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1 | /* |
2 | * various filters for ACELP-based codecs | |
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 <inttypes.h> | |
24 | ||
25 | #include "avcodec.h" | |
26 | #include "celp_filters.h" | |
27 | #include "libavutil/avassert.h" | |
28 | #include "libavutil/common.h" | |
29 | ||
30 | void ff_celp_convolve_circ(int16_t* fc_out, const int16_t* fc_in, | |
31 | const int16_t* filter, int len) | |
32 | { | |
33 | int i, k; | |
34 | ||
35 | memset(fc_out, 0, len * sizeof(int16_t)); | |
36 | ||
37 | /* Since there are few pulses over an entire subframe (i.e. almost | |
38 | all fc_in[i] are zero) it is faster to loop over fc_in first. */ | |
39 | for (i = 0; i < len; i++) { | |
40 | if (fc_in[i]) { | |
41 | for (k = 0; k < i; k++) | |
42 | fc_out[k] += (fc_in[i] * filter[len + k - i]) >> 15; | |
43 | ||
44 | for (k = i; k < len; k++) | |
45 | fc_out[k] += (fc_in[i] * filter[ k - i]) >> 15; | |
46 | } | |
47 | } | |
48 | } | |
49 | ||
50 | void ff_celp_circ_addf(float *out, const float *in, | |
51 | const float *lagged, int lag, float fac, int n) | |
52 | { | |
53 | int k; | |
54 | for (k = 0; k < lag; k++) | |
55 | out[k] = in[k] + fac * lagged[n + k - lag]; | |
56 | for (; k < n; k++) | |
57 | out[k] = in[k] + fac * lagged[ k - lag]; | |
58 | } | |
59 | ||
60 | int ff_celp_lp_synthesis_filter(int16_t *out, const int16_t *filter_coeffs, | |
61 | const int16_t *in, int buffer_length, | |
62 | int filter_length, int stop_on_overflow, | |
63 | int shift, int rounder) | |
64 | { | |
65 | int i,n; | |
66 | ||
67 | for (n = 0; n < buffer_length; n++) { | |
68 | int sum = -rounder, sum1; | |
69 | for (i = 1; i <= filter_length; i++) | |
70 | sum += filter_coeffs[i-1] * out[n-i]; | |
71 | ||
72 | sum1 = ((-sum >> 12) + in[n]) >> shift; | |
73 | sum = av_clip_int16(sum1); | |
74 | ||
75 | if (stop_on_overflow && sum != sum1) | |
76 | return 1; | |
77 | ||
78 | out[n] = sum; | |
79 | } | |
80 | ||
81 | return 0; | |
82 | } | |
83 | ||
84 | void ff_celp_lp_synthesis_filterf(float *out, const float *filter_coeffs, | |
85 | const float* in, int buffer_length, | |
86 | int filter_length) | |
87 | { | |
88 | int i,n; | |
89 | ||
90 | #if 0 // Unoptimized code path for improved readability | |
91 | for (n = 0; n < buffer_length; n++) { | |
92 | out[n] = in[n]; | |
93 | for (i = 1; i <= filter_length; i++) | |
94 | out[n] -= filter_coeffs[i-1] * out[n-i]; | |
95 | } | |
96 | #else | |
97 | float out0, out1, out2, out3; | |
98 | float old_out0, old_out1, old_out2, old_out3; | |
99 | float a,b,c; | |
100 | ||
101 | a = filter_coeffs[0]; | |
102 | b = filter_coeffs[1]; | |
103 | c = filter_coeffs[2]; | |
104 | b -= filter_coeffs[0] * filter_coeffs[0]; | |
105 | c -= filter_coeffs[1] * filter_coeffs[0]; | |
106 | c -= filter_coeffs[0] * b; | |
107 | ||
108 | av_assert2((filter_length&1)==0 && filter_length>=4); | |
109 | ||
110 | old_out0 = out[-4]; | |
111 | old_out1 = out[-3]; | |
112 | old_out2 = out[-2]; | |
113 | old_out3 = out[-1]; | |
114 | for (n = 0; n <= buffer_length - 4; n+=4) { | |
115 | float tmp0,tmp1,tmp2; | |
116 | float val; | |
117 | ||
118 | out0 = in[0]; | |
119 | out1 = in[1]; | |
120 | out2 = in[2]; | |
121 | out3 = in[3]; | |
122 | ||
123 | out0 -= filter_coeffs[2] * old_out1; | |
124 | out1 -= filter_coeffs[2] * old_out2; | |
125 | out2 -= filter_coeffs[2] * old_out3; | |
126 | ||
127 | out0 -= filter_coeffs[1] * old_out2; | |
128 | out1 -= filter_coeffs[1] * old_out3; | |
129 | ||
130 | out0 -= filter_coeffs[0] * old_out3; | |
131 | ||
132 | val = filter_coeffs[3]; | |
133 | ||
134 | out0 -= val * old_out0; | |
135 | out1 -= val * old_out1; | |
136 | out2 -= val * old_out2; | |
137 | out3 -= val * old_out3; | |
138 | ||
139 | for (i = 5; i < filter_length; i += 2) { | |
140 | old_out3 = out[-i]; | |
141 | val = filter_coeffs[i-1]; | |
142 | ||
143 | out0 -= val * old_out3; | |
144 | out1 -= val * old_out0; | |
145 | out2 -= val * old_out1; | |
146 | out3 -= val * old_out2; | |
147 | ||
148 | old_out2 = out[-i-1]; | |
149 | ||
150 | val = filter_coeffs[i]; | |
151 | ||
152 | out0 -= val * old_out2; | |
153 | out1 -= val * old_out3; | |
154 | out2 -= val * old_out0; | |
155 | out3 -= val * old_out1; | |
156 | ||
157 | FFSWAP(float, old_out0, old_out2); | |
158 | old_out1 = old_out3; | |
159 | } | |
160 | ||
161 | tmp0 = out0; | |
162 | tmp1 = out1; | |
163 | tmp2 = out2; | |
164 | ||
165 | out3 -= a * tmp2; | |
166 | out2 -= a * tmp1; | |
167 | out1 -= a * tmp0; | |
168 | ||
169 | out3 -= b * tmp1; | |
170 | out2 -= b * tmp0; | |
171 | ||
172 | out3 -= c * tmp0; | |
173 | ||
174 | ||
175 | out[0] = out0; | |
176 | out[1] = out1; | |
177 | out[2] = out2; | |
178 | out[3] = out3; | |
179 | ||
180 | old_out0 = out0; | |
181 | old_out1 = out1; | |
182 | old_out2 = out2; | |
183 | old_out3 = out3; | |
184 | ||
185 | out += 4; | |
186 | in += 4; | |
187 | } | |
188 | ||
189 | out -= n; | |
190 | in -= n; | |
191 | for (; n < buffer_length; n++) { | |
192 | out[n] = in[n]; | |
193 | for (i = 1; i <= filter_length; i++) | |
194 | out[n] -= filter_coeffs[i-1] * out[n-i]; | |
195 | } | |
196 | #endif | |
197 | } | |
198 | ||
199 | void ff_celp_lp_zero_synthesis_filterf(float *out, const float *filter_coeffs, | |
200 | const float *in, int buffer_length, | |
201 | int filter_length) | |
202 | { | |
203 | int i,n; | |
204 | ||
205 | for (n = 0; n < buffer_length; n++) { | |
206 | out[n] = in[n]; | |
207 | for (i = 1; i <= filter_length; i++) | |
208 | out[n] += filter_coeffs[i-1] * in[n-i]; | |
209 | } | |
210 | } | |
211 | ||
212 | void ff_celp_filter_init(CELPFContext *c) | |
213 | { | |
214 | c->celp_lp_synthesis_filterf = ff_celp_lp_synthesis_filterf; | |
215 | c->celp_lp_zero_synthesis_filterf = ff_celp_lp_zero_synthesis_filterf; | |
216 | ||
217 | if(HAVE_MIPSFPU) | |
218 | ff_celp_filter_init_mips(c); | |
219 | } |