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 "libavutil/avassert.h"
26 #include "libavutil/common.h"
27 #include "avcodec.h"
28 #include "acelp_filters.h"
29
30 const int16_t ff_acelp_interp_filter[61] = { /* (0.15) */
31 29443, 28346, 25207, 20449, 14701, 8693,
32 3143, -1352, -4402, -5865, -5850, -4673,
33 -2783, -672, 1211, 2536, 3130, 2991,
34 2259, 1170, 0, -1001, -1652, -1868,
35 -1666, -1147, -464, 218, 756, 1060,
36 1099, 904, 550, 135, -245, -514,
37 -634, -602, -451, -231, 0, 191,
38 308, 340, 296, 198, 78, -36,
39 -120, -163, -165, -132, -79, -19,
40 34, 73, 91, 89, 70, 38,
41 0,
42 };
43
ff_acelp_interpolate(int16_t * out,const int16_t * in,const int16_t * filter_coeffs,int precision,int frac_pos,int filter_length,int length)44 void ff_acelp_interpolate(int16_t* out, const int16_t* in,
45 const int16_t* filter_coeffs, int precision,
46 int frac_pos, int filter_length, int length)
47 {
48 int n, i;
49
50 av_assert1(frac_pos >= 0 && frac_pos < precision);
51
52 for (n = 0; n < length; n++) {
53 int idx = 0;
54 int v = 0x4000;
55
56 for (i = 0; i < filter_length;) {
57
58 /* The reference G.729 and AMR fixed point code performs clipping after
59 each of the two following accumulations.
60 Since clipping affects only the synthetic OVERFLOW test without
61 causing an int type overflow, it was moved outside the loop. */
62
63 /* R(x):=ac_v[-k+x]
64 v += R(n-i)*ff_acelp_interp_filter(t+6i)
65 v += R(n+i+1)*ff_acelp_interp_filter(6-t+6i) */
66
67 v += in[n + i] * filter_coeffs[idx + frac_pos];
68 idx += precision;
69 i++;
70 v += in[n - i] * filter_coeffs[idx - frac_pos];
71 }
72 if (av_clip_int16(v >> 15) != (v >> 15))
73 av_log(NULL, AV_LOG_WARNING, "overflow that would need clipping in ff_acelp_interpolate()\n");
74 out[n] = v >> 15;
75 }
76 }
77
ff_acelp_interpolatef(float * out,const float * in,const float * filter_coeffs,int precision,int frac_pos,int filter_length,int length)78 void ff_acelp_interpolatef(float *out, const float *in,
79 const float *filter_coeffs, int precision,
80 int frac_pos, int filter_length, int length)
81 {
82 int n, i;
83
84 for (n = 0; n < length; n++) {
85 int idx = 0;
86 float v = 0;
87
88 for (i = 0; i < filter_length;) {
89 v += in[n + i] * filter_coeffs[idx + frac_pos];
90 idx += precision;
91 i++;
92 v += in[n - i] * filter_coeffs[idx - frac_pos];
93 }
94 out[n] = v;
95 }
96 }
97
98
ff_acelp_high_pass_filter(int16_t * out,int hpf_f[2],const int16_t * in,int length)99 void ff_acelp_high_pass_filter(int16_t* out, int hpf_f[2],
100 const int16_t* in, int length)
101 {
102 int i;
103 int tmp;
104
105 for (i = 0; i < length; i++) {
106 tmp = (hpf_f[0]* 15836LL) >> 13;
107 tmp += (hpf_f[1]* -7667LL) >> 13;
108 tmp += 7699 * (in[i] - 2*in[i-1] + in[i-2]);
109
110 /* With "+0x800" rounding, clipping is needed
111 for ALGTHM and SPEECH tests. */
112 out[i] = av_clip_int16((tmp + 0x800) >> 12);
113
114 hpf_f[1] = hpf_f[0];
115 hpf_f[0] = tmp;
116 }
117 }
118
ff_acelp_apply_order_2_transfer_function(float * out,const float * in,const float zero_coeffs[2],const float pole_coeffs[2],float gain,float mem[2],int n)119 void ff_acelp_apply_order_2_transfer_function(float *out, const float *in,
120 const float zero_coeffs[2],
121 const float pole_coeffs[2],
122 float gain, float mem[2], int n)
123 {
124 int i;
125 float tmp;
126
127 for (i = 0; i < n; i++) {
128 tmp = gain * in[i] - pole_coeffs[0] * mem[0] - pole_coeffs[1] * mem[1];
129 out[i] = tmp + zero_coeffs[0] * mem[0] + zero_coeffs[1] * mem[1];
130
131 mem[1] = mem[0];
132 mem[0] = tmp;
133 }
134 }
135
ff_tilt_compensation(float * mem,float tilt,float * samples,int size)136 void ff_tilt_compensation(float *mem, float tilt, float *samples, int size)
137 {
138 float new_tilt_mem = samples[size - 1];
139 int i;
140
141 for (i = size - 1; i > 0; i--)
142 samples[i] -= tilt * samples[i - 1];
143
144 samples[0] -= tilt * *mem;
145 *mem = new_tilt_mem;
146 }
147
ff_acelp_filter_init(ACELPFContext * c)148 void ff_acelp_filter_init(ACELPFContext *c)
149 {
150 c->acelp_interpolatef = ff_acelp_interpolatef;
151 c->acelp_apply_order_2_transfer_function = ff_acelp_apply_order_2_transfer_function;
152
153 if(HAVE_MIPSFPU)
154 ff_acelp_filter_init_mips(c);
155 }
156