/***************************************************************************** * *  XVID MPEG-4 VIDEO CODEC *  - MPEG4 Quantization H263 implementation - * *  Copyright(C) 2001-2003 Peter Ross <pross@xvid.org> * *  This program is free software ; you can redistribute it and/or modify *  it under the terms of the GNU General Public License as published by *  the Free Software Foundation ; either version 2 of the License, or *  (at your option) any later version. * *  This program is distributed in the hope that it will be useful, *  but WITHOUT ANY WARRANTY ; without even the implied warranty of *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the *  GNU General Public License for more details. * *  You should have received a copy of the GNU General Public License *  along with this program ; if not, write to the Free Software *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA * * $Id$ * ****************************************************************************/#include "../global.h"#include "quant.h"/***************************************************************************** * Global function pointers ****************************************************************************//* Quant */quant_intraFuncPtr quant_h263_intra;quant_interFuncPtr quant_h263_inter;/* DeQuant */quant_intraFuncPtr dequant_h263_intra;quant_interFuncPtr dequant_h263_inter;/***************************************************************************** * Local data ****************************************************************************//* divide-by-multiply table * a 16 bit shiting is enough in this case */#define SCALEBITS	16#define FIX(X)		((1L << SCALEBITS) / (X) + 1)static const uint32_t multipliers[32] ={	0,       FIX(2),  FIX(4),  FIX(6),	FIX(8),  FIX(10), FIX(12), FIX(14),	FIX(16), FIX(18), FIX(20), FIX(22),	FIX(24), FIX(26), FIX(28), FIX(30),	FIX(32), FIX(34), FIX(36), FIX(38),	FIX(40), FIX(42), FIX(44), FIX(46),	FIX(48), FIX(50), FIX(52), FIX(54),	FIX(56), FIX(58), FIX(60), FIX(62)};/***************************************************************************** * Function definitions ****************************************************************************//*	quantize intra-block */uint32_tquant_h263_intra_c(int16_t * coeff,				   const int16_t * data,				   const uint32_t quant,				   const uint32_t dcscalar,				   const uint16_t * mpeg_quant_matrices){	const uint32_t mult = multipliers[quant];	const uint16_t quant_m_2 = quant << 1;	int i;	coeff[0] = DIV_DIV(data[0], (int32_t) dcscalar);	for (i = 1; i < 64; i++) {		int16_t acLevel = data[i];		if (acLevel < 0) {			acLevel = -acLevel;			if (acLevel < quant_m_2) {				coeff[i] = 0;				continue;			}			acLevel = (acLevel * mult) >> SCALEBITS;			coeff[i] = -acLevel;		} else {			if (acLevel < quant_m_2) {				coeff[i] = 0;				continue;			}			acLevel = (acLevel * mult) >> SCALEBITS;			coeff[i] = acLevel;		}	}	return(0);}/*	quantize inter-block */uint32_tquant_h263_inter_c(int16_t * coeff,				   const int16_t * data,				   const uint32_t quant,				   const uint16_t * mpeg_quant_matrices){	const uint32_t mult = multipliers[quant];	const uint16_t quant_m_2 = quant << 1;	const uint16_t quant_d_2 = quant >> 1;	uint32_t sum = 0;	uint32_t i;	for (i = 0; i < 64; i++) {		int16_t acLevel = data[i];		if (acLevel < 0) {			acLevel = (-acLevel) - quant_d_2;			if (acLevel < quant_m_2) {				coeff[i] = 0;				continue;			}			acLevel = (acLevel * mult) >> SCALEBITS;			sum += acLevel;		/* sum += |acLevel| */			coeff[i] = -acLevel;		} else {			acLevel -= quant_d_2;			if (acLevel < quant_m_2) {				coeff[i] = 0;				continue;			}			acLevel = (acLevel * mult) >> SCALEBITS;			sum += acLevel;			coeff[i] = acLevel;		}	}	return(sum);}/*	dequantize intra-block & clamp to [-2048,2047] */uint32_tdequant_h263_intra_c(int16_t * data,					 const int16_t * coeff,					 const uint32_t quant,					 const uint32_t dcscalar,					 const uint16_t * mpeg_quant_matrices){	const int32_t quant_m_2 = quant << 1;	const int32_t quant_add = (quant & 1 ? quant : quant - 1);	int i;	data[0] = coeff[0] * dcscalar;	if (data[0] < -2048) {		data[0] = -2048;	} else if (data[0] > 2047) {		data[0] = 2047;	}	for (i = 1; i < 64; i++) {		int32_t acLevel = coeff[i];		if (acLevel == 0) {			data[i] = 0;		} else if (acLevel < 0) {			acLevel = quant_m_2 * -acLevel + quant_add;			data[i] = (acLevel <= 2048 ? -acLevel : -2048);		} else {			acLevel = quant_m_2 * acLevel + quant_add;			data[i] = (acLevel <= 2047 ? acLevel : 2047);		}	}	return(0);}/* dequantize inter-block & clamp to [-2048,2047] */uint32_tdequant_h263_inter_c(int16_t * data,					 const int16_t * coeff,					 const uint32_t quant,					 const uint16_t * mpeg_quant_matrices){	const uint16_t quant_m_2 = quant << 1;	const uint16_t quant_add = (quant & 1 ? quant : quant - 1);	int i;	for (i = 0; i < 64; i++) {		int16_t acLevel = coeff[i];		if (acLevel == 0) {			data[i] = 0;		} else if (acLevel < 0) {			acLevel = acLevel * quant_m_2 - quant_add;			data[i] = (acLevel >= -2048 ? acLevel : -2048);		} else {			acLevel = acLevel * quant_m_2 + quant_add;			data[i] = (acLevel <= 2047 ? acLevel : 2047);		}	}	return(0);}