avcodec/dca: avoid using bitstream reader in a non-standard way
[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/ffmath.h"
25 #include "libavutil/float_dsp.h"
26 #include "libavutil/mathematics.h"
27 #include "avcodec.h"
28 #include "acelp_pitch_delay.h"
29 #include "celp_math.h"
30 #include "audiodsp.h"
31
32 int ff_acelp_decode_8bit_to_1st_delay3(int ac_index)
33 {
34     ac_index += 58;
35     if(ac_index > 254)
36         ac_index = 3 * ac_index - 510;
37     return ac_index;
38 }
39
40 int ff_acelp_decode_4bit_to_2nd_delay3(
41         int ac_index,
42         int pitch_delay_min)
43 {
44     if(ac_index < 4)
45         return 3 * (ac_index + pitch_delay_min);
46     else if(ac_index < 12)
47         return 3 * pitch_delay_min + ac_index + 6;
48     else
49         return 3 * (ac_index + pitch_delay_min) - 18;
50 }
51
52 int ff_acelp_decode_5_6_bit_to_2nd_delay3(
53         int ac_index,
54         int pitch_delay_min)
55 {
56         return 3 * pitch_delay_min + ac_index - 2;
57 }
58
59 int ff_acelp_decode_9bit_to_1st_delay6(int ac_index)
60 {
61     if(ac_index < 463)
62         return ac_index + 105;
63     else
64         return 6 * (ac_index - 368);
65 }
66 int ff_acelp_decode_6bit_to_2nd_delay6(
67         int ac_index,
68         int pitch_delay_min)
69 {
70     return 6 * pitch_delay_min + ac_index - 3;
71 }
72
73 void ff_acelp_update_past_gain(
74     int16_t* quant_energy,
75     int gain_corr_factor,
76     int log2_ma_pred_order,
77     int erasure)
78 {
79     int i;
80     int avg_gain=quant_energy[(1 << log2_ma_pred_order) - 1]; // (5.10)
81
82     for(i=(1 << log2_ma_pred_order) - 1; i>0; i--)
83     {
84         avg_gain       += quant_energy[i-1];
85         quant_energy[i] = quant_energy[i-1];
86     }
87
88     if(erasure)
89         quant_energy[0] = FFMAX(avg_gain >> log2_ma_pred_order, -10240) - 4096; // -10 and -4 in (5.10)
90     else
91         quant_energy[0] = (6165 * ((ff_log2_q15(gain_corr_factor) >> 2) - (13 << 13))) >> 13;
92 }
93
94 int16_t ff_acelp_decode_gain_code(
95     AudioDSPContext *adsp,
96     int gain_corr_factor,
97     const int16_t* fc_v,
98     int mr_energy,
99     const int16_t* quant_energy,
100     const int16_t* ma_prediction_coeff,
101     int subframe_size,
102     int ma_pred_order)
103 {
104     int i;
105
106     mr_energy <<= 10;
107
108     for(i=0; i<ma_pred_order; i++)
109         mr_energy += quant_energy[i] * ma_prediction_coeff[i];
110
111 #ifdef G729_BITEXACT
112     mr_energy += (((-6165LL * ff_log2(dsp->scalarproduct_int16(fc_v, fc_v, subframe_size, 0))) >> 3) & ~0x3ff);
113
114     mr_energy = (5439 * (mr_energy >> 15)) >> 8;           // (0.15) = (0.15) * (7.23)
115
116     return bidir_sal(
117                ((ff_exp2(mr_energy & 0x7fff) + 16) >> 5) * (gain_corr_factor >> 1),
118                (mr_energy >> 15) - 25
119            );
120 #else
121     mr_energy = gain_corr_factor * exp(M_LN10 / (20 << 23) * mr_energy) /
122                 sqrt(adsp->scalarproduct_int16(fc_v, fc_v, subframe_size));
123     return mr_energy >> 12;
124 #endif
125 }
126
127 float ff_amr_set_fixed_gain(float fixed_gain_factor, float fixed_mean_energy,
128                             float *prediction_error, float energy_mean,
129                             const float *pred_table)
130 {
131     // Equations 66-69:
132     // ^g_c = ^gamma_gc * 100.05 (predicted dB + mean dB - dB of fixed vector)
133     // Note 10^(0.05 * -10log(average x2)) = 1/sqrt((average x2)).
134     float val = fixed_gain_factor *
135         ff_exp10(0.05 *
136               (avpriv_scalarproduct_float_c(pred_table, prediction_error, 4) +
137                energy_mean)) /
138         sqrtf(fixed_mean_energy ? fixed_mean_energy : 1.0);
139
140     // update quantified prediction error energy history
141     memmove(&prediction_error[0], &prediction_error[1],
142             3 * sizeof(prediction_error[0]));
143     prediction_error[3] = 20.0 * log10f(fixed_gain_factor);
144
145     return val;
146 }
147
148 void ff_decode_pitch_lag(int *lag_int, int *lag_frac, int pitch_index,
149                          const int prev_lag_int, const int subframe,
150                          int third_as_first, int resolution)
151 {
152     /* Note n * 10923 >> 15 is floor(x/3) for 0 <= n <= 32767 */
153     if (subframe == 0 || (subframe == 2 && third_as_first)) {
154
155         if (pitch_index < 197)
156             pitch_index += 59;
157         else
158             pitch_index = 3 * pitch_index - 335;
159
160     } else {
161         if (resolution == 4) {
162             int search_range_min = av_clip(prev_lag_int - 5, PITCH_DELAY_MIN,
163                                            PITCH_DELAY_MAX - 9);
164
165             // decoding with 4-bit resolution
166             if (pitch_index < 4) {
167                 // integer only precision for [search_range_min, search_range_min+3]
168                 pitch_index = 3 * (pitch_index + search_range_min) + 1;
169             } else if (pitch_index < 12) {
170                 // 1/3 fractional precision for [search_range_min+3 1/3, search_range_min+5 2/3]
171                 pitch_index += 3 * search_range_min + 7;
172             } else {
173                 // integer only precision for [search_range_min+6, search_range_min+9]
174                 pitch_index = 3 * (pitch_index + search_range_min - 6) + 1;
175             }
176         } else {
177             // decoding with 5 or 6 bit resolution, 1/3 fractional precision
178             pitch_index--;
179
180             if (resolution == 5) {
181                 pitch_index += 3 * av_clip(prev_lag_int - 10, PITCH_DELAY_MIN,
182                                            PITCH_DELAY_MAX - 19);
183             } else
184                 pitch_index += 3 * av_clip(prev_lag_int - 5, PITCH_DELAY_MIN,
185                                            PITCH_DELAY_MAX - 9);
186         }
187     }
188     *lag_int  = pitch_index * 10923 >> 15;
189     *lag_frac = pitch_index - 3 * *lag_int - 1;
190 }