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 "avcodec.h" 24#include "dsputil.h" 25#include "acelp_pitch_delay.h" 26#include "celp_math.h" 27 28int ff_acelp_decode_8bit_to_1st_delay3(int ac_index) 29{ 30 ac_index += 58; 31 if(ac_index > 254) 32 ac_index = 3 * ac_index - 510; 33 return ac_index; 34} 35 36int ff_acelp_decode_4bit_to_2nd_delay3( 37 int ac_index, 38 int pitch_delay_min) 39{ 40 if(ac_index < 4) 41 return 3 * (ac_index + pitch_delay_min); 42 else if(ac_index < 12) 43 return 3 * pitch_delay_min + ac_index + 6; 44 else 45 return 3 * (ac_index + pitch_delay_min) - 18; 46} 47 48int ff_acelp_decode_5_6_bit_to_2nd_delay3( 49 int ac_index, 50 int pitch_delay_min) 51{ 52 return 3 * pitch_delay_min + ac_index - 2; 53} 54 55int ff_acelp_decode_9bit_to_1st_delay6(int ac_index) 56{ 57 if(ac_index < 463) 58 return ac_index + 105; 59 else 60 return 6 * (ac_index - 368); 61} 62int ff_acelp_decode_6bit_to_2nd_delay6( 63 int ac_index, 64 int pitch_delay_min) 65{ 66 return 6 * pitch_delay_min + ac_index - 3; 67} 68 69void ff_acelp_update_past_gain( 70 int16_t* quant_energy, 71 int gain_corr_factor, 72 int log2_ma_pred_order, 73 int erasure) 74{ 75 int i; 76 int avg_gain=quant_energy[(1 << log2_ma_pred_order) - 1]; // (5.10) 77 78 for(i=(1 << log2_ma_pred_order) - 1; i>0; i--) 79 { 80 avg_gain += quant_energy[i-1]; 81 quant_energy[i] = quant_energy[i-1]; 82 } 83 84 if(erasure) 85 quant_energy[0] = FFMAX(avg_gain >> log2_ma_pred_order, -10240) - 4096; // -10 and -4 in (5.10) 86 else 87 quant_energy[0] = (6165 * ((ff_log2(gain_corr_factor) >> 2) - (13 << 13))) >> 13; 88} 89 90int16_t ff_acelp_decode_gain_code( 91 DSPContext *dsp, 92 int gain_corr_factor, 93 const int16_t* fc_v, 94 int mr_energy, 95 const int16_t* quant_energy, 96 const int16_t* ma_prediction_coeff, 97 int subframe_size, 98 int ma_pred_order) 99{ 100 int i; 101 102 mr_energy <<= 10; 103 104 for(i=0; i<ma_pred_order; i++) 105 mr_energy += quant_energy[i] * ma_prediction_coeff[i]; 106 107#ifdef G729_BITEXACT 108 mr_energy += (((-6165LL * ff_log2(dsp->scalarproduct_int16(fc_v, fc_v, subframe_size, 0))) >> 3) & ~0x3ff); 109 110 mr_energy = (5439 * (mr_energy >> 15)) >> 8; // (0.15) = (0.15) * (7.23) 111 112 return bidir_sal( 113 ((ff_exp2(mr_energy & 0x7fff) + 16) >> 5) * (gain_corr_factor >> 1), 114 (mr_energy >> 15) - 25 115 ); 116#else 117 mr_energy = gain_corr_factor * exp(M_LN10 / (20 << 23) * mr_energy) / 118 sqrt(dsp->scalarproduct_int16(fc_v, fc_v, subframe_size, 0)); 119 return mr_energy >> 12; 120#endif 121} 122 123float ff_amr_set_fixed_gain(float fixed_gain_factor, float fixed_mean_energy, 124 float *prediction_error, float energy_mean, 125 const float *pred_table) 126{ 127 // Equations 66-69: 128 // ^g_c = ^gamma_gc * 100.05 (predicted dB + mean dB - dB of fixed vector) 129 // Note 10^(0.05 * -10log(average x2)) = 1/sqrt((average x2)). 130 float val = fixed_gain_factor * 131 exp2f(M_LOG2_10 * 0.05 * 132 (ff_dot_productf(pred_table, prediction_error, 4) + 133 energy_mean)) / 134 sqrtf(fixed_mean_energy); 135 136 // update quantified prediction error energy history 137 memmove(&prediction_error[0], &prediction_error[1], 138 3 * sizeof(prediction_error[0])); 139 prediction_error[3] = 20.0 * log10f(fixed_gain_factor); 140 141 return val; 142} 143 144void ff_decode_pitch_lag(int *lag_int, int *lag_frac, int pitch_index, 145 const int prev_lag_int, const int subframe, 146 int third_as_first, int resolution) 147{ 148 /* Note n * 10923 >> 15 is floor(x/3) for 0 <= n <= 32767 */ 149 if (subframe == 0 || (subframe == 2 && third_as_first)) { 150 151 if (pitch_index < 197) 152 pitch_index += 59; 153 else 154 pitch_index = 3 * pitch_index - 335; 155 156 } else { 157 if (resolution == 4) { 158 int search_range_min = av_clip(prev_lag_int - 5, PITCH_DELAY_MIN, 159 PITCH_DELAY_MAX - 9); 160 161 // decoding with 4-bit resolution 162 if (pitch_index < 4) { 163 // integer only precision for [search_range_min, search_range_min+3] 164 pitch_index = 3 * (pitch_index + search_range_min) + 1; 165 } else if (pitch_index < 12) { 166 // 1/3 fractional precision for [search_range_min+3 1/3, search_range_min+5 2/3] 167 pitch_index += 3 * search_range_min + 7; 168 } else { 169 // integer only precision for [search_range_min+6, search_range_min+9] 170 pitch_index = 3 * (pitch_index + search_range_min - 6) + 1; 171 } 172 } else { 173 // decoding with 5 or 6 bit resolution, 1/3 fractional precision 174 pitch_index--; 175 176 if (resolution == 5) { 177 pitch_index += 3 * av_clip(prev_lag_int - 10, PITCH_DELAY_MIN, 178 PITCH_DELAY_MAX - 19); 179 } else 180 pitch_index += 3 * av_clip(prev_lag_int - 5, PITCH_DELAY_MIN, 181 PITCH_DELAY_MAX - 9); 182 } 183 } 184 *lag_int = pitch_index * 10923 >> 15; 185 *lag_frac = pitch_index - 3 * *lag_int - 1; 186} 187