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