blob: 35aa863e7a1a5cd3a9a73c6bcedf325bf3681c70
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 | |
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 | |
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 | |
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 | |
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 | |
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 | |
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 |