diff options
Diffstat (limited to 'ffmpeg1/libavcodec/acelp_pitch_delay.c')
| -rw-r--r-- | ffmpeg1/libavcodec/acelp_pitch_delay.c | 189 |
1 files changed, 189 insertions, 0 deletions
diff --git a/ffmpeg1/libavcodec/acelp_pitch_delay.c b/ffmpeg1/libavcodec/acelp_pitch_delay.c new file mode 100644 index 0000000..c005c4b --- /dev/null +++ b/ffmpeg1/libavcodec/acelp_pitch_delay.c @@ -0,0 +1,189 @@ +/* + * 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; +} |