/***************************************************************************** * * 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 1.5 2008/11/26 02:21:02 Isibaar 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 ****************************************************************************/ /* divide-by-multiply table * needs 17 bit shift (16 causes slight errors when q > 19) */ #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 */ 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 uint16_t * intra_matrix_rec = mpeg_quant_matrices + 1*64; int i; int rounding = 1<<(SCALEBITS-1-3); coeff[0] = DIV_DIV(data[0], (int32_t) dcscalar); for (i = 1; i < 64; i++) { int32_t level = data[i]; level *= intra_matrix_rec[i]; level = (level + rounding)>>(SCALEBITS-3); coeff[i] = level; } 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); }