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/***************************************************************************** |
/* idct.c, inverse fast discrete cosine transform */ |
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* |
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* XVID MPEG-4 VIDEO CODEC |
/* Copyright (C) 1996, MPEG Software Simulation Group. All Rights Reserved. */ |
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* - inverse fast disrete cosine transformation - integer C version |
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* |
/* |
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* These routines are from Independent JPEG Group's free JPEG software |
* Disclaimer of Warranty |
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* 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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* $Id$ |
* These software programs are available to the user without any license fee or |
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* royalty on an "as is" basis. The MPEG Software Simulation Group disclaims |
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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 |
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* platform ( in VC++ "int" -> 32bits ) |
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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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#define W6 1108 /* 2048*sqrt(2)*cos(6*pi/16) */ |
#define W6 1108 /* 2048*sqrt(2)*cos(6*pi/16) */ |
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#define W7 565 /* 2048*sqrt(2)*cos(7*pi/16) */ |
#define W7 565 /* 2048*sqrt(2)*cos(7*pi/16) */ |
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/* global declarations */ |
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/*void init_idct_int32 (void); */ |
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/*void idct_int32 (short *block); */ |
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/* private data */ |
/* private data */ |
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static short iclip[1024]; /* clipping table */ |
static short iclip[1024]; /* clipping table */ |
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static short *iclp; |
static short *iclp; |
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/* private prototypes */ |
/* private prototypes */ |
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/*static void idctrow _ANSI_ARGS_((short *blk)); */ |
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/*static void idctcol _ANSI_ARGS_((short *blk)); */ |
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/* row (horizontal) IDCT |
/* row (horizontal) IDCT |
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* |
* |
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* where: c[0] = 1/1024 |
* where: c[0] = 1/1024 |
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* c[1..7] = (1/1024)*sqrt(2) |
* c[1..7] = (1/1024)*sqrt(2) |
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*/ |
*/ |
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#if 0 |
#if 0 |
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static void idctcol(blk) |
static void idctcol(blk) |
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short *blk; |
short *blk; |
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idctFuncPtr idct; |
idctFuncPtr idct; |
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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) */ |
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/*short *block; */ |
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void |
void |
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idct_int32(short *const block) |
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! */ |
/* |
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* idct_int32_init() must be called before the first call to this |
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* function! |
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*/ |
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/*int i; |
#if 0 |
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int i; |
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long i; |
long i; |
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for (i=0; i<8; i++) |
for (i=0; i<8; i++) |
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idctrow(block+8*i); |
idctrow(block+8*i); |
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for (i=0; i<8; i++) |
for (i=0; i<8; i++) |
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idctcol(block+i); */ |
idctcol(block+i); |
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#endif |
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static short *blk; |
static short *blk; |
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static long i; |
static long i; |
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static long X0, X1, X2, X3, X4, X5, X6, X7, X8; |
static long X0, X1, X2, X3, X4, X5, X6, X7, X8; |
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} /* end function idct_int32(block) */ |
} /* end function idct_int32(block) */ |
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/*void */ |
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/*idct_int32_init() */ |
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void |
void |
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idct_int32_init(void) |
idct_int32_init() |
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{ |
{ |
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int i; |
int i; |
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