/* * gain code, gain pitch and pitch delay decoding * * Copyright (c) 2008 Vladimir Voroshilov * * This file is part of FFmpeg. * * FFmpeg is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * FFmpeg 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 * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with FFmpeg; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ #include "libavutil/common.h" #include "libavutil/float_dsp.h" #include "libavutil/libm.h" #include "libavutil/mathematics.h" #include "avcodec.h" #include "acelp_pitch_delay.h" #include "celp_math.h" int ff_acelp_decode_8bit_to_1st_delay3(int ac_index) { ac_index += 58; if(ac_index > 254) ac_index = 3 * ac_index - 510; return ac_index; } int ff_acelp_decode_4bit_to_2nd_delay3( int ac_index, int pitch_delay_min) { if(ac_index < 4) return 3 * (ac_index + pitch_delay_min); else if(ac_index < 12) return 3 * pitch_delay_min + ac_index + 6; else return 3 * (ac_index + pitch_delay_min) - 18; } int ff_acelp_decode_5_6_bit_to_2nd_delay3( int ac_index, int pitch_delay_min) { return 3 * pitch_delay_min + ac_index - 2; } int ff_acelp_decode_9bit_to_1st_delay6(int ac_index) { if(ac_index < 463) return ac_index + 105; else return 6 * (ac_index - 368); } int ff_acelp_decode_6bit_to_2nd_delay6( int ac_index, int pitch_delay_min) { return 6 * pitch_delay_min + ac_index - 3; } void ff_acelp_update_past_gain( int16_t* quant_energy, int gain_corr_factor, int log2_ma_pred_order, int erasure) { int i; int avg_gain=quant_energy[(1 << log2_ma_pred_order) - 1]; // (5.10) for(i=(1 << log2_ma_pred_order) - 1; i>0; i--) { avg_gain += quant_energy[i-1]; quant_energy[i] = quant_energy[i-1]; } if(erasure) quant_energy[0] = FFMAX(avg_gain >> log2_ma_pred_order, -10240) - 4096; // -10 and -4 in (5.10) else quant_energy[0] = (6165 * ((ff_log2_q15(gain_corr_factor) >> 2) - (13 << 13))) >> 13; } int16_t ff_acelp_decode_gain_code( DSPContext *dsp, int gain_corr_factor, const int16_t* fc_v, int mr_energy, const int16_t* quant_energy, const int16_t* ma_prediction_coeff, int subframe_size, int ma_pred_order) { int i; mr_energy <<= 10; for(i=0; i<ma_pred_order; i++) mr_energy += quant_energy[i] * ma_prediction_coeff[i]; #ifdef G729_BITEXACT mr_energy += (((-6165LL * ff_log2(dsp->scalarproduct_int16(fc_v, fc_v, subframe_size, 0))) >> 3) & ~0x3ff); mr_energy = (5439 * (mr_energy >> 15)) >> 8; // (0.15) = (0.15) * (7.23) return bidir_sal( ((ff_exp2(mr_energy & 0x7fff) + 16) >> 5) * (gain_corr_factor >> 1), (mr_energy >> 15) - 25 ); #else mr_energy = gain_corr_factor * exp(M_LN10 / (20 << 23) * mr_energy) / sqrt(dsp->scalarproduct_int16(fc_v, fc_v, subframe_size)); return mr_energy >> 12; #endif } float ff_amr_set_fixed_gain(float fixed_gain_factor, float fixed_mean_energy, float *prediction_error, float energy_mean, const float *pred_table) { // Equations 66-69: // ^g_c = ^gamma_gc * 100.05 (predicted dB + mean dB - dB of fixed vector) // Note 10^(0.05 * -10log(average x2)) = 1/sqrt((average x2)). float val = fixed_gain_factor * exp2f(M_LOG2_10 * 0.05 * (avpriv_scalarproduct_float_c(pred_table, prediction_error, 4) + energy_mean)) / sqrtf(fixed_mean_energy); // update quantified prediction error energy history memmove(&prediction_error[0], &prediction_error[1], 3 * sizeof(prediction_error[0])); prediction_error[3] = 20.0 * log10f(fixed_gain_factor); return val; } void ff_decode_pitch_lag(int *lag_int, int *lag_frac, int pitch_index, const int prev_lag_int, const int subframe, int third_as_first, int resolution) { /* Note n * 10923 >> 15 is floor(x/3) for 0 <= n <= 32767 */ if (subframe == 0 || (subframe == 2 && third_as_first)) { if (pitch_index < 197) pitch_index += 59; else pitch_index = 3 * pitch_index - 335; } else { if (resolution == 4) { int search_range_min = av_clip(prev_lag_int - 5, PITCH_DELAY_MIN, PITCH_DELAY_MAX - 9); // decoding with 4-bit resolution if (pitch_index < 4) { // integer only precision for [search_range_min, search_range_min+3] pitch_index = 3 * (pitch_index + search_range_min) + 1; } else if (pitch_index < 12) { // 1/3 fractional precision for [search_range_min+3 1/3, search_range_min+5 2/3] pitch_index += 3 * search_range_min + 7; } else { // integer only precision for [search_range_min+6, search_range_min+9] pitch_index = 3 * (pitch_index + search_range_min - 6) + 1; } } else { // decoding with 5 or 6 bit resolution, 1/3 fractional precision pitch_index--; if (resolution == 5) { pitch_index += 3 * av_clip(prev_lag_int - 10, PITCH_DELAY_MIN, PITCH_DELAY_MAX - 19); } else pitch_index += 3 * av_clip(prev_lag_int - 5, PITCH_DELAY_MIN, PITCH_DELAY_MAX - 9); } } *lag_int = pitch_index * 10923 >> 15; *lag_frac = pitch_index - 3 * *lag_int - 1; }