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/************************************************************************** |
/************************************************************************** |
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* |
* |
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* XVID MPEG-4 VIDEO CODEC |
* XVID MPEG-4 VIDEO CODEC |
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* quantization/dequantization |
* - quantization/dequantization - |
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* |
* |
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* This program is an implementation of a part of one or more MPEG-4 |
* This file is part of XviD, a free MPEG-4 video encoder/decoder |
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* Video tools as specified in ISO/IEC 14496-2 standard. Those intending |
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* to use this software module in hardware or software products are |
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* advised that its use may infringe existing patents or copyrights, and |
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* any such use would be at such party's own risk. The original |
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* developer of this software module and his/her company, and subsequent |
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* editors and their companies, will have no liability for use of this |
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* software or modifications or derivatives thereof. |
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* |
* |
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* This program is free software; you can redistribute it and/or modify |
* XviD is free software; you can redistribute it and/or modify it |
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* it under the terms of the GNU General Public License as published by |
* 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 |
* the Free Software Foundation; either version 2 of the License, or |
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* (at your option) any later version. |
* (at your option) any later version. |
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* |
* |
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* |
* |
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* You should have received a copy of the GNU General Public License |
* 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 |
* along with this program; if not, write to the Free Software |
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. |
* 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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* History: |
* - 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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* 26.12.2001 dequant_inter bug fix |
* $Id: quant_h263.c,v 1.5 2002-11-26 23:44:11 edgomez Exp $ |
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* 22.12.2001 clamp dequant output to [-2048,2047] |
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* 19.11.2001 quant_inter now returns sum of abs. coefficient values |
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* 02.11.2001 added const to function args <pross@cs.rmit.edu.au> |
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* 28.10.2001 total rewrite <pross@cs.rmit.edu.au> |
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* |
* |
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*************************************************************************/ |
*************************************************************************/ |
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#define DIV_DIV(a, b) ((a)>0) ? ((a)+((b)>>1))/(b) : ((a)-((b)>>1))/(b) |
#define DIV_DIV(a, b) ((a)>0) ? ((a)+((b)>>1))/(b) : ((a)-((b)>>1))/(b) |
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// function pointers |
/* function pointers */ |
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quanth263_intraFuncPtr quant_intra; |
quanth263_intraFuncPtr quant_intra; |
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quanth263_intraFuncPtr dequant_intra; |
quanth263_intraFuncPtr dequant_intra; |
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} |
} |
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acLevel = (acLevel * mult) >> SCALEBITS; |
acLevel = (acLevel * mult) >> SCALEBITS; |
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sum += acLevel; // sum += |acLevel| |
sum += acLevel; /* sum += |acLevel| */ |
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coeff[i] = -acLevel; |
coeff[i] = -acLevel; |
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} else { |
} else { |
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acLevel -= quant_d_2; |
acLevel -= quant_d_2; |
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} else if (acLevel < 0) { |
} else if (acLevel < 0) { |
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acLevel = quant_m_2 * -acLevel + quant_add; |
acLevel = quant_m_2 * -acLevel + quant_add; |
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data[i] = (acLevel <= 2048 ? -acLevel : -2048); |
data[i] = (acLevel <= 2048 ? -acLevel : -2048); |
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} else // if (acLevel > 0) { |
} else /* if (acLevel > 0) { */ |
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{ |
{ |
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acLevel = quant_m_2 * acLevel + quant_add; |
acLevel = quant_m_2 * acLevel + quant_add; |
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data[i] = (acLevel <= 2047 ? acLevel : 2047); |
data[i] = (acLevel <= 2047 ? acLevel : 2047); |
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} else if (acLevel < 0) { |
} else if (acLevel < 0) { |
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acLevel = acLevel * quant_m_2 - quant_add; |
acLevel = acLevel * quant_m_2 - quant_add; |
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data[i] = (acLevel >= -2048 ? acLevel : -2048); |
data[i] = (acLevel >= -2048 ? acLevel : -2048); |
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} else // if (acLevel > 0) |
} else /* if (acLevel > 0) */ |
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{ |
{ |
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acLevel = acLevel * quant_m_2 + quant_add; |
acLevel = acLevel * quant_m_2 + quant_add; |
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data[i] = (acLevel <= 2047 ? acLevel : 2047); |
data[i] = (acLevel <= 2047 ? acLevel : 2047); |