1/* 2 * gain code, gain pitch and pitch delay decoding 3 * 4 * Copyright (c) 2008 Vladimir Voroshilov 5 * 6 * This file is part of Libav. 7 * 8 * Libav 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 * Libav 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 Libav; 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/mathematics.h" 24#include "avcodec.h" 25#include "dsputil.h" 26#include "acelp_pitch_delay.h" 27#include "celp_math.h" 28 29int ff_acelp_decode_8bit_to_1st_delay3(int ac_index) 30{ 31 ac_index += 58; 32 if(ac_index > 254) 33 ac_index = 3 * ac_index - 510; 34 return ac_index; 35} 36 37int ff_acelp_decode_4bit_to_2nd_delay3( 38 int ac_index, 39 int pitch_delay_min) 40{ 41 if(ac_index < 4) 42 return 3 * (ac_index + pitch_delay_min); 43 else if(ac_index < 12) 44 return 3 * pitch_delay_min + ac_index + 6; 45 else 46 return 3 * (ac_index + pitch_delay_min) - 18; 47} 48 49int ff_acelp_decode_5_6_bit_to_2nd_delay3( 50 int ac_index, 51 int pitch_delay_min) 52{ 53 return 3 * pitch_delay_min + ac_index - 2; 54} 55 56int ff_acelp_decode_9bit_to_1st_delay6(int ac_index) 57{ 58 if(ac_index < 463) 59 return ac_index + 105; 60 else 61 return 6 * (ac_index - 368); 62} 63int ff_acelp_decode_6bit_to_2nd_delay6( 64 int ac_index, 65 int pitch_delay_min) 66{ 67 return 6 * pitch_delay_min + ac_index - 3; 68} 69 70void ff_acelp_update_past_gain( 71 int16_t* quant_energy, 72 int gain_corr_factor, 73 int log2_ma_pred_order, 74 int erasure) 75{ 76 int i; 77 int avg_gain=quant_energy[(1 << log2_ma_pred_order) - 1]; // (5.10) 78 79 for(i=(1 << log2_ma_pred_order) - 1; i>0; i--) 80 { 81 avg_gain += quant_energy[i-1]; 82 quant_energy[i] = quant_energy[i-1]; 83 } 84 85 if(erasure) 86 quant_energy[0] = FFMAX(avg_gain >> log2_ma_pred_order, -10240) - 4096; // -10 and -4 in (5.10) 87 else 88 quant_energy[0] = (6165 * ((ff_log2(gain_corr_factor) >> 2) - (13 << 13))) >> 13; 89} 90 91int16_t ff_acelp_decode_gain_code( 92 DSPContext *dsp, 93 int gain_corr_factor, 94 const int16_t* fc_v, 95 int mr_energy, 96 const int16_t* quant_energy, 97 const int16_t* ma_prediction_coeff, 98 int subframe_size, 99 int ma_pred_order) 100{ 101 int i; 102 103 mr_energy <<= 10; 104 105 for(i=0; i<ma_pred_order; i++) 106 mr_energy += quant_energy[i] * ma_prediction_coeff[i]; 107 108 mr_energy = gain_corr_factor * exp(M_LN10 / (20 << 23) * mr_energy) / 109 sqrt(dsp->scalarproduct_int16(fc_v, fc_v, subframe_size, 0)); 110 return mr_energy >> 12; 111} 112 113float ff_amr_set_fixed_gain(float fixed_gain_factor, float fixed_mean_energy, 114 float *prediction_error, float energy_mean, 115 const float *pred_table) 116{ 117 // Equations 66-69: 118 // ^g_c = ^gamma_gc * 100.05 (predicted dB + mean dB - dB of fixed vector) 119 // Note 10^(0.05 * -10log(average x2)) = 1/sqrt((average x2)). 120 float val = fixed_gain_factor * 121 exp2f(M_LOG2_10 * 0.05 * 122 (ff_dot_productf(pred_table, prediction_error, 4) + 123 energy_mean)) / 124 sqrtf(fixed_mean_energy); 125 126 // update quantified prediction error energy history 127 memmove(&prediction_error[0], &prediction_error[1], 128 3 * sizeof(prediction_error[0])); 129 prediction_error[3] = 20.0 * log10f(fixed_gain_factor); 130 131 return val; 132} 133 134void ff_decode_pitch_lag(int *lag_int, int *lag_frac, int pitch_index, 135 const int prev_lag_int, const int subframe, 136 int third_as_first, int resolution) 137{ 138 /* Note n * 10923 >> 15 is floor(x/3) for 0 <= n <= 32767 */ 139 if (subframe == 0 || (subframe == 2 && third_as_first)) { 140 141 if (pitch_index < 197) 142 pitch_index += 59; 143 else 144 pitch_index = 3 * pitch_index - 335; 145 146 } else { 147 if (resolution == 4) { 148 int search_range_min = av_clip(prev_lag_int - 5, PITCH_DELAY_MIN, 149 PITCH_DELAY_MAX - 9); 150 151 // decoding with 4-bit resolution 152 if (pitch_index < 4) { 153 // integer only precision for [search_range_min, search_range_min+3] 154 pitch_index = 3 * (pitch_index + search_range_min) + 1; 155 } else if (pitch_index < 12) { 156 // 1/3 fractional precision for [search_range_min+3 1/3, search_range_min+5 2/3] 157 pitch_index += 3 * search_range_min + 7; 158 } else { 159 // integer only precision for [search_range_min+6, search_range_min+9] 160 pitch_index = 3 * (pitch_index + search_range_min - 6) + 1; 161 } 162 } else { 163 // decoding with 5 or 6 bit resolution, 1/3 fractional precision 164 pitch_index--; 165 166 if (resolution == 5) { 167 pitch_index += 3 * av_clip(prev_lag_int - 10, PITCH_DELAY_MIN, 168 PITCH_DELAY_MAX - 19); 169 } else 170 pitch_index += 3 * av_clip(prev_lag_int - 5, PITCH_DELAY_MIN, 171 PITCH_DELAY_MAX - 9); 172 } 173 } 174 *lag_int = pitch_index * 10923 >> 15; 175 *lag_frac = pitch_index - 3 * *lag_int - 1; 176} 177