libavcodec/dcadsp.c

   1 /*
   2  * Copyright (c) 2004 Gildas Bazin
   3  * Copyright (c) 2010 Mans Rullgard <mans@mansr.com>
   4  *
   5  * This file is part of Libav.
   6  *
   7  * Libav is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU Lesser General Public
   9  * License as published by the Free Software Foundation; either
  10  * version 2.1 of the License, or (at your option) any later version.
  11  *
  12  * Libav is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * Lesser General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Lesser General Public
  18  * License along with Libav; if not, write to the Free Software
  19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  20  */
  21
  22 #include "config.h"
  23 #include "dcadsp.h"
  24
  25 static void dca_lfe_fir_c(float *out, const float *in, const float *coefs,
  26                           int decifactor, float scale)
  27 {
  28     float *out2 = out + decifactor;
  29     const float *cf0 = coefs;
  30     const float *cf1 = coefs + 256;
  31     int j, k;
  32
  33     /* One decimated sample generates 2*decifactor interpolated ones */
  34     for (k = 0; k < decifactor; k++) {
  35         float v0 = 0.0;
  36         float v1 = 0.0;
  37         for (j = 0; j < 256 / decifactor; j++) {
  38             float s = in[-j];
  39             v0 += s * *cf0++;
  40             v1 += s * *--cf1;
  41         }
  42         *out++  = v0 * scale;
  43         *out2++ = v1 * scale;
  44     }
  45 }
  46
  47 void ff_dcadsp_init(DCADSPContext *s)
  48 {
  49     s->lfe_fir = dca_lfe_fir_c;
  50     if (ARCH_ARM) ff_dcadsp_init_arm(s);
  51 }