--- quant_mpeg4.c 2002/11/26 23:44:11 1.7 +++ quant_mpeg4.c 2003/02/15 15:22:19 1.9 @@ -1,86 +1,62 @@ -/***************************************************************************** +/************************************************************************** * - * XVID MPEG-4 VIDEO CODEC - * - Mpeg4 quantization/dequantization functions - + * XVID MPEG-4 VIDEO CODEC + * mpeg-4 quantization/dequantization * - * Copyright(C) 2002 Peter Ross + * This program is an implementation of a part of one or more MPEG-4 + * Video tools as specified in ISO/IEC 14496-2 standard. Those intending + * to use this software module in hardware or software products are + * advised that its use may infringe existing patents or copyrights, and + * any such use would be at such party's own risk. The original + * developer of this software module and his/her company, and subsequent + * editors and their companies, will have no liability for use of this + * software or modifications or derivatives thereof. * - * This file is part of XviD, a free MPEG-4 video encoder/decoder + * 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. * - * XviD 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. * - * 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., 675 Mass Ave, Cambridge, MA 02139, USA. * - * 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 - * - * Under section 8 of the GNU General Public License, the copyright - * holders of XVID explicitly forbid distribution in the following - * countries: - * - * - Japan - * - United States of America - * - * Linking XviD statically or dynamically with other modules is making a - * combined work based on XviD. Thus, the terms and conditions of the - * GNU General Public License cover the whole combination. - * - * As a special exception, the copyright holders of XviD give you - * permission to link XviD with independent modules that communicate with - * XviD solely through the VFW1.1 and DShow interfaces, regardless of the - * license terms of these independent modules, and to copy and distribute - * the resulting combined work under terms of your choice, provided that - * every copy of the combined work is accompanied by a complete copy of - * the source code of XviD (the version of XviD used to produce the - * combined work), being distributed under the terms of the GNU General - * Public License plus this exception. An independent module is a module - * which is not derived from or based on XviD. + *************************************************************************/ + +/************************************************************************** * - * Note that people who make modified versions of XviD are not obligated - * to grant this special exception for their modified versions; it is - * their choice whether to do so. The GNU General Public License gives - * permission to release a modified version without this exception; this - * exception also makes it possible to release a modified version which - * carries forward this exception. + * History: * - * $Id: quant_mpeg4.c,v 1.7 2002/11/26 23:44:11 edgomez Exp $ + * 26.01.2002 fixed quant4_intra dcscalar signed/unsigned error + * 20.01.2002 increased accuracy of >> divide + * 26.12.2001 divide-by-multiplication optimization + * 22.12.2001 [-127,127] clamping removed; minor tweaks + * 19.11.2001 inital version * - ****************************************************************************/ + *************************************************************************/ +#include "../global.h" #include "quant_mpeg4.h" #include "quant_matrix.h" -/***************************************************************************** - * Function pointers - ****************************************************************************/ - +// function pointers quant_intraFuncPtr quant4_intra; quant_intraFuncPtr dequant4_intra; dequant_interFuncPtr dequant4_inter; quant_interFuncPtr quant4_inter; -/***************************************************************************** - * Local data - ****************************************************************************/ - -#define DIV_DIV(A,B) ( (A) > 0 ? ((A)+((B)>>1))/(B) : ((A)-((B)>>1))/(B) ) -#define SIGN(A) ((A)>0?1:-1) #define VM18P 3 #define VM18Q 4 -/* - * divide-by-multiply table - * need 17 bit shift (16 causes slight errors when q > 19) - */ +// divide-by-multiply table +// need 17 bit shift (16 causes slight errors when q > 19) #define SCALEBITS 17 #define FIX(X) ((1UL << SCALEBITS) / (X) + 1) @@ -96,18 +72,13 @@ FIX(56), FIX(58), FIX(60), FIX(62) }; -/***************************************************************************** - * Functions - ****************************************************************************/ - -#if 0 -/* quantize intra-block */ +/* quantize intra-block // const int32_t quantd = DIV_DIV(VM18P*quant, VM18Q); // // level = DIV_DIV(16 * data[i], default_intra_matrix[i]); // coeff[i] = (level + quantd) / quant2; -#endif +*/ void quant4_intra_c(int16_t * coeff, @@ -145,9 +116,9 @@ -/* dequantize intra-block & clamp to [-2048,2047] */ - /* data[i] = (coeff[i] * default_intra_matrix[i] * quant2) >> 4; */ - +/* dequantize intra-block & clamp to [-2048,2047] + // data[i] = (coeff[i] * default_intra_matrix[i] * quant2) >> 4; +*/ void dequant4_intra_c(int16_t * data, @@ -175,7 +146,7 @@ level = (level * intra_matrix[i] * quant) >> 3; data[i] = (level <= 2048 ? -(int16_t) level : -2048); - } else /* if (coeff[i] > 0) */ + } else // if (coeff[i] > 0) { uint32_t level = coeff[i]; @@ -187,13 +158,12 @@ -#if 0 -/* quantize inter-block */ +/* quantize inter-block // level = DIV_DIV(16 * data[i], default_intra_matrix[i]); // coeff[i] = (level + quantd) / quant2; // sum += abs(level); -#endif +*/ uint32_t quant4_inter_c(int16_t * coeff, @@ -254,7 +224,7 @@ level = ((2 * level + 1) * inter_matrix[i] * quant) >> 4; data[i] = (level <= 2048 ? -level : -2048); - } else /* if (coeff[i] > 0) */ + } else // if (coeff[i] > 0) { uint32_t level = coeff[i]; @@ -265,7 +235,7 @@ sum ^= data[i]; } - /* mismatch control */ + // mismatch control if ((sum & 1) == 0) { data[63] ^= 1;