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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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* mpeg-4 quantization/dequantization |
* - Mpeg4 quantization/dequantization functions - |
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* |
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* Copyright(C) 2002 Peter Ross |
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* |
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* This program is an implementation of a part of one or more MPEG-4 |
* This program is an implementation of a part of one or more MPEG-4 |
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* Video tools as specified in ISO/IEC 14496-2 standard. Those intending |
* Video tools as specified in ISO/IEC 14496-2 standard. Those intending |
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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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/************************************************************************** |
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* History: |
* $Id$ |
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* |
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* 26.01.2002 fixed quant4_intra dcscalar signed/unsigned error |
****************************************************************************/ |
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* 20.01.2002 increased accuracy of >> divide |
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* 26.12.2001 divide-by-multiplication optimization |
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* 22.12.2001 [-127,127] clamping removed; minor tweaks |
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* 19.11.2001 inital version <pross@cs.rmit.edu.au> |
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* |
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*************************************************************************/ |
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#include "quant_mpeg4.h" |
#include "quant_mpeg4.h" |
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#include "quant_matrix.h" |
#include "quant_matrix.h" |
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// function pointers |
/***************************************************************************** |
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* Function pointers |
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****************************************************************************/ |
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quant_intraFuncPtr quant4_intra; |
quant_intraFuncPtr quant4_intra; |
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quant_intraFuncPtr dequant4_intra; |
quant_intraFuncPtr dequant4_intra; |
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dequant_interFuncPtr dequant4_inter; |
dequant_interFuncPtr dequant4_inter; |
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quant_interFuncPtr quant4_inter; |
quant_interFuncPtr quant4_inter; |
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/***************************************************************************** |
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* Local data |
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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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#define SIGN(A) ((A)>0?1:-1) |
#define SIGN(A) ((A)>0?1:-1) |
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#define VM18P 3 |
#define VM18P 3 |
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#define VM18Q 4 |
#define VM18Q 4 |
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// divide-by-multiply table |
/* |
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// need 17 bit shift (16 causes slight errors when q > 19) |
* divide-by-multiply table |
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* need 17 bit shift (16 causes slight errors when q > 19) |
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*/ |
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#define SCALEBITS 17 |
#define SCALEBITS 17 |
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#define FIX(X) ((1UL << SCALEBITS) / (X) + 1) |
#define FIX(X) ((1UL << SCALEBITS) / (X) + 1) |
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FIX(56), FIX(58), FIX(60), FIX(62) |
FIX(56), FIX(58), FIX(60), FIX(62) |
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}; |
}; |
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/***************************************************************************** |
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* Functions |
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****************************************************************************/ |
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/* quantize intra-block |
/* quantize intra-block |
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// const int32_t quantd = DIV_DIV(VM18P*quant, VM18Q); |
// const int32_t quantd = DIV_DIV(VM18P*quant, VM18Q); |