--- quant_mpeg4.c 2003/01/04 06:14:33 1.3.2.1 +++ quant_mpeg4.c 2002/11/26 23:44:11 1.7 @@ -1,62 +1,86 @@ -/************************************************************************** +/***************************************************************************** * - * XVID MPEG-4 VIDEO CODEC - * mpeg-4 quantization/dequantization + * XVID MPEG-4 VIDEO CODEC + * - Mpeg4 quantization/dequantization functions - * - * 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. + * Copyright(C) 2002 Peter Ross * - * 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 file is part of XviD, a free MPEG-4 video encoder/decoder * - * 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. + * 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. * - * 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. + * 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 + * + * 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 * - * History: + * 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. * - * 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 + * 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. + * + * $Id: quant_mpeg4.c,v 1.7 2002/11/26 23:44:11 edgomez Exp $ + * + ****************************************************************************/ -#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) @@ -72,13 +96,18 @@ FIX(56), FIX(58), FIX(60), FIX(62) }; -/* quantize intra-block +/***************************************************************************** + * Functions + ****************************************************************************/ + +#if 0 +/* 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, @@ -116,9 +145,9 @@ -/* 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, @@ -146,7 +175,7 @@ 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]; @@ -158,12 +187,13 @@ -/* quantize inter-block +#if 0 +/* 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, @@ -224,7 +254,7 @@ 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]; @@ -235,7 +265,7 @@ sum ^= data[i]; } - // mismatch control + /* mismatch control */ if ((sum & 1) == 0) { data[63] ^= 1;