release/src/router/ffmpeg/libavcodec/celp_filters.c

   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
  28 void ff_celp_convolve_circ(int16_t* fc_out, const int16_t* fc_in,
  29                            const int16_t* filter, int len)
  30 {
  31     int i, k;
  32
  33     memset(fc_out, 0, len * sizeof(int16_t));
  34
  35     /* Since there are few pulses over an entire subframe (i.e. almost
  36        all fc_in[i] are zero) it is faster to loop over fc_in first. */
  37     for (i = 0; i < len; i++) {
  38         if (fc_in[i]) {
  39             for (k = 0; k < i; k++)
  40                 fc_out[k] += (fc_in[i] * filter[len + k - i]) >> 15;
  41
  42             for (k = i; k < len; k++)
  43                 fc_out[k] += (fc_in[i] * filter[      k - i]) >> 15;
  44         }
  45     }
  46 }
  47
  48 void ff_celp_circ_addf(float *out, const float *in,
  49                        const float *lagged, int lag, float fac, int n)
  50 {
  51     int k;
  52     for (k = 0; k < lag; k++)
  53         out[k] = in[k] + fac * lagged[n + k - lag];
  54     for (; k < n; k++)
  55         out[k] = in[k] + fac * lagged[    k - lag];
  56 }
  57
  58 int ff_celp_lp_synthesis_filter(int16_t *out, const int16_t *filter_coeffs,
  59                                 const int16_t *in, int buffer_length,
  60                                 int filter_length, int stop_on_overflow,
  61                                 int rounder)
  62 {
  63     int i,n;
  64
  65     for (n = 0; n < buffer_length; n++) {
  66         int sum = rounder;
  67         for (i = 1; i <= filter_length; i++)
  68             sum -= filter_coeffs[i-1] * out[n-i];
  69
  70         sum = (sum >> 12) + in[n];
  71
  72         if (sum + 0x8000 > 0xFFFFU) {
  73             if (stop_on_overflow)
  74                 return 1;
  75             sum = (sum >> 31) ^ 32767;
  76         }
  77         out[n] = sum;
  78     }
  79
  80     return 0;
  81 }
  82
  83 void ff_celp_lp_synthesis_filterf(float *out, const float *filter_coeffs,
  84                                   const float* in, int buffer_length,
  85                                   int filter_length)
  86 {
  87     int i,n;
  88
  89 #if 0 // Unoptimized code path for improved readability
  90     for (n = 0; n < buffer_length; n++) {
  91         out[n] = in[n];
  92         for (i = 1; i <= filter_length; i++)
  93             out[n] -= filter_coeffs[i-1] * out[n-i];
  94     }
  95 #else
  96     float out0, out1, out2, out3;
  97     float old_out0, old_out1, old_out2, old_out3;
  98     float a,b,c;
  99
 100     a = filter_coeffs[0];
 101     b = filter_coeffs[1];
 102     c = filter_coeffs[2];
 103     b -= filter_coeffs[0] * filter_coeffs[0];
 104     c -= filter_coeffs[1] * filter_coeffs[0];
 105     c -= filter_coeffs[0] * b;
 106
 107     old_out0 = out[-4];
 108     old_out1 = out[-3];
 109     old_out2 = out[-2];
 110     old_out3 = out[-1];
 111     for (n = 0; n <= buffer_length - 4; n+=4) {
 112         float tmp0,tmp1,tmp2,tmp3;
 113         float val;
 114
 115         out0 = in[0];
 116         out1 = in[1];
 117         out2 = in[2];
 118         out3 = in[3];
 119
 120         out0 -= filter_coeffs[2] * old_out1;
 121         out1 -= filter_coeffs[2] * old_out2;
 122         out2 -= filter_coeffs[2] * old_out3;
 123
 124         out0 -= filter_coeffs[1] * old_out2;
 125         out1 -= filter_coeffs[1] * old_out3;
 126
 127         out0 -= filter_coeffs[0] * old_out3;
 128
 129         val = filter_coeffs[3];
 130
 131         out0 -= val * old_out0;
 132         out1 -= val * old_out1;
 133         out2 -= val * old_out2;
 134         out3 -= val * old_out3;
 135
 136         old_out3 = out[-5];
 137
 138         for (i = 5; i <= filter_length; i += 2) {
 139             val = filter_coeffs[i-1];
 140
 141             out0 -= val * old_out3;
 142             out1 -= val * old_out0;
 143             out2 -= val * old_out1;
 144             out3 -= val * old_out2;
 145
 146             old_out2 = out[-i-1];
 147
 148             val = filter_coeffs[i];
 149
 150             out0 -= val * old_out2;
 151             out1 -= val * old_out3;
 152             out2 -= val * old_out0;
 153             out3 -= val * old_out1;
 154
 155             FFSWAP(float, old_out0, old_out2);
 156             old_out1 = old_out3;
 157             old_out3 = out[-i-2];
 158         }
 159
 160         tmp0 = out0;
 161         tmp1 = out1;
 162         tmp2 = out2;
 163         tmp3 = out3;
 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
 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 }