blob: 8ec1ba3a8396b827a19b7e573aad296502249b8a
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); |
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 | } |
191 |