos]=(((-0.16874)*r+(-0.33126)*g+( 0.50000)*b));
          VDU[pos]=((( 0.50000)*r+(-0.41869)*g+(-0.08131)*b));
          */
          // use lookup table (slightly faster)

          YDU[pos] = (RGB_YUV_TABLE[r] + RGB_YUV_TABLE[g + 256 >> 0] + RGB_YUV_TABLE[b + 512 >> 0] >> 16) - 128;
          UDU[pos] = (RGB_YUV_TABLE[r + 768 >> 0] + RGB_YUV_TABLE[g + 1024 >> 0] + RGB_YUV_TABLE[b + 1280 >> 0] >> 16) - 128;
          VDU[pos] = (RGB_YUV_TABLE[r + 1280 >> 0] + RGB_YUV_TABLE[g + 1536 >> 0] + RGB_YUV_TABLE[b + 1792 >> 0] >> 16) - 128;
        }

        DCY = processDU(YDU, fdtbl_Y, DCY, YDC_HT, YAC_HT);
        DCU = processDU(UDU, fdtbl_UV, DCU, UVDC_HT, UVAC_HT);
        DCV = processDU(VDU, fdtbl_UV, DCV, UVDC_HT, UVAC_HT);
        x += 32;
      }

      y += 8;
    } ////////////////////////////////////////////////////////////////
    // Do the bit alignment of the EOI marker


    if (bytepos >= 0) {
      var fillbits = [];
      fillbits[1] = bytepos + 1;
      fillbits[0] = (1 << bytepos + 1) - 1;
      writeBits(fillbits);
    }

    writeWord(0xFFD9); //EOI

    return new Uint8Array(byteout);
  };

  function setQuality(quality) {
    if (quality <= 0) {
      quality = 1;
    }

    if (quality > 100) {
      quality = 100;
    }

    if (currentQuality == quality) return; // don't recalc if unchanged

    var sf = 0;

    if (quality < 50) {
      sf = Math.floor(5000 / quality);
    } else {
      sf = Math.floor(200 - quality * 2);
    }

    initQuantTables(sf);
    currentQuality = quality; //console.log('Quality set to: '+quality +'%');
  }

  function init() {
    var time_start = new Date().getTime();
    if (!quality) quality = 50; // Create tables

    initCharLookupTable();
    initHuffmanTbl();
    initCategoryNumber();
    initRGBYUVTable();
    setQuality(quality);
    var duration = new Date().getTime() - time_start; //console.log('Initialization '+ duration + 'ms');
  }

  init();
}