c2533b1eb1a6dbe2296d6d7f6b9149e52ef3248e
[ffmpeg.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 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 "libavutil/common.h"
24 #include "libavutil/float_dsp.h"
25 #include "libavutil/internal.h"
26 #include "libavutil/libm.h"
27 #include "libavutil/mathematics.h"
28 #include "avcodec.h"
29 #include "acelp_pitch_delay.h"
30 #include "celp_math.h"
31 #include "audiodsp.h"
32
33 int ff_acelp_decode_8bit_to_1st_delay3(int ac_index)
34 {
35     ac_index += 58;
36     if(ac_index > 254)
37         ac_index = 3 * ac_index - 510;
38     return ac_index;
39 }
40
41 int ff_acelp_decode_4bit_to_2nd_delay3(
42         int ac_index,
43         int pitch_delay_min)
44 {
45     if(ac_index < 4)
46         return 3 * (ac_index + pitch_delay_min);
47     else if(ac_index < 12)
48         return 3 * pitch_delay_min + ac_index + 6;
49     else
50         return 3 * (ac_index + pitch_delay_min) - 18;
51 }
52
53 int ff_acelp_decode_5_6_bit_to_2nd_delay3(
54         int ac_index,
55         int pitch_delay_min)
56 {
57         return 3 * pitch_delay_min + ac_index - 2;
58 }
59
60 int ff_acelp_decode_9bit_to_1st_delay6(int ac_index)
61 {
62     if(ac_index < 463)
63         return ac_index + 105;
64     else
65         return 6 * (ac_index - 368);
66 }
67 int ff_acelp_decode_6bit_to_2nd_delay6(
68         int ac_index,
69         int pitch_delay_min)
70 {
71     return 6 * pitch_delay_min + ac_index - 3;
72 }
73
74 void ff_acelp_update_past_gain(
75     int16_t* quant_energy,
76     int gain_corr_factor,
77     int log2_ma_pred_order,
78     int erasure)
79 {
80     int i;
81     int avg_gain=quant_energy[(1 << log2_ma_pred_order) - 1]; // (5.10)
82
83     for(i=(1 << log2_ma_pred_order) - 1; i>0; i--)
84     {
85         avg_gain       += quant_energy[i-1];
86         quant_energy[i] = quant_energy[i-1];
87     }
88
89     if(erasure)
90         quant_energy[0] = FFMAX(avg_gain >> log2_ma_pred_order, -10240) - 4096; // -10 and -4 in (5.10)
91     else
92         quant_energy[0] = (6165 * ((ff_log2_q15(gain_corr_factor) >> 2) - (13 << 13))) >> 13;
93 }
94
95 int16_t ff_acelp_decode_gain_code(
96     AudioDSPContext *adsp,
97     int gain_corr_factor,
98     const int16_t* fc_v,
99     int mr_energy,
100     const int16_t* quant_energy,
101     const int16_t* ma_prediction_coeff,
102     int subframe_size,
103     int ma_pred_order)
104 {
105     int i;
106
107     mr_energy <<= 10;
108
109     for(i=0; i<ma_pred_order; i++)
110         mr_energy += quant_energy[i] * ma_prediction_coeff[i];
111
112 #ifdef G729_BITEXACT
113     mr_energy += (((-6165LL * ff_log2(dsp->scalarproduct_int16(fc_v, fc_v, subframe_size, 0))) >> 3) & ~0x3ff);
114
115     mr_energy = (5439 * (mr_energy >> 15)) >> 8;           // (0.15) = (0.15) * (7.23)
116
117     return bidir_sal(
118                ((ff_exp2(mr_energy & 0x7fff) + 16) >> 5) * (gain_corr_factor >> 1),
119                (mr_energy >> 15) - 25
120            );
121 #else
122     mr_energy = gain_corr_factor * exp(M_LN10 / (20 << 23) * mr_energy) /
123                 sqrt(adsp->scalarproduct_int16(fc_v, fc_v, subframe_size));
124     return mr_energy >> 12;
125 #endif
126 }
127
128 float ff_amr_set_fixed_gain(float fixed_gain_factor, float fixed_mean_energy,
129                             float *prediction_error, float energy_mean,
130                             const float *pred_table)
131 {
132     // Equations 66-69:
133     // ^g_c = ^gamma_gc * 100.05 (predicted dB + mean dB - dB of fixed vector)
134     // Note 10^(0.05 * -10log(average x2)) = 1/sqrt((average x2)).
135     float val = fixed_gain_factor *
136         ff_exp10(0.05 *
137               (avpriv_scalarproduct_float_c(pred_table, prediction_error, 4) +
138                energy_mean)) /
139         sqrtf(fixed_mean_energy);
140
141     // update quantified prediction error energy history
142     memmove(&prediction_error[0], &prediction_error[1],
143             3 * sizeof(prediction_error[0]));
144     prediction_error[3] = 20.0 * log10f(fixed_gain_factor);
145
146     return val;
147 }
148
149 void ff_decode_pitch_lag(int *lag_int, int *lag_frac, int pitch_index,
150                          const int prev_lag_int, const int subframe,
151                          int third_as_first, int resolution)
152 {
153     /* Note n * 10923 >> 15 is floor(x/3) for 0 <= n <= 32767 */
154     if (subframe == 0 || (subframe == 2 && third_as_first)) {
155
156         if (pitch_index < 197)
157             pitch_index += 59;
158         else
159             pitch_index = 3 * pitch_index - 335;
160
161     } else {
162         if (resolution == 4) {
163             int search_range_min = av_clip(prev_lag_int - 5, PITCH_DELAY_MIN,
164                                            PITCH_DELAY_MAX - 9);
165
166             // decoding with 4-bit resolution
167             if (pitch_index < 4) {
168                 // integer only precision for [search_range_min, search_range_min+3]
169                 pitch_index = 3 * (pitch_index + search_range_min) + 1;
170             } else if (pitch_index < 12) {
171                 // 1/3 fractional precision for [search_range_min+3 1/3, search_range_min+5 2/3]
172                 pitch_index += 3 * search_range_min + 7;
173             } else {
174                 // integer only precision for [search_range_min+6, search_range_min+9]
175                 pitch_index = 3 * (pitch_index + search_range_min - 6) + 1;
176             }
177         } else {
178             // decoding with 5 or 6 bit resolution, 1/3 fractional precision
179             pitch_index--;
180
181             if (resolution == 5) {
182                 pitch_index += 3 * av_clip(prev_lag_int - 10, PITCH_DELAY_MIN,
183                                            PITCH_DELAY_MAX - 19);
184             } else
185                 pitch_index += 3 * av_clip(prev_lag_int - 5, PITCH_DELAY_MIN,
186                                            PITCH_DELAY_MAX - 9);
187         }
188     }
189     *lag_int  = pitch_index * 10923 >> 15;
190     *lag_frac = pitch_index - 3 * *lag_int - 1;
191 }