--- quant_mpeg.c 2003/10/07 13:02:35 1.1 +++ quant_mpeg.c 2004/03/22 22:36:24 1.2 @@ -0,0 +1,234 @@ +/***************************************************************************** + * + * XVID MPEG-4 VIDEO CODEC + * - MPEG4 Quantization related header - + * + * Copyright(C) 2001-2003 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 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: quant_mpeg.c,v 1.2 2004/03/22 22:36:24 edgomez Exp $ + * + ****************************************************************************/ + +#include "../global.h" +#include "quant.h" +#include "quant_matrix.h" + +/***************************************************************************** + * Global function pointers + ****************************************************************************/ + +/* Quant */ +quant_intraFuncPtr quant_mpeg_intra; +quant_interFuncPtr quant_mpeg_inter; + +/* DeQuant */ +quant_intraFuncPtr dequant_mpeg_intra; +quant_interFuncPtr dequant_mpeg_inter; + +/***************************************************************************** + * Local data + ****************************************************************************/ + +#define VM18P 3 +#define VM18Q 4 + +/* divide-by-multiply table + * needs 17 bit shift (16 causes slight errors when q > 19) */ + +#define SCALEBITS 17 +#define FIX(X) ((1UL << 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 + * + * const int32_t quantd = DIV_DIV(VM18P*quant, VM18Q); + * level = DIV_DIV(16 * data[i], default_intra_matrix[i]); + * coeff[i] = (level + quantd) / quant2; + */ + +uint32_t +quant_mpeg_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 quantd = ((VM18P * quant) + (VM18Q / 2)) / VM18Q; + const uint32_t mult = multipliers[quant]; + const uint16_t *intra_matrix = get_intra_matrix(mpeg_quant_matrices); + int i; + + coeff[0] = DIV_DIV(data[0], (int32_t) dcscalar); + + for (i = 1; i < 64; i++) { + if (data[i] < 0) { + uint32_t level = -data[i]; + + level = ((level << 4) + (intra_matrix[i] >> 1)) / intra_matrix[i]; + level = ((level + quantd) * mult) >> SCALEBITS; + coeff[i] = -(int16_t) level; + } else if (data[i] > 0) { + uint32_t level = data[i]; + + level = ((level << 4) + (intra_matrix[i] >> 1)) / intra_matrix[i]; + level = ((level + quantd) * mult) >> SCALEBITS; + coeff[i] = level; + } else { + coeff[i] = 0; + } + } + + return(0); +} + +/* quantize inter-block + * + * level = DIV_DIV(16 * data[i], default_intra_matrix[i]); + * coeff[i] = (level + quantd) / quant2; + * sum += abs(level); + */ + +uint32_t +quant_mpeg_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 *inter_matrix = get_inter_matrix(mpeg_quant_matrices); + uint32_t sum = 0; + int i; + + for (i = 0; i < 64; i++) { + if (data[i] < 0) { + uint32_t level = -data[i]; + + level = ((level << 4) + (inter_matrix[i] >> 1)) / inter_matrix[i]; + level = (level * mult) >> 17; + sum += level; + coeff[i] = -(int16_t) level; + } else if (data[i] > 0) { + uint32_t level = data[i]; + + level = ((level << 4) + (inter_matrix[i] >> 1)) / inter_matrix[i]; + level = (level * mult) >> 17; + sum += level; + coeff[i] = level; + } else { + coeff[i] = 0; + } + } + + return(sum); +} + +/* dequantize intra-block & clamp to [-2048,2047] + * + * data[i] = (coeff[i] * default_intra_matrix[i] * quant2) >> 4; + */ + +uint32_t +dequant_mpeg_intra_c(int16_t * data, + const int16_t * coeff, + const uint32_t quant, + const uint32_t dcscalar, + const uint16_t * mpeg_quant_matrices) +{ + const uint16_t *intra_matrix = get_intra_matrix(mpeg_quant_matrices); + 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++) { + if (coeff[i] == 0) { + data[i] = 0; + } else if (coeff[i] < 0) { + uint32_t level = -coeff[i]; + + level = (level * intra_matrix[i] * quant) >> 3; + data[i] = (level <= 2048 ? -(int16_t) level : -2048); + } else { + uint32_t level = coeff[i]; + + level = (level * intra_matrix[i] * quant) >> 3; + data[i] = (level <= 2047 ? level : 2047); + } + } + + return(0); +} + + +/* dequantize inter-block & clamp to [-2048,2047] + * data = ((2 * coeff + SIGN(coeff)) * inter_matrix[i] * quant) / 16 + */ + +uint32_t +dequant_mpeg_inter_c(int16_t * data, + const int16_t * coeff, + const uint32_t quant, + const uint16_t * mpeg_quant_matrices) +{ + uint32_t sum = 0; + const uint16_t *inter_matrix = get_inter_matrix(mpeg_quant_matrices); + int i; + + for (i = 0; i < 64; i++) { + if (coeff[i] == 0) { + data[i] = 0; + } else if (coeff[i] < 0) { + int32_t level = -coeff[i]; + + level = ((2 * level + 1) * inter_matrix[i] * quant) >> 4; + data[i] = (level <= 2048 ? -level : -2048); + } else { + uint32_t level = coeff[i]; + + level = ((2 * level + 1) * inter_matrix[i] * quant) >> 4; + data[i] = (level <= 2047 ? level : 2047); + } + + sum ^= data[i]; + } + + /* mismatch control */ + if ((sum & 1) == 0) { + data[63] ^= 1; + } + + return(0); +}