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/* |
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Copyright (c) 2008, Adobe Systems Incorporated |
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All rights reserved. |
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|
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Redistribution and use in source and binary forms, with or without |
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modification, are permitted provided that the following conditions are |
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met: |
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|
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* Redistributions of source code must retain the above copyright notice, |
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this list of conditions and the following disclaimer. |
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|
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* Redistributions in binary form must reproduce the above copyright |
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notice, this list of conditions and the following disclaimer in the |
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documentation and/or other materials provided with the distribution. |
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|
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* Neither the name of Adobe Systems Incorporated nor the names of its |
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contributors may be used to endorse or promote products derived from |
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this software without specific prior written permission. |
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|
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS |
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IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, |
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THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR |
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PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR |
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CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, |
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EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, |
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PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR |
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PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF |
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LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING |
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NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS |
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SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
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*/ |
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package com.adobe.images |
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{ |
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import flash.geom.*; |
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import flash.display.*; |
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import flash.utils.*; |
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|
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/** |
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* Class that converts BitmapData into a valid JPEG |
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*/ |
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public class JPGEncoder |
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{ |
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|
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// Static table initialization |
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|
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private var ZigZag:Array = [ |
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0, 1, 5, 6,14,15,27,28, |
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2, 4, 7,13,16,26,29,42, |
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3, 8,12,17,25,30,41,43, |
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9,11,18,24,31,40,44,53, |
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10,19,23,32,39,45,52,54, |
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20,22,33,38,46,51,55,60, |
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21,34,37,47,50,56,59,61, |
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35,36,48,49,57,58,62,63 |
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]; |
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|
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private var YTable:Array = new Array(64); |
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private var UVTable:Array = new Array(64); |
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private var fdtbl_Y:Array = new Array(64); |
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private var fdtbl_UV:Array = new Array(64); |
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|
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private function initQuantTables(sf:int):void |
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{ |
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var i:int; |
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var t:Number; |
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var YQT:Array = [ |
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16, 11, 10, 16, 24, 40, 51, 61, |
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12, 12, 14, 19, 26, 58, 60, 55, |
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14, 13, 16, 24, 40, 57, 69, 56, |
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14, 17, 22, 29, 51, 87, 80, 62, |
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18, 22, 37, 56, 68,109,103, 77, |
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24, 35, 55, 64, 81,104,113, 92, |
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49, 64, 78, 87,103,121,120,101, |
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72, 92, 95, 98,112,100,103, 99 |
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]; |
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for (i = 0; i < 64; i++) { |
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t = Math.floor((YQT[i]*sf+50)/100); |
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if (t < 1) { |
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t = 1; |
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} else if (t > 255) { |
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t = 255; |
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} |
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YTable[ZigZag[i]] = t; |
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} |
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var UVQT:Array = [ |
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17, 18, 24, 47, 99, 99, 99, 99, |
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18, 21, 26, 66, 99, 99, 99, 99, |
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24, 26, 56, 99, 99, 99, 99, 99, |
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47, 66, 99, 99, 99, 99, 99, 99, |
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99, 99, 99, 99, 99, 99, 99, 99, |
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99, 99, 99, 99, 99, 99, 99, 99, |
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99, 99, 99, 99, 99, 99, 99, 99, |
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99, 99, 99, 99, 99, 99, 99, 99 |
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]; |
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for (i = 0; i < 64; i++) { |
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t = Math.floor((UVQT[i]*sf+50)/100); |
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if (t < 1) { |
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t = 1; |
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} else if (t > 255) { |
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t = 255; |
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} |
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UVTable[ZigZag[i]] = t; |
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} |
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var aasf:Array = [ |
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1.0, 1.387039845, 1.306562965, 1.175875602, |
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1.0, 0.785694958, 0.541196100, 0.275899379 |
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]; |
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i = 0; |
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for (var row:int = 0; row < 8; row++) |
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{ |
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for (var col:int = 0; col < 8; col++) |
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{ |
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fdtbl_Y[i] = (1.0 / (YTable [ZigZag[i]] * aasf[row] * aasf[col] * 8.0)); |
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fdtbl_UV[i] = (1.0 / (UVTable[ZigZag[i]] * aasf[row] * aasf[col] * 8.0)); |
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i++; |
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} |
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} |
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} |
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|
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private var YDC_HT:Array; |
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private var UVDC_HT:Array; |
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private var YAC_HT:Array; |
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private var UVAC_HT:Array; |
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|
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private function computeHuffmanTbl(nrcodes:Array, std_table:Array):Array |
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{ |
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var codevalue:int = 0; |
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var pos_in_table:int = 0; |
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var HT:Array = new Array(); |
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for (var k:int=1; k<=16; k++) { |
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for (var j:int=1; j<=nrcodes[k]; j++) { |
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HT[std_table[pos_in_table]] = new BitString(); |
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HT[std_table[pos_in_table]].val = codevalue; |
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HT[std_table[pos_in_table]].len = k; |
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pos_in_table++; |
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codevalue++; |
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} |
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codevalue*=2; |
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} |
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return HT; |
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} |
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|
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private var std_dc_luminance_nrcodes:Array = [0,0,1,5,1,1,1,1,1,1,0,0,0,0,0,0,0]; |
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private var std_dc_luminance_values:Array = [0,1,2,3,4,5,6,7,8,9,10,11]; |
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private var std_ac_luminance_nrcodes:Array = [0,0,2,1,3,3,2,4,3,5,5,4,4,0,0,1,0x7d]; |
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private var std_ac_luminance_values:Array = [ |
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0x01,0x02,0x03,0x00,0x04,0x11,0x05,0x12, |
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0x21,0x31,0x41,0x06,0x13,0x51,0x61,0x07, |
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0x22,0x71,0x14,0x32,0x81,0x91,0xa1,0x08, |
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0x23,0x42,0xb1,0xc1,0x15,0x52,0xd1,0xf0, |
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0x24,0x33,0x62,0x72,0x82,0x09,0x0a,0x16, |
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0x17,0x18,0x19,0x1a,0x25,0x26,0x27,0x28, |
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0x29,0x2a,0x34,0x35,0x36,0x37,0x38,0x39, |
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0x3a,0x43,0x44,0x45,0x46,0x47,0x48,0x49, |
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0x4a,0x53,0x54,0x55,0x56,0x57,0x58,0x59, |
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0x5a,0x63,0x64,0x65,0x66,0x67,0x68,0x69, |
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0x6a,0x73,0x74,0x75,0x76,0x77,0x78,0x79, |
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0x7a,0x83,0x84,0x85,0x86,0x87,0x88,0x89, |
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0x8a,0x92,0x93,0x94,0x95,0x96,0x97,0x98, |
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0x99,0x9a,0xa2,0xa3,0xa4,0xa5,0xa6,0xa7, |
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0xa8,0xa9,0xaa,0xb2,0xb3,0xb4,0xb5,0xb6, |
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0xb7,0xb8,0xb9,0xba,0xc2,0xc3,0xc4,0xc5, |
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0xc6,0xc7,0xc8,0xc9,0xca,0xd2,0xd3,0xd4, |
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0xd5,0xd6,0xd7,0xd8,0xd9,0xda,0xe1,0xe2, |
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0xe3,0xe4,0xe5,0xe6,0xe7,0xe8,0xe9,0xea, |
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0xf1,0xf2,0xf3,0xf4,0xf5,0xf6,0xf7,0xf8, |
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0xf9,0xfa |
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]; |
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|
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private var std_dc_chrominance_nrcodes:Array = [0,0,3,1,1,1,1,1,1,1,1,1,0,0,0,0,0]; |
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private var std_dc_chrominance_values:Array = [0,1,2,3,4,5,6,7,8,9,10,11]; |
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private var std_ac_chrominance_nrcodes:Array = [0,0,2,1,2,4,4,3,4,7,5,4,4,0,1,2,0x77]; |
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private var std_ac_chrominance_values:Array = [ |
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0x00,0x01,0x02,0x03,0x11,0x04,0x05,0x21, |
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0x31,0x06,0x12,0x41,0x51,0x07,0x61,0x71, |
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0x13,0x22,0x32,0x81,0x08,0x14,0x42,0x91, |
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0xa1,0xb1,0xc1,0x09,0x23,0x33,0x52,0xf0, |
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0x15,0x62,0x72,0xd1,0x0a,0x16,0x24,0x34, |
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0xe1,0x25,0xf1,0x17,0x18,0x19,0x1a,0x26, |
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0x27,0x28,0x29,0x2a,0x35,0x36,0x37,0x38, |
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0x39,0x3a,0x43,0x44,0x45,0x46,0x47,0x48, |
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0x49,0x4a,0x53,0x54,0x55,0x56,0x57,0x58, |
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0x59,0x5a,0x63,0x64,0x65,0x66,0x67,0x68, |
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0x69,0x6a,0x73,0x74,0x75,0x76,0x77,0x78, |
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0x79,0x7a,0x82,0x83,0x84,0x85,0x86,0x87, |
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0x88,0x89,0x8a,0x92,0x93,0x94,0x95,0x96, |
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0x97,0x98,0x99,0x9a,0xa2,0xa3,0xa4,0xa5, |
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0xa6,0xa7,0xa8,0xa9,0xaa,0xb2,0xb3,0xb4, |
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0xb5,0xb6,0xb7,0xb8,0xb9,0xba,0xc2,0xc3, |
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0xc4,0xc5,0xc6,0xc7,0xc8,0xc9,0xca,0xd2, |
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0xd3,0xd4,0xd5,0xd6,0xd7,0xd8,0xd9,0xda, |
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0xe2,0xe3,0xe4,0xe5,0xe6,0xe7,0xe8,0xe9, |
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0xea,0xf2,0xf3,0xf4,0xf5,0xf6,0xf7,0xf8, |
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0xf9,0xfa |
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]; |
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|
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private function initHuffmanTbl():void |
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{ |
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YDC_HT = computeHuffmanTbl(std_dc_luminance_nrcodes,std_dc_luminance_values); |
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UVDC_HT = computeHuffmanTbl(std_dc_chrominance_nrcodes,std_dc_chrominance_values); |
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YAC_HT = computeHuffmanTbl(std_ac_luminance_nrcodes,std_ac_luminance_values); |
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UVAC_HT = computeHuffmanTbl(std_ac_chrominance_nrcodes,std_ac_chrominance_values); |
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} |
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|
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private var bitcode:Array = new Array(65535); |
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private var category:Array = new Array(65535); |
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|
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private function initCategoryNumber():void |
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{ |
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var nrlower:int = 1; |
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var nrupper:int = 2; |
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var nr:int; |
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for (var cat:int=1; cat<=15; cat++) { |
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//Positive numbers |
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for (nr=nrlower; nr<nrupper; nr++) { |
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category[32767+nr] = cat; |
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bitcode[32767+nr] = new BitString(); |
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bitcode[32767+nr].len = cat; |
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bitcode[32767+nr].val = nr; |
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} |
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//Negative numbers |
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for (nr=-(nrupper-1); nr<=-nrlower; nr++) { |
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category[32767+nr] = cat; |
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bitcode[32767+nr] = new BitString(); |
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bitcode[32767+nr].len = cat; |
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bitcode[32767+nr].val = nrupper-1+nr; |
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} |
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nrlower <<= 1; |
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nrupper <<= 1; |
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} |
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} |
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|
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// IO functions |
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|
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private var byteout:ByteArray; |
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private var bytenew:int = 0; |
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private var bytepos:int = 7; |
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|
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private function writeBits(bs:BitString):void |
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{ |
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var value:int = bs.val; |
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var posval:int = bs.len-1; |
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while ( posval >= 0 ) { |
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if (value & uint(1 << posval) ) { |
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bytenew |= uint(1 << bytepos); |
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} |
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posval--; |
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bytepos--; |
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if (bytepos < 0) { |
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if (bytenew == 0xFF) { |
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writeByte(0xFF); |
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writeByte(0); |
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} |
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else { |
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writeByte(bytenew); |
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} |
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bytepos=7; |
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bytenew=0; |
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} |
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} |
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} |
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|
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private function writeByte(value:int):void |
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{ |
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byteout.writeByte(value); |
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} |
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|
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private function writeWord(value:int):void |
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{ |
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writeByte((value>>8)&0xFF); |
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writeByte((value )&0xFF); |
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} |
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|
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// DCT & quantization core |
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|
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private function fDCTQuant(data:Array, fdtbl:Array):Array |
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{ |
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var tmp0:Number, tmp1:Number, tmp2:Number, tmp3:Number, tmp4:Number, tmp5:Number, tmp6:Number, tmp7:Number; |
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var tmp10:Number, tmp11:Number, tmp12:Number, tmp13:Number; |
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var z1:Number, z2:Number, z3:Number, z4:Number, z5:Number, z11:Number, z13:Number; |
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var i:int; |
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/* Pass 1: process rows. */ |
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var dataOff:int=0; |
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for (i=0; i<8; i++) { |
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tmp0 = data[dataOff+0] + data[dataOff+7]; |
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tmp7 = data[dataOff+0] - data[dataOff+7]; |
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tmp1 = data[dataOff+1] + data[dataOff+6]; |
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tmp6 = data[dataOff+1] - data[dataOff+6]; |
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tmp2 = data[dataOff+2] + data[dataOff+5]; |
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tmp5 = data[dataOff+2] - data[dataOff+5]; |
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tmp3 = data[dataOff+3] + data[dataOff+4]; |
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tmp4 = data[dataOff+3] - data[dataOff+4]; |
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|
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/* Even part */ |
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tmp10 = tmp0 + tmp3; /* phase 2 */ |
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tmp13 = tmp0 - tmp3; |
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tmp11 = tmp1 + tmp2; |
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tmp12 = tmp1 - tmp2; |
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|
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data[dataOff+0] = tmp10 + tmp11; /* phase 3 */ |
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data[dataOff+4] = tmp10 - tmp11; |
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|
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z1 = (tmp12 + tmp13) * 0.707106781; /* c4 */ |
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data[dataOff+2] = tmp13 + z1; /* phase 5 */ |
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data[dataOff+6] = tmp13 - z1; |
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|
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/* Odd part */ |
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tmp10 = tmp4 + tmp5; /* phase 2 */ |
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tmp11 = tmp5 + tmp6; |
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tmp12 = tmp6 + tmp7; |
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|
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/* The rotator is modified from fig 4-8 to avoid extra negations. */ |
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z5 = (tmp10 - tmp12) * 0.382683433; /* c6 */ |
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z2 = 0.541196100 * tmp10 + z5; /* c2-c6 */ |
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z4 = 1.306562965 * tmp12 + z5; /* c2+c6 */ |
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z3 = tmp11 * 0.707106781; /* c4 */ |
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|
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z11 = tmp7 + z3; /* phase 5 */ |
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z13 = tmp7 - z3; |
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|
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data[dataOff+5] = z13 + z2; /* phase 6 */ |
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data[dataOff+3] = z13 - z2; |
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data[dataOff+1] = z11 + z4; |
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data[dataOff+7] = z11 - z4; |
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|
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dataOff += 8; /* advance pointer to next row */ |
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} |
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|
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/* Pass 2: process columns. */ |
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dataOff = 0; |
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for (i=0; i<8; i++) { |
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tmp0 = data[dataOff+ 0] + data[dataOff+56]; |
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tmp7 = data[dataOff+ 0] - data[dataOff+56]; |
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tmp1 = data[dataOff+ 8] + data[dataOff+48]; |
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tmp6 = data[dataOff+ 8] - data[dataOff+48]; |
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tmp2 = data[dataOff+16] + data[dataOff+40]; |
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tmp5 = data[dataOff+16] - data[dataOff+40]; |
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tmp3 = data[dataOff+24] + data[dataOff+32]; |
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tmp4 = data[dataOff+24] - data[dataOff+32]; |
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|
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/* Even part */ |
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tmp10 = tmp0 + tmp3; /* phase 2 */ |
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tmp13 = tmp0 - tmp3; |
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tmp11 = tmp1 + tmp2; |
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tmp12 = tmp1 - tmp2; |
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|
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data[dataOff+ 0] = tmp10 + tmp11; /* phase 3 */ |
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data[dataOff+32] = tmp10 - tmp11; |
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|
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z1 = (tmp12 + tmp13) * 0.707106781; /* c4 */ |
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data[dataOff+16] = tmp13 + z1; /* phase 5 */ |
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data[dataOff+48] = tmp13 - z1; |
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|
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/* Odd part */ |
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tmp10 = tmp4 + tmp5; /* phase 2 */ |
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tmp11 = tmp5 + tmp6; |
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tmp12 = tmp6 + tmp7; |
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|
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/* The rotator is modified from fig 4-8 to avoid extra negations. */ |
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z5 = (tmp10 - tmp12) * 0.382683433; /* c6 */ |
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z2 = 0.541196100 * tmp10 + z5; /* c2-c6 */ |
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z4 = 1.306562965 * tmp12 + z5; /* c2+c6 */ |
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z3 = tmp11 * 0.707106781; /* c4 */ |
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|
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z11 = tmp7 + z3; /* phase 5 */ |
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z13 = tmp7 - z3; |
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|
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data[dataOff+40] = z13 + z2; /* phase 6 */ |
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data[dataOff+24] = z13 - z2; |
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data[dataOff+ 8] = z11 + z4; |
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data[dataOff+56] = z11 - z4; |
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|
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dataOff++; /* advance pointer to next column */ |
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} |
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|
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// Quantize/descale the coefficients |
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for (i=0; i<64; i++) { |
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// Apply the quantization and scaling factor & Round to nearest integer |
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data[i] = Math.round((data[i]*fdtbl[i])); |
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} |
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return data; |
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} |
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|
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// Chunk writing |
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|
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private function writeAPP0():void |
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{ |
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writeWord(0xFFE0); // marker |
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writeWord(16); // length |
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writeByte(0x4A); // J |
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writeByte(0x46); // F |
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writeByte(0x49); // I |
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writeByte(0x46); // F |
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writeByte(0); // = "JFIF",'\0' |
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writeByte(1); // versionhi |
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writeByte(1); // versionlo |
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writeByte(0); // xyunits |
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writeWord(1); // xdensity |
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writeWord(1); // ydensity |
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writeByte(0); // thumbnwidth |
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writeByte(0); // thumbnheight |
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} |
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|
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private function writeSOF0(width:int, height:int):void |
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{ |
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writeWord(0xFFC0); // marker |
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writeWord(17); // length, truecolor YUV JPG |
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writeByte(8); // precision |
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writeWord(height); |
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writeWord(width); |
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writeByte(3); // nrofcomponents |
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writeByte(1); // IdY |
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writeByte(0x11); // HVY |
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writeByte(0); // QTY |
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writeByte(2); // IdU |
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writeByte(0x11); // HVU |
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writeByte(1); // QTU |
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writeByte(3); // IdV |
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writeByte(0x11); // HVV |
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writeByte(1); // QTV |
421 |
} |
422 |
|
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private function writeDQT():void |
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{ |
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writeWord(0xFFDB); // marker |
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writeWord(132); // length |
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writeByte(0); |
428 |
var i:int; |
429 |
for (i=0; i<64; i++) { |
430 |
writeByte(YTable[i]); |
431 |
} |
432 |
writeByte(1); |
433 |
for (i=0; i<64; i++) { |
434 |
writeByte(UVTable[i]); |
435 |
} |
436 |
} |
437 |
|
438 |
private function writeDHT():void |
439 |
{ |
440 |
writeWord(0xFFC4); // marker |
441 |
writeWord(0x01A2); // length |
442 |
var i:int; |
443 |
|
444 |
writeByte(0); // HTYDCinfo |
445 |
for (i=0; i<16; i++) { |
446 |
writeByte(std_dc_luminance_nrcodes[i+1]); |
447 |
} |
448 |
for (i=0; i<=11; i++) { |
449 |
writeByte(std_dc_luminance_values[i]); |
450 |
} |
451 |
|
452 |
writeByte(0x10); // HTYACinfo |
453 |
for (i=0; i<16; i++) { |
454 |
writeByte(std_ac_luminance_nrcodes[i+1]); |
455 |
} |
456 |
for (i=0; i<=161; i++) { |
457 |
writeByte(std_ac_luminance_values[i]); |
458 |
} |
459 |
|
460 |
writeByte(1); // HTUDCinfo |
461 |
for (i=0; i<16; i++) { |
462 |
writeByte(std_dc_chrominance_nrcodes[i+1]); |
463 |
} |
464 |
for (i=0; i<=11; i++) { |
465 |
writeByte(std_dc_chrominance_values[i]); |
466 |
} |
467 |
|
468 |
writeByte(0x11); // HTUACinfo |
469 |
for (i=0; i<16; i++) { |
470 |
writeByte(std_ac_chrominance_nrcodes[i+1]); |
471 |
} |
472 |
for (i=0; i<=161; i++) { |
473 |
writeByte(std_ac_chrominance_values[i]); |
474 |
} |
475 |
} |
476 |
|
477 |
private function writeSOS():void |
478 |
{ |
479 |
writeWord(0xFFDA); // marker |
480 |
writeWord(12); // length |
481 |
writeByte(3); // nrofcomponents |
482 |
writeByte(1); // IdY |
483 |
writeByte(0); // HTY |
484 |
writeByte(2); // IdU |
485 |
writeByte(0x11); // HTU |
486 |
writeByte(3); // IdV |
487 |
writeByte(0x11); // HTV |
488 |
writeByte(0); // Ss |
489 |
writeByte(0x3f); // Se |
490 |
writeByte(0); // Bf |
491 |
} |
492 |
|
493 |
// Core processing |
494 |
private var DU:Array = new Array(64); |
495 |
|
496 |
private function processDU(CDU:Array, fdtbl:Array, DC:Number, HTDC:Array, HTAC:Array):Number |
497 |
{ |
498 |
var EOB:BitString = HTAC[0x00]; |
499 |
var M16zeroes:BitString = HTAC[0xF0]; |
500 |
var i:int; |
501 |
|
502 |
var DU_DCT:Array = fDCTQuant(CDU, fdtbl); |
503 |
//ZigZag reorder |
504 |
for (i=0;i<64;i++) { |
505 |
DU[ZigZag[i]]=DU_DCT[i]; |
506 |
} |
507 |
var Diff:int = DU[0] - DC; DC = DU[0]; |
508 |
//Encode DC |
509 |
if (Diff==0) { |
510 |
writeBits(HTDC[0]); // Diff might be 0 |
511 |
} else { |
512 |
writeBits(HTDC[category[32767+Diff]]); |
513 |
writeBits(bitcode[32767+Diff]); |
514 |
} |
515 |
//Encode ACs |
516 |
var end0pos:int = 63; |
517 |
for (; (end0pos>0)&&(DU[end0pos]==0); end0pos--) { |
518 |
}; |
519 |
//end0pos = first element in reverse order !=0 |
520 |
if ( end0pos == 0) { |
521 |
writeBits(EOB); |
522 |
return DC; |
523 |
} |
524 |
i = 1; |
525 |
while ( i <= end0pos ) { |
526 |
var startpos:int = i; |
527 |
for (; (DU[i]==0) && (i<=end0pos); i++) { |
528 |
} |
529 |
var nrzeroes:int = i-startpos; |
530 |
if ( nrzeroes >= 16 ) { |
531 |
for (var nrmarker:int=1; nrmarker <= nrzeroes/16; nrmarker++) { |
532 |
writeBits(M16zeroes); |
533 |
} |
534 |
nrzeroes = int(nrzeroes&0xF); |
535 |
} |
536 |
writeBits(HTAC[nrzeroes*16+category[32767+DU[i]]]); |
537 |
writeBits(bitcode[32767+DU[i]]); |
538 |
i++; |
539 |
} |
540 |
if ( end0pos != 63 ) { |
541 |
writeBits(EOB); |
542 |
} |
543 |
return DC; |
544 |
} |
545 |
|
546 |
private var YDU:Array = new Array(64); |
547 |
private var UDU:Array = new Array(64); |
548 |
private var VDU:Array = new Array(64); |
549 |
|
550 |
private function RGB2YUV(img:BitmapData, xpos:int, ypos:int):void |
551 |
{ |
552 |
var pos:int=0; |
553 |
for (var y:int=0; y<8; y++) { |
554 |
for (var x:int=0; x<8; x++) { |
555 |
var P:uint = img.getPixel32(xpos+x,ypos+y); |
556 |
var R:Number = Number((P>>16)&0xFF); |
557 |
var G:Number = Number((P>> 8)&0xFF); |
558 |
var B:Number = Number((P )&0xFF); |
559 |
YDU[pos]=((( 0.29900)*R+( 0.58700)*G+( 0.11400)*B))-128; |
560 |
UDU[pos]=(((-0.16874)*R+(-0.33126)*G+( 0.50000)*B)); |
561 |
VDU[pos]=((( 0.50000)*R+(-0.41869)*G+(-0.08131)*B)); |
562 |
pos++; |
563 |
} |
564 |
} |
565 |
} |
566 |
|
567 |
/** |
568 |
* Constructor for JPEGEncoder class |
569 |
* |
570 |
* @param quality The quality level between 1 and 100 that detrmines the |
571 |
* level of compression used in the generated JPEG |
572 |
* @langversion ActionScript 3.0 |
573 |
* @playerversion Flash 9.0 |
574 |
* @tiptext |
575 |
*/ |
576 |
public function JPGEncoder(quality:Number = 50) |
577 |
{ |
578 |
if (quality <= 0) { |
579 |
quality = 1; |
580 |
} |
581 |
if (quality > 100) { |
582 |
quality = 100; |
583 |
} |
584 |
var sf:int = 0; |
585 |
if (quality < 50) { |
586 |
sf = int(5000 / quality); |
587 |
} else { |
588 |
sf = int(200 - quality*2); |
589 |
} |
590 |
// Create tables |
591 |
initHuffmanTbl(); |
592 |
initCategoryNumber(); |
593 |
initQuantTables(sf); |
594 |
} |
595 |
|
596 |
/** |
597 |
* Created a JPEG image from the specified BitmapData |
598 |
* |
599 |
* @param image The BitmapData that will be converted into the JPEG format. |
600 |
* @return a ByteArray representing the JPEG encoded image data. |
601 |
* @langversion ActionScript 3.0 |
602 |
* @playerversion Flash 9.0 |
603 |
* @tiptext |
604 |
*/ |
605 |
public function encode(image:BitmapData):ByteArray |
606 |
{ |
607 |
// Initialize bit writer |
608 |
byteout = new ByteArray(); |
609 |
bytenew=0; |
610 |
bytepos=7; |
611 |
|
612 |
// Add JPEG headers |
613 |
writeWord(0xFFD8); // SOI |
614 |
writeAPP0(); |
615 |
writeDQT(); |
616 |
writeSOF0(image.width,image.height); |
617 |
writeDHT(); |
618 |
writeSOS(); |
619 |
|
620 |
|
621 |
// Encode 8x8 macroblocks |
622 |
var DCY:Number=0; |
623 |
var DCU:Number=0; |
624 |
var DCV:Number=0; |
625 |
bytenew=0; |
626 |
bytepos=7; |
627 |
for (var ypos:int=0; ypos<image.height; ypos+=8) { |
628 |
for (var xpos:int=0; xpos<image.width; xpos+=8) { |
629 |
RGB2YUV(image, xpos, ypos); |
630 |
DCY = processDU(YDU, fdtbl_Y, DCY, YDC_HT, YAC_HT); |
631 |
DCU = processDU(UDU, fdtbl_UV, DCU, UVDC_HT, UVAC_HT); |
632 |
DCV = processDU(VDU, fdtbl_UV, DCV, UVDC_HT, UVAC_HT); |
633 |
} |
634 |
} |
635 |
|
636 |
// Do the bit alignment of the EOI marker |
637 |
if ( bytepos >= 0 ) { |
638 |
var fillbits:BitString = new BitString(); |
639 |
fillbits.len = bytepos+1; |
640 |
fillbits.val = (1<<(bytepos+1))-1; |
641 |
writeBits(fillbits); |
642 |
} |
643 |
|
644 |
writeWord(0xFFD9); //EOI |
645 |
return byteout; |
646 |
} |
647 |
} |
648 |
} |