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
29
31 int16_t* quant_energy,
32 int gain_corr_factor,
33 int log2_ma_pred_order,
34 int erasure)
35 {
37 int avg_gain=quant_energy[(1 << log2_ma_pred_order) - 1]; // (5.10)
38
39 for(
i=(1 << log2_ma_pred_order) - 1;
i>0;
i--)
40 {
41 avg_gain += quant_energy[
i-1];
42 quant_energy[
i] = quant_energy[
i-1];
43 }
44
45 if(erasure)
46 quant_energy[0] =
FFMAX(avg_gain >> log2_ma_pred_order, -10240) - 4096;
// -10 and -4 in (5.10)
47 else
48 quant_energy[0] = (6165 * ((
ff_log2_q15(gain_corr_factor) >> 2) - (13 << 13))) >> 13;
49 }
50
53 int gain_corr_factor,
54 const int16_t* fc_v,
55 int mr_energy,
56 const int16_t* quant_energy,
58 int subframe_size,
59 int ma_pred_order)
60 {
62
63 mr_energy <<= 10;
64
65 for(
i=0;
i<ma_pred_order;
i++)
67
68 #ifdef G729_BITEXACT
69 mr_energy += (((-6165LL *
ff_log2(dsp->scalarproduct_int16(fc_v, fc_v, subframe_size, 0))) >> 3) & ~0x3ff);
70
71 mr_energy = (5439 * (mr_energy >> 15)) >> 8; // (0.15) = (0.15) * (7.23)
72
74 ((
ff_exp2(mr_energy & 0x7fff) + 16) >> 5) * (gain_corr_factor >> 1),
75 (mr_energy >> 15) - 25
76 );
77 #else
78 mr_energy = gain_corr_factor *
ff_exp10((
double)mr_energy / (20 << 23)) /
80 return mr_energy >> 12;
81 #endif
82 }
83
86 const float *pred_table)
87 {
88 // Equations 66-69:
89 // ^g_c = ^gamma_gc * 100.05 (predicted dB + mean dB - dB of fixed vector)
90 // Note 10^(0.05 * -10log(average x2)) = 1/sqrt((average x2)).
91 float val = fixed_gain_factor *
95 sqrtf(fixed_mean_energy ? fixed_mean_energy : 1.0);
96
97 // update quantified prediction error energy history
98 memmove(&prediction_error[0], &prediction_error[1],
99 3 * sizeof(prediction_error[0]));
100 prediction_error[3] = 20.0 *
log10f(fixed_gain_factor);
101
103 }
104
106 const int prev_lag_int, const int subframe,
108 {
109 /* Note n * 10923 >> 15 is floor(x/3) for 0 <= n <= 32767 */
110 if (subframe == 0 || (subframe == 2 && third_as_first)) {
111
112 if (pitch_index < 197)
113 pitch_index += 59;
114 else
115 pitch_index = 3 * pitch_index - 335;
116
117 } else {
121
122 // decoding with 4-bit resolution
123 if (pitch_index < 4) {
124 // integer only precision for [search_range_min, search_range_min+3]
125 pitch_index = 3 * (pitch_index + search_range_min) + 1;
126 } else if (pitch_index < 12) {
127 // 1/3 fractional precision for [search_range_min+3 1/3, search_range_min+5 2/3]
128 pitch_index += 3 * search_range_min + 7;
129 } else {
130 // integer only precision for [search_range_min+6, search_range_min+9]
131 pitch_index = 3 * (pitch_index + search_range_min - 6) + 1;
132 }
133 } else {
134 // decoding with 5 or 6 bit resolution, 1/3 fractional precision
135 pitch_index--;
136
140 } else
143 }
144 }
145 *lag_int = pitch_index * 10923 >> 15;
146 *lag_frac = pitch_index - 3 * *lag_int - 1;
147 }