celp_math: rename ff_log2 to ff_log2_q15
[libav.git] / libavcodec / acelp_pitch_delay.c
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/common.h"
24 #include "libavutil/mathematics.h"
25 #include "avcodec.h"
26 #include "dsputil.h"
27 #include "acelp_pitch_delay.h"
28 #include "celp_math.h"
29
30 int ff_acelp_decode_8bit_to_1st_delay3(int ac_index)
31 {
32 ac_index += 58;
33 if(ac_index > 254)
34 ac_index = 3 * ac_index - 510;
35 return ac_index;
36 }
37
38 int ff_acelp_decode_4bit_to_2nd_delay3(
39 int ac_index,
40 int pitch_delay_min)
41 {
42 if(ac_index < 4)
43 return 3 * (ac_index + pitch_delay_min);
44 else if(ac_index < 12)
45 return 3 * pitch_delay_min + ac_index + 6;
46 else
47 return 3 * (ac_index + pitch_delay_min) - 18;
48 }
49
50 int ff_acelp_decode_5_6_bit_to_2nd_delay3(
51 int ac_index,
52 int pitch_delay_min)
53 {
54 return 3 * pitch_delay_min + ac_index - 2;
55 }
56
57 int ff_acelp_decode_9bit_to_1st_delay6(int ac_index)
58 {
59 if(ac_index < 463)
60 return ac_index + 105;
61 else
62 return 6 * (ac_index - 368);
63 }
64 int ff_acelp_decode_6bit_to_2nd_delay6(
65 int ac_index,
66 int pitch_delay_min)
67 {
68 return 6 * pitch_delay_min + ac_index - 3;
69 }
70
71 void ff_acelp_update_past_gain(
72 int16_t* quant_energy,
73 int gain_corr_factor,
74 int log2_ma_pred_order,
75 int erasure)
76 {
77 int i;
78 int avg_gain=quant_energy[(1 << log2_ma_pred_order) - 1]; // (5.10)
79
80 for(i=(1 << log2_ma_pred_order) - 1; i>0; i--)
81 {
82 avg_gain += quant_energy[i-1];
83 quant_energy[i] = quant_energy[i-1];
84 }
85
86 if(erasure)
87 quant_energy[0] = FFMAX(avg_gain >> log2_ma_pred_order, -10240) - 4096; // -10 and -4 in (5.10)
88 else
89 quant_energy[0] = (6165 * ((ff_log2_q15(gain_corr_factor) >> 2) - (13 << 13))) >> 13;
90 }
91
92 int16_t ff_acelp_decode_gain_code(
93 DSPContext *dsp,
94 int gain_corr_factor,
95 const int16_t* fc_v,
96 int mr_energy,
97 const int16_t* quant_energy,
98 const int16_t* ma_prediction_coeff,
99 int subframe_size,
100 int ma_pred_order)
101 {
102 int i;
103
104 mr_energy <<= 10;
105
106 for(i=0; i<ma_pred_order; i++)
107 mr_energy += quant_energy[i] * ma_prediction_coeff[i];
108
109 mr_energy = gain_corr_factor * exp(M_LN10 / (20 << 23) * mr_energy) /
110 sqrt(dsp->scalarproduct_int16(fc_v, fc_v, subframe_size));
111 return mr_energy >> 12;
112 }
113
114 float ff_amr_set_fixed_gain(float fixed_gain_factor, float fixed_mean_energy,
115 float *prediction_error, float energy_mean,
116 const float *pred_table)
117 {
118 // Equations 66-69:
119 // ^g_c = ^gamma_gc * 100.05 (predicted dB + mean dB - dB of fixed vector)
120 // Note 10^(0.05 * -10log(average x2)) = 1/sqrt((average x2)).
121 float val = fixed_gain_factor *
122 exp2f(M_LOG2_10 * 0.05 *
123 (ff_scalarproduct_float_c(pred_table, prediction_error, 4) +
124 energy_mean)) /
125 sqrtf(fixed_mean_energy);
126
127 // update quantified prediction error energy history
128 memmove(&prediction_error[0], &prediction_error[1],
129 3 * sizeof(prediction_error[0]));
130 prediction_error[3] = 20.0 * log10f(fixed_gain_factor);
131
132 return val;
133 }
134
135 void ff_decode_pitch_lag(int *lag_int, int *lag_frac, int pitch_index,
136 const int prev_lag_int, const int subframe,
137 int third_as_first, int resolution)
138 {
139 /* Note n * 10923 >> 15 is floor(x/3) for 0 <= n <= 32767 */
140 if (subframe == 0 || (subframe == 2 && third_as_first)) {
141
142 if (pitch_index < 197)
143 pitch_index += 59;
144 else
145 pitch_index = 3 * pitch_index - 335;
146
147 } else {
148 if (resolution == 4) {
149 int search_range_min = av_clip(prev_lag_int - 5, PITCH_DELAY_MIN,
150 PITCH_DELAY_MAX - 9);
151
152 // decoding with 4-bit resolution
153 if (pitch_index < 4) {
154 // integer only precision for [search_range_min, search_range_min+3]
155 pitch_index = 3 * (pitch_index + search_range_min) + 1;
156 } else if (pitch_index < 12) {
157 // 1/3 fractional precision for [search_range_min+3 1/3, search_range_min+5 2/3]
158 pitch_index += 3 * search_range_min + 7;
159 } else {
160 // integer only precision for [search_range_min+6, search_range_min+9]
161 pitch_index = 3 * (pitch_index + search_range_min - 6) + 1;
162 }
163 } else {
164 // decoding with 5 or 6 bit resolution, 1/3 fractional precision
165 pitch_index--;
166
167 if (resolution == 5) {
168 pitch_index += 3 * av_clip(prev_lag_int - 10, PITCH_DELAY_MIN,
169 PITCH_DELAY_MAX - 19);
170 } else
171 pitch_index += 3 * av_clip(prev_lag_int - 5, PITCH_DELAY_MIN,
172 PITCH_DELAY_MAX - 9);
173 }
174 }
175 *lag_int = pitch_index * 10923 >> 15;
176 *lag_frac = pitch_index - 3 * *lag_int - 1;
177 }