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
ff_celp_convolve_circ(int16_t * fc_out,const int16_t * fc_in,const int16_t * filter,int len)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
ff_celp_circ_addf(float * out,const float * in,const float * lagged,int lag,float fac,int n)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
ff_celp_lp_synthesis_filter(int16_t * out,const int16_t * filter_coeffs,const int16_t * in,int buffer_length,int filter_length,int stop_on_overflow,int shift,int rounder)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 -= (unsigned)(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
ff_celp_lp_synthesis_filterf(float * out,const float * filter_coeffs,const float * in,int buffer_length,int filter_length)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
ff_celp_lp_zero_synthesis_filterf(float * out,const float * filter_coeffs,const float * in,int buffer_length,int filter_length)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
ff_celp_filter_init(CELPFContext * c)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 }
220