jpegdec: be less picky on padding
[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/libm.h"
26 #include "libavutil/mathematics.h"
27 #include "avcodec.h"
28 #include "acelp_pitch_delay.h"
29 #include "celp_math.h"
30
31 int ff_acelp_decode_8bit_to_1st_delay3(int ac_index)
32 {
33     ac_index += 58;
34     if(ac_index > 254)
35         ac_index = 3 * ac_index - 510;
36     return ac_index;
37 }
38
39 int ff_acelp_decode_4bit_to_2nd_delay3(
40         int ac_index,
41         int pitch_delay_min)
42 {
43     if(ac_index < 4)
44         return 3 * (ac_index + pitch_delay_min);
45     else if(ac_index < 12)
46         return 3 * pitch_delay_min + ac_index + 6;
47     else
48         return 3 * (ac_index + pitch_delay_min) - 18;
49 }
50
51 int ff_acelp_decode_5_6_bit_to_2nd_delay3(
52         int ac_index,
53         int pitch_delay_min)
54 {
55         return 3 * pitch_delay_min + ac_index - 2;
56 }
57
58 int ff_acelp_decode_9bit_to_1st_delay6(int ac_index)
59 {
60     if(ac_index < 463)
61         return ac_index + 105;
62     else
63         return 6 * (ac_index - 368);
64 }
65 int ff_acelp_decode_6bit_to_2nd_delay6(
66         int ac_index,
67         int pitch_delay_min)
68 {
69     return 6 * pitch_delay_min + ac_index - 3;
70 }
71
72 void ff_acelp_update_past_gain(
73     int16_t* quant_energy,
74     int gain_corr_factor,
75     int log2_ma_pred_order,
76     int erasure)
77 {
78     int i;
79     int avg_gain=quant_energy[(1 << log2_ma_pred_order) - 1]; // (5.10)
80
81     for(i=(1 << log2_ma_pred_order) - 1; i>0; i--)
82     {
83         avg_gain       += quant_energy[i-1];
84         quant_energy[i] = quant_energy[i-1];
85     }
86
87     if(erasure)
88         quant_energy[0] = FFMAX(avg_gain >> log2_ma_pred_order, -10240) - 4096; // -10 and -4 in (5.10)
89     else
90         quant_energy[0] = (6165 * ((ff_log2_q15(gain_corr_factor) >> 2) - (13 << 13))) >> 13;
91 }
92
93 int16_t ff_acelp_decode_gain_code(
94     DSPContext *dsp,
95     int gain_corr_factor,
96     const int16_t* fc_v,
97     int mr_energy,
98     const int16_t* quant_energy,
99     const int16_t* ma_prediction_coeff,
100     int subframe_size,
101     int ma_pred_order)
102 {
103     int i;
104
105     mr_energy <<= 10;
106
107     for(i=0; i<ma_pred_order; i++)
108         mr_energy += quant_energy[i] * ma_prediction_coeff[i];
109
110 #ifdef G729_BITEXACT
111     mr_energy += (((-6165LL * ff_log2(dsp->scalarproduct_int16(fc_v, fc_v, subframe_size, 0))) >> 3) & ~0x3ff);
112
113     mr_energy = (5439 * (mr_energy >> 15)) >> 8;           // (0.15) = (0.15) * (7.23)
114
115     return bidir_sal(
116                ((ff_exp2(mr_energy & 0x7fff) + 16) >> 5) * (gain_corr_factor >> 1),
117                (mr_energy >> 15) - 25
118            );
119 #else
120     mr_energy = gain_corr_factor * exp(M_LN10 / (20 << 23) * mr_energy) /
121                 sqrt(dsp->scalarproduct_int16(fc_v, fc_v, subframe_size));
122     return mr_energy >> 12;
123 #endif
124 }
125
126 float ff_amr_set_fixed_gain(float fixed_gain_factor, float fixed_mean_energy,
127                             float *prediction_error, float energy_mean,
128                             const float *pred_table)
129 {
130     // Equations 66-69:
131     // ^g_c = ^gamma_gc * 100.05 (predicted dB + mean dB - dB of fixed vector)
132     // Note 10^(0.05 * -10log(average x2)) = 1/sqrt((average x2)).
133     float val = fixed_gain_factor *
134         exp2f(M_LOG2_10 * 0.05 *
135               (avpriv_scalarproduct_float_c(pred_table, prediction_error, 4) +
136                energy_mean)) /
137         sqrtf(fixed_mean_energy);
138
139     // update quantified prediction error energy history
140     memmove(&prediction_error[0], &prediction_error[1],
141             3 * sizeof(prediction_error[0]));
142     prediction_error[3] = 20.0 * log10f(fixed_gain_factor);
143
144     return val;
145 }
146
147 void ff_decode_pitch_lag(int *lag_int, int *lag_frac, int pitch_index,
148                          const int prev_lag_int, const int subframe,
149                          int third_as_first, int resolution)
150 {
151     /* Note n * 10923 >> 15 is floor(x/3) for 0 <= n <= 32767 */
152     if (subframe == 0 || (subframe == 2 && third_as_first)) {
153
154         if (pitch_index < 197)
155             pitch_index += 59;
156         else
157             pitch_index = 3 * pitch_index - 335;
158
159     } else {
160         if (resolution == 4) {
161             int search_range_min = av_clip(prev_lag_int - 5, PITCH_DELAY_MIN,
162                                            PITCH_DELAY_MAX - 9);
163
164             // decoding with 4-bit resolution
165             if (pitch_index < 4) {
166                 // integer only precision for [search_range_min, search_range_min+3]
167                 pitch_index = 3 * (pitch_index + search_range_min) + 1;
168             } else if (pitch_index < 12) {
169                 // 1/3 fractional precision for [search_range_min+3 1/3, search_range_min+5 2/3]
170                 pitch_index += 3 * search_range_min + 7;
171             } else {
172                 // integer only precision for [search_range_min+6, search_range_min+9]
173                 pitch_index = 3 * (pitch_index + search_range_min - 6) + 1;
174             }
175         } else {
176             // decoding with 5 or 6 bit resolution, 1/3 fractional precision
177             pitch_index--;
178
179             if (resolution == 5) {
180                 pitch_index += 3 * av_clip(prev_lag_int - 10, PITCH_DELAY_MIN,
181                                            PITCH_DELAY_MAX - 19);
182             } else
183                 pitch_index += 3 * av_clip(prev_lag_int - 5, PITCH_DELAY_MIN,
184                                            PITCH_DELAY_MAX - 9);
185         }
186     }
187     *lag_int  = pitch_index * 10923 >> 15;
188     *lag_frac = pitch_index - 3 * *lag_int - 1;
189 }