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/* idct.c, inverse fast discrete cosine transform */ |
/***************************************************************************** |
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/* Copyright (C) 1996, MPEG Software Simulation Group. All Rights Reserved. */ |
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/* |
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* Disclaimer of Warranty |
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* |
* |
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* These software programs are available to the user without any license fee or |
* XVID MPEG-4 VIDEO CODEC |
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* royalty on an "as is" basis. The MPEG Software Simulation Group disclaims |
* - inverse fast disrete cosine transformation - integer C version |
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* any and all warranties, whether express, implied, or statuary, including any |
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* implied warranties or merchantability or of fitness for a particular |
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* purpose. In no event shall the copyright-holder be liable for any |
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* incidental, punitive, or consequential damages of any kind whatsoever |
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* arising from the use of these programs. |
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* |
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* This disclaimer of warranty extends to the user of these programs and user's |
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* customers, employees, agents, transferees, successors, and assigns. |
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* |
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* The MPEG Software Simulation Group does not represent or warrant that the |
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* programs furnished hereunder are free of infringement of any third-party |
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* patents. |
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* |
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* Commercial implementations of MPEG-1 and MPEG-2 video, including shareware, |
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* are subject to royalty fees to patent holders. Many of these patents are |
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* general enough such that they are unavoidable regardless of implementation |
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* design. |
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* |
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* MPEG2AVI |
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* -------- |
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* v0.16B33 renamed the initialization function to init_idct_int32() |
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* v0.16B32 removed the unused idct_row() and idct_col() functions |
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* v0.16B3 changed var declarations to static, to enforce data align |
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* v0.16B22 idct_FAST() renamed to idct_int32() |
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* also merged idct_FAST() into a single function, to help VC++ |
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* optimize it. |
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* |
* |
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* v0.14 changed int to long, to avoid confusion when compiling on x86 |
* These routines are from Independent JPEG Group's free JPEG software |
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* platform ( in VC++ "int" -> 32bits ) |
* Copyright (C) 1991-1998, Thomas G. Lane (see the file README.IJG) |
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*/ |
* |
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* This file is part of XviD, a free MPEG-4 video encoder/decoder |
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* |
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* XviD is free software; you can redistribute it and/or modify it |
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* under the terms of the GNU General Public License as published by |
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* the Free Software Foundation; either version 2 of the License, or |
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* (at your option) any later version. |
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* |
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* This program is distributed in the hope that it will be useful, |
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* but WITHOUT ANY WARRANTY; without even the implied warranty of |
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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* GNU General Public License for more details. |
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* |
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* You should have received a copy of the GNU General Public License |
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* along with this program; if not, write to the Free Software |
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
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* |
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* Under section 8 of the GNU General Public License, the copyright |
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* holders of XVID explicitly forbid distribution in the following |
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* countries: |
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* |
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* - Japan |
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* - United States of America |
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* |
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* Linking XviD statically or dynamically with other modules is making a |
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* combined work based on XviD. Thus, the terms and conditions of the |
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* GNU General Public License cover the whole combination. |
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* |
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* As a special exception, the copyright holders of XviD give you |
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* permission to link XviD with independent modules that communicate with |
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* XviD solely through the VFW1.1 and DShow interfaces, regardless of the |
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* license terms of these independent modules, and to copy and distribute |
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* the resulting combined work under terms of your choice, provided that |
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* every copy of the combined work is accompanied by a complete copy of |
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* the source code of XviD (the version of XviD used to produce the |
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* combined work), being distributed under the terms of the GNU General |
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* Public License plus this exception. An independent module is a module |
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* which is not derived from or based on XviD. |
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* |
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* Note that people who make modified versions of XviD are not obligated |
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* to grant this special exception for their modified versions; it is |
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* their choice whether to do so. The GNU General Public License gives |
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* permission to release a modified version without this exception; this |
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* exception also makes it possible to release a modified version which |
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* carries forward this exception. |
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* |
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* $Id: idct.c,v 1.4 2002-11-16 23:51:58 edgomez Exp $ |
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* |
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*************************************************************************/ |
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/**********************************************************/ |
/**********************************************************/ |
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/* inverse two dimensional DCT, Chen-Wang algorithm */ |
/* inverse two dimensional DCT, Chen-Wang algorithm */ |
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/* this code assumes >> to be a two's-complement arithmetic */ |
/* this code assumes >> to be a two's-complement arithmetic */ |
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/* right shift: (-2)>>1 == -1 , (-3)>>1 == -2 */ |
/* right shift: (-2)>>1 == -1 , (-3)>>1 == -2 */ |
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//#include <windows.h> |
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#include "idct.h" |
#include "idct.h" |
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#define W1 2841 /* 2048*sqrt(2)*cos(1*pi/16) */ |
#define W1 2841 /* 2048*sqrt(2)*cos(1*pi/16) */ |
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/* two dimensional inverse discrete cosine transform */ |
/* two dimensional inverse discrete cosine transform */ |
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//void j_rev_dct(block) |
//void j_rev_dct(block) |
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//short *block; |
//short *block; |
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void idct_int32(short * const block) |
void |
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idct_int32(short *const block) |
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{ |
{ |
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// idct_int32_init() must be called before the first call to this function! |
// idct_int32_init() must be called before the first call to this function! |
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for (i=0; i<8; i++) // idct rows |
for (i=0; i<8; i++) // idct rows |
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{ |
{ |
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blk = block+(i<<3); |
blk = block+(i<<3); |
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if (!((X1 = blk[4]<<11) | (X2 = blk[6]) | (X3 = blk[2]) | |
if (! |
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(X4 = blk[1]) | (X5 = blk[7]) | (X6 = blk[5]) | (X7 = blk[3]))) |
((X1 = blk[4] << 11) | (X2 = blk[6]) | (X3 = blk[2]) | (X4 = |
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{ |
blk[1]) | |
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blk[0]=blk[1]=blk[2]=blk[3]=blk[4]=blk[5]=blk[6]=blk[7]=blk[0]<<3; |
(X5 = blk[7]) | (X6 = blk[5]) | (X7 = blk[3]))) { |
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blk[0] = blk[1] = blk[2] = blk[3] = blk[4] = blk[5] = blk[6] = |
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blk[7] = blk[0] << 3; |
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continue; |
continue; |
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} |
} |
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{ |
{ |
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blk = block + i; |
blk = block + i; |
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// shortcut |
// shortcut |
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if (!((X1 = (blk[8*4]<<8)) | (X2 = blk[8*6]) | (X3 = blk[8*2]) | |
if (! |
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(X4 = blk[8*1]) | (X5 = blk[8*7]) | (X6 = blk[8*5]) | (X7 = blk[8*3]))) |
((X1 = (blk[8 * 4] << 8)) | (X2 = blk[8 * 6]) | (X3 = |
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{ |
blk[8 * |
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2]) | (X4 = |
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blk[8 * |
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1]) |
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| (X5 = blk[8 * 7]) | (X6 = blk[8 * 5]) | (X7 = blk[8 * 3]))) { |
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blk[8*0]=blk[8*1]=blk[8*2]=blk[8*3]=blk[8*4]= |
blk[8*0]=blk[8*1]=blk[8*2]=blk[8*3]=blk[8*4]= |
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blk[8*5]=blk[8*6]=blk[8*7]=iclp[(blk[8*0]+32)>>6]; |
blk[8 * 5] = blk[8 * 6] = blk[8 * 7] = |
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iclp[(blk[8 * 0] + 32) >> 6]; |
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continue; |
continue; |
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} |
} |
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//void |
//void |
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//idct_int32_init() |
//idct_int32_init() |
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void idct_int32_init() |
void |
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idct_int32_init() |
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{ |
{ |
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int i; |
int i; |
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