/*

	Adobe Systems Incorporated(r) Source Code License Agreement

	Copyright(c) 2005 Adobe Systems Incorporated. All rights reserved.

	

	Please read this Source Code License Agreement carefully before using

	the source code.

	

	Adobe Systems Incorporated grants to you a perpetual, worldwide, non-exclusive, 

	no-charge, royalty-free, irrevocable copyright license, to reproduce,

	prepare derivative works of, publicly display, publicly perform, and

	distribute this source code and such derivative works in source or 

	object code form without any attribution requirements.  

	

	The name "Adobe Systems Incorporated" must not be used to endorse or promote products

	derived from the source code without prior written permission.

	

	You agree to indemnify, hold harmless and defend Adobe Systems Incorporated from and

	against any loss, damage, claims or lawsuits, including attorney's 

	fees that arise or result from your use or distribution of the source 

	code.

	

	THIS SOURCE CODE IS PROVIDED "AS IS" AND "WITH ALL FAULTS", WITHOUT 

	ANY TECHNICAL SUPPORT OR ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING,

	BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS

	FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  ALSO, THERE IS NO WARRANTY OF 

	NON-INFRINGEMENT, TITLE OR QUIET ENJOYMENT.  IN NO EVENT SHALL MACROMEDIA

	OR ITS SUPPLIERS 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 SOURCE CODE, EVEN IF

	ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

*/

package com.adobe.images

{

	import flash.geom.*;

	import flash.display.*;

	import flash.utils.*;

	

	/**

	 * Class that converts BitmapData into a valid JPEG

	 */		

	public class JPGEncoder

	{



		// Static table initialization

	

		private var ZigZag:Array = [

			 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

		];

	

		private var YTable:Array = new Array(64);

		private var UVTable:Array = new Array(64);

		private var fdtbl_Y:Array = new Array(64);

		private var fdtbl_UV:Array = new Array(64);

	

		private function initQuantTables(sf:int):void

		{

			var i:int;

			var t:Number;

			var YQT:Array = [

				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 (i = 0; i < 64; i++) {

				t = Math.floor((YQT[i]*sf+50)/100);

				if (t < 1) {

					t = 1;

				} else if (t > 255) {

					t = 255;

				}

				YTable[ZigZag[i]] = t;

			}

			var UVQT:Array = [

				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 (i = 0; i < 64; i++) {

				t = Math.floor((UVQT[i]*sf+50)/100);

				if (t < 1) {

					t = 1;

				} else if (t > 255) {

					t = 255;

				}

				UVTable[ZigZag[i]] = t;

			}

			var aasf:Array = [

				1.0, 1.387039845, 1.306562965, 1.175875602,

				1.0, 0.785694958, 0.541196100, 0.275899379

			];

			i = 0;

			for (var row:int = 0; row < 8; row++)

			{

				for (var col:int = 0; col < 8; col++)

				{

					fdtbl_Y[i]  = (1.0 / (YTable [ZigZag[i]] * aasf[row] * aasf[col] * 8.0));

					fdtbl_UV[i] = (1.0 / (UVTable[ZigZag[i]] * aasf[row] * aasf[col] * 8.0));

					i++;

				}

			}

		}

	

		private var YDC_HT:Array;

		private var UVDC_HT:Array;

		private var YAC_HT:Array;

		private var UVAC_HT:Array;

	

		private function computeHuffmanTbl(nrcodes:Array, std_table:Array):Array

		{

			var codevalue:int = 0;

			var pos_in_table:int = 0;

			var HT:Array = new Array();

			for (var k:int=1; k<=16; k++) {

				for (var j:int=1; j<=nrcodes[k]; j++) {

					HT[std_table[pos_in_table]] = new BitString();

					HT[std_table[pos_in_table]].val = codevalue;

					HT[std_table[pos_in_table]].len = k;

					pos_in_table++;

					codevalue++;

				}

				codevalue*=2;

			}

			return HT;

		}

	

		private var std_dc_luminance_nrcodes:Array = [0,0,1,5,1,1,1,1,1,1,0,0,0,0,0,0,0];

		private var std_dc_luminance_values:Array = [0,1,2,3,4,5,6,7,8,9,10,11];

		private var std_ac_luminance_nrcodes:Array = [0,0,2,1,3,3,2,4,3,5,5,4,4,0,0,1,0x7d];

		private var std_ac_luminance_values:Array = [

			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

		];

	

		private var std_dc_chrominance_nrcodes:Array = [0,0,3,1,1,1,1,1,1,1,1,1,0,0,0,0,0];

		private var std_dc_chrominance_values:Array = [0,1,2,3,4,5,6,7,8,9,10,11];

		private var std_ac_chrominance_nrcodes:Array = [0,0,2,1,2,4,4,3,4,7,5,4,4,0,1,2,0x77];

		private var std_ac_chrominance_values:Array = [

			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

		];

	

		private function initHuffmanTbl():void

		{

			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);

		}

	

		private var bitcode:Array = new Array(65535);

		private var category:Array = new Array(65535);

	

		private function initCategoryNumber():void

		{

			var nrlower:int = 1;

			var nrupper:int = 2;

			var nr:int;

			for (var cat:int=1; cat<=15; cat++) {

				//Positive numbers

				for (nr=nrlower; nr<nrupper; nr++) {

					category[32767+nr] = cat;

					bitcode[32767+nr] = new BitString();

					bitcode[32767+nr].len = cat;

					bitcode[32767+nr].val = nr;

				}

				//Negative numbers

				for (nr=-(nrupper-1); nr<=-nrlower; nr++) {

					category[32767+nr] = cat;

					bitcode[32767+nr] = new BitString();

					bitcode[32767+nr].len = cat;

					bitcode[32767+nr].val = nrupper-1+nr;

				}

				nrlower <<= 1;

				nrupper <<= 1;

			}

		}

	

		// IO functions

	

		private var byteout:ByteArray;

		private var bytenew:int = 0;

		private var bytepos:int = 7;

	

		private function writeBits(bs:BitString):void

		{

			var value:int = bs.val;

			var posval:int = bs.len-1;

			while ( posval >= 0 ) {

				if (value & uint(1 << posval) ) {

					bytenew |= uint(1 << bytepos);

				}

				posval--;

				bytepos--;

				if (bytepos < 0) {

					if (bytenew == 0xFF) {

						writeByte(0xFF);

						writeByte(0);

					}

					else {

						writeByte(bytenew);

					}

					bytepos=7;

					bytenew=0;

				}

			}

		}

	

		private function writeByte(value:int):void

		{

			byteout.writeByte(value);

		}

	

		private function writeWord(value:int):void

		{

			writeByte((value>>8)&0xFF);

			writeByte((value   )&0xFF);

		}

	

		// DCT & quantization core

	

		private function fDCTQuant(data:Array, fdtbl:Array):Array

		{

			var tmp0:Number, tmp1:Number, tmp2:Number, tmp3:Number, tmp4:Number, tmp5:Number, tmp6:Number, tmp7:Number;

			var tmp10:Number, tmp11:Number, tmp12:Number, tmp13:Number;

			var z1:Number, z2:Number, z3:Number, z4:Number, z5:Number, z11:Number, z13:Number;

			var i:int;

			/* Pass 1: process rows. */

			var dataOff:int=0;

			for (i=0; i<8; i++) {

				tmp0 = data[dataOff+0] + data[dataOff+7];

				tmp7 = data[dataOff+0] - data[dataOff+7];

				tmp1 = data[dataOff+1] + data[dataOff+6];

				tmp6 = data[dataOff+1] - data[dataOff+6];

				tmp2 = data[dataOff+2] + data[dataOff+5];

				tmp5 = data[dataOff+2] - data[dataOff+5];

				tmp3 = data[dataOff+3] + data[dataOff+4];

				tmp4 = data[dataOff+3] - data[dataOff+4];

	

				/* Even part */

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

				tmp13 = tmp0 - tmp3;

				tmp11 = tmp1 + tmp2;

				tmp12 = tmp1 - tmp2;

	

				data[dataOff+0] = tmp10 + tmp11; /* phase 3 */

				data[dataOff+4] = tmp10 - tmp11;

	

				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. */

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

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

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

				z3 = tmp11 * 0.707106781; /* c4 */

	

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

				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<8; i++) {

				tmp0 = data[dataOff+ 0] + data[dataOff+56];

				tmp7 = data[dataOff+ 0] - data[dataOff+56];

				tmp1 = data[dataOff+ 8] + data[dataOff+48];

				tmp6 = data[dataOff+ 8] - data[dataOff+48];

				tmp2 = data[dataOff+16] + data[dataOff+40];

				tmp5 = data[dataOff+16] - data[dataOff+40];

				tmp3 = data[dataOff+24] + data[dataOff+32];

				tmp4 = data[dataOff+24] - data[dataOff+32];

	

				/* Even part */

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

				tmp13 = tmp0 - tmp3;

				tmp11 = tmp1 + tmp2;

				tmp12 = tmp1 - tmp2;

	

				data[dataOff+ 0] = tmp10 + tmp11; /* phase 3 */

				data[dataOff+32] = tmp10 - tmp11;

	

				z1 = (tmp12 + tmp13) * 0.707106781; /* c4 */

				data[dataOff+16] = tmp13 + z1; /* phase 5 */

				data[dataOff+48] = 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. */

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

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

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

				z3 = tmp11 * 0.707106781; /* c4 */

	

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

				z13 = tmp7 - z3;

	

				data[dataOff+40] = z13 + z2; /* phase 6 */

				data[dataOff+24] = z13 - z2;

				data[dataOff+ 8] = z11 + z4;

				data[dataOff+56] = z11 - z4;

	

				dataOff++; /* advance pointer to next column */

			}

	

			// Quantize/descale the coefficients

			for (i=0; i<64; i++) {

				// Apply the quantization and scaling factor & Round to nearest integer

				data[i] = Math.round((data[i]*fdtbl[i]));

			}

			return data;

		}

	

		// Chunk writing

	

		private function writeAPP0():void

		{

			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

		}

	

		private function writeSOF0(width:int, height:int):void

		{

			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

		}

	

		private function writeDQT():void

		{

			writeWord(0xFFDB); // marker

			writeWord(132);	   // length

			writeByte(0);

			var i:int;

			for (i=0; i<64; i++) {

				writeByte(YTable[i]);

			}

			writeByte(1);

			for (i=0; i<64; i++) {

				writeByte(UVTable[i]);

			}

		}

	

		private function writeDHT():void

		{

			writeWord(0xFFC4); // marker

			writeWord(0x01A2); // length

			var i:int;

	

			writeByte(0); // HTYDCinfo

			for (i=0; i<16; i++) {

				writeByte(std_dc_luminance_nrcodes[i+1]);

			}

			for (i=0; i<=11; i++) {

				writeByte(std_dc_luminance_values[i]);

			}

	

			writeByte(0x10); // HTYACinfo

			for (i=0; i<16; i++) {

				writeByte(std_ac_luminance_nrcodes[i+1]);

			}

			for (i=0; i<=161; i++) {

				writeByte(std_ac_luminance_values[i]);

			}

	

			writeByte(1); // HTUDCinfo

			for (i=0; i<16; i++) {

				writeByte(std_dc_chrominance_nrcodes[i+1]);

			}

			for (i=0; i<=11; i++) {

				writeByte(std_dc_chrominance_values[i]);

			}

	

			writeByte(0x11); // HTUACinfo

			for (i=0; i<16; i++) {

				writeByte(std_ac_chrominance_nrcodes[i+1]);

			}

			for (i=0; i<=161; i++) {

				writeByte(std_ac_chrominance_values[i]);

			}

		}

	

		private function writeSOS():void

		{

			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

		}

	

		// Core processing

		private var DU:Array = new Array(64);

	

		private function processDU(CDU:Array, fdtbl:Array, DC:Number, HTDC:Array, HTAC:Array):Number

		{

			var EOB:BitString = HTAC[0x00];

			var M16zeroes:BitString = HTAC[0xF0];

			var i:int;

	

			var DU_DCT:Array = fDCTQuant(CDU, fdtbl);

			//ZigZag reorder

			for (i=0;i<64;i++) {

				DU[ZigZag[i]]=DU_DCT[i];

			}

			var Diff:int = DU[0] - DC; DC = DU[0];

			//Encode DC

			if (Diff==0) {

				writeBits(HTDC[0]); // Diff might be 0

			} else {

				writeBits(HTDC[category[32767+Diff]]);

				writeBits(bitcode[32767+Diff]);

			}

			//Encode ACs

			var end0pos:int = 63;

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

			};

			//end0pos = first element in reverse order !=0

			if ( end0pos == 0) {

				writeBits(EOB);

				return DC;

			}

			i = 1;

			while ( i <= end0pos ) {

				var startpos:int = i;

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

				}

				var nrzeroes:int = i-startpos;

				if ( nrzeroes >= 16 ) {

					for (var nrmarker:int=1; nrmarker <= nrzeroes/16; nrmarker++) {

						writeBits(M16zeroes);

					}

					nrzeroes = int(nrzeroes&0xF);

				}

				writeBits(HTAC[nrzeroes*16+category[32767+DU[i]]]);

				writeBits(bitcode[32767+DU[i]]);

				i++;

			}

			if ( end0pos != 63 ) {

				writeBits(EOB);

			}

			return DC;

		}

	

		private var YDU:Array = new Array(64);

		private var UDU:Array = new Array(64);

		private var VDU:Array = new Array(64);

	

		private function RGB2YUV(img:BitmapData, xpos:int, ypos:int):void

		{

			var pos:int=0;

			for (var y:int=0; y<8; y++) {

				for (var x:int=0; x<8; x++) {

					var P:uint = img.getPixel32(xpos+x,ypos+y);

					var R:Number = Number((P>>16)&0xFF);

					var G:Number = Number((P>> 8)&0xFF);

					var B:Number = Number((P    )&0xFF);

					YDU[pos]=((( 0.29900)*R+( 0.58700)*G+( 0.11400)*B))-128;

					UDU[pos]=(((-0.16874)*R+(-0.33126)*G+( 0.50000)*B));

					VDU[pos]=((( 0.50000)*R+(-0.41869)*G+(-0.08131)*B));

					pos++;

				}

			}

		}

	

		/**

		 * Constructor for JPEGEncoder class

		 *

		 * @param quality The quality level between 1 and 100 that detrmines the

		 * level of compression used in the generated JPEG

		 * @langversion ActionScript 3.0

		 * @playerversion Flash 9.0

		 * @tiptext

		 */		

		public function JPGEncoder(quality:Number = 50)

		{

			if (quality <= 0) {

				quality = 1;

			}

			if (quality > 100) {

				quality = 100;

			}

			var sf:int = 0;

			if (quality < 50) {

				sf = int(5000 / quality);

			} else {

				sf = int(200 - quality*2);

			}

			// Create tables

			initHuffmanTbl();

			initCategoryNumber();

			initQuantTables(sf);

		}

	

		/**

		 * Created a JPEG image from the specified BitmapData

		 *

		 * @param image The BitmapData that will be converted into the JPEG format.

		 * @return a ByteArray representing the JPEG encoded image data.

		 * @langversion ActionScript 3.0

		 * @playerversion Flash 9.0

		 * @tiptext

		 */	

		public function encode(image:BitmapData):ByteArray

		{

			// Initialize bit writer

			byteout = new ByteArray();

			bytenew=0;

			bytepos=7;

	

			// Add JPEG headers

			writeWord(0xFFD8); // SOI

			writeAPP0();

			writeDQT();

			writeSOF0(image.width,image.height);

			writeDHT();

			writeSOS();



	

			// Encode 8x8 macroblocks

			var DCY:Number=0;

			var DCU:Number=0;

			var DCV:Number=0;

			bytenew=0;

			bytepos=7;

			for (var ypos:int=0; ypos<image.height; ypos+=8) {

				for (var xpos:int=0; xpos<image.width; xpos+=8) {

					RGB2YUV(image, xpos, ypos);

					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);

				}

			}

	

			// Do the bit alignment of the EOI marker

			if ( bytepos >= 0 ) {

				var fillbits:BitString = new BitString();

				fillbits.len = bytepos+1;

				fillbits.val = (1<<(bytepos+1))-1;

				writeBits(fillbits);

			}

	

			writeWord(0xFFD9); //EOI

			return byteout;

		}

	}

}