1/* 2 * gain code, gain pitch and pitch delay decoding 3 * 4 * Copyright (c) 2008 Vladimir Voroshilov 5 * 6 * This file is part of FFmpeg. 7 * 8 * FFmpeg is free software; you can redistribute it and/or 9 * modify it under the terms of the GNU Lesser General Public 10 * License as published by the Free Software Foundation; either 11 * version 2.1 of the License, or (at your option) any later version. 12 * 13 * FFmpeg is distributed in the hope that it will be useful, 14 * but WITHOUT ANY WARRANTY; without even the implied warranty of 15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 16 * Lesser General Public License for more details. 17 * 18 * You should have received a copy of the GNU Lesser General Public 19 * License along with FFmpeg; if not, write to the Free Software 20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 21 */ 22 23#include "libavutil/common.h" 24#include "libavutil/float_dsp.h" 25#include "libavutil/libm.h" 26#include "libavutil/mathematics.h" 27#include "avcodec.h" 28#include "acelp_pitch_delay.h" 29#include "celp_math.h" 30#include "audiodsp.h" 31 32int ff_acelp_decode_8bit_to_1st_delay3(int ac_index) 33{ 34 ac_index += 58; 35 if(ac_index > 254) 36 ac_index = 3 * ac_index - 510; 37 return ac_index; 38} 39 40int ff_acelp_decode_4bit_to_2nd_delay3( 41 int ac_index, 42 int pitch_delay_min) 43{ 44 if(ac_index < 4) 45 return 3 * (ac_index + pitch_delay_min); 46 else if(ac_index < 12) 47 return 3 * pitch_delay_min + ac_index + 6; 48 else 49 return 3 * (ac_index + pitch_delay_min) - 18; 50} 51 52int ff_acelp_decode_5_6_bit_to_2nd_delay3( 53 int ac_index, 54 int pitch_delay_min) 55{ 56 return 3 * pitch_delay_min + ac_index - 2; 57} 58 59int ff_acelp_decode_9bit_to_1st_delay6(int ac_index) 60{ 61 if(ac_index < 463) 62 return ac_index + 105; 63 else 64 return 6 * (ac_index - 368); 65} 66int ff_acelp_decode_6bit_to_2nd_delay6( 67 int ac_index, 68 int pitch_delay_min) 69{ 70 return 6 * pitch_delay_min + ac_index - 3; 71} 72 73void ff_acelp_update_past_gain( 74 int16_t* quant_energy, 75 int gain_corr_factor, 76 int log2_ma_pred_order, 77 int erasure) 78{ 79 int i; 80 int avg_gain=quant_energy[(1 << log2_ma_pred_order) - 1]; // (5.10) 81 82 for(i=(1 << log2_ma_pred_order) - 1; i>0; i--) 83 { 84 avg_gain += quant_energy[i-1]; 85 quant_energy[i] = quant_energy[i-1]; 86 } 87 88 if(erasure) 89 quant_energy[0] = FFMAX(avg_gain >> log2_ma_pred_order, -10240) - 4096; // -10 and -4 in (5.10) 90 else 91 quant_energy[0] = (6165 * ((ff_log2_q15(gain_corr_factor) >> 2) - (13 << 13))) >> 13; 92} 93 94int16_t ff_acelp_decode_gain_code( 95 AudioDSPContext *adsp, 96 int gain_corr_factor, 97 const int16_t* fc_v, 98 int mr_energy, 99 const int16_t* quant_energy, 100 const int16_t* ma_prediction_coeff, 101 int subframe_size, 102 int ma_pred_order) 103{ 104 int i; 105 106 mr_energy <<= 10; 107 108 for(i=0; i<ma_pred_order; i++) 109 mr_energy += quant_energy[i] * ma_prediction_coeff[i]; 110 111#ifdef G729_BITEXACT 112 mr_energy += (((-6165LL * ff_log2(dsp->scalarproduct_int16(fc_v, fc_v, subframe_size, 0))) >> 3) & ~0x3ff); 113 114 mr_energy = (5439 * (mr_energy >> 15)) >> 8; // (0.15) = (0.15) * (7.23) 115 116 return bidir_sal( 117 ((ff_exp2(mr_energy & 0x7fff) + 16) >> 5) * (gain_corr_factor >> 1), 118 (mr_energy >> 15) - 25 119 ); 120#else 121 mr_energy = gain_corr_factor * exp(M_LN10 / (20 << 23) * mr_energy) / 122 sqrt(adsp->scalarproduct_int16(fc_v, fc_v, subframe_size)); 123 return mr_energy >> 12; 124#endif 125} 126 127float ff_amr_set_fixed_gain(float fixed_gain_factor, float fixed_mean_energy, 128 float *prediction_error, float energy_mean, 129 const float *pred_table) 130{ 131 // Equations 66-69: 132 // ^g_c = ^gamma_gc * 100.05 (predicted dB + mean dB - dB of fixed vector) 133 // Note 10^(0.05 * -10log(average x2)) = 1/sqrt((average x2)). 134 float val = fixed_gain_factor * 135 exp2f(M_LOG2_10 * 0.05 * 136 (avpriv_scalarproduct_float_c(pred_table, prediction_error, 4) + 137 energy_mean)) / 138 sqrtf(fixed_mean_energy); 139 140 // update quantified prediction error energy history 141 memmove(&prediction_error[0], &prediction_error[1], 142 3 * sizeof(prediction_error[0])); 143 prediction_error[3] = 20.0 * log10f(fixed_gain_factor); 144 145 return val; 146} 147 148void ff_decode_pitch_lag(int *lag_int, int *lag_frac, int pitch_index, 149 const int prev_lag_int, const int subframe, 150 int third_as_first, int resolution) 151{ 152 /* Note n * 10923 >> 15 is floor(x/3) for 0 <= n <= 32767 */ 153 if (subframe == 0 || (subframe == 2 && third_as_first)) { 154 155 if (pitch_index < 197) 156 pitch_index += 59; 157 else 158 pitch_index = 3 * pitch_index - 335; 159 160 } else { 161 if (resolution == 4) { 162 int search_range_min = av_clip(prev_lag_int - 5, PITCH_DELAY_MIN, 163 PITCH_DELAY_MAX - 9); 164 165 // decoding with 4-bit resolution 166 if (pitch_index < 4) { 167 // integer only precision for [search_range_min, search_range_min+3] 168 pitch_index = 3 * (pitch_index + search_range_min) + 1; 169 } else if (pitch_index < 12) { 170 // 1/3 fractional precision for [search_range_min+3 1/3, search_range_min+5 2/3] 171 pitch_index += 3 * search_range_min + 7; 172 } else { 173 // integer only precision for [search_range_min+6, search_range_min+9] 174 pitch_index = 3 * (pitch_index + search_range_min - 6) + 1; 175 } 176 } else { 177 // decoding with 5 or 6 bit resolution, 1/3 fractional precision 178 pitch_index--; 179 180 if (resolution == 5) { 181 pitch_index += 3 * av_clip(prev_lag_int - 10, PITCH_DELAY_MIN, 182 PITCH_DELAY_MAX - 19); 183 } else 184 pitch_index += 3 * av_clip(prev_lag_int - 5, PITCH_DELAY_MIN, 185 PITCH_DELAY_MAX - 9); 186 } 187 } 188 *lag_int = pitch_index * 10923 >> 15; 189 *lag_frac = pitch_index - 3 * *lag_int - 1; 190} 191