| 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 cliping 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 | } |