libavcodec/mlpdsp.c

   1 /*
   2  * Copyright (c) 2007-2008 Ian Caulfield
   3  *               2009 Ramiro Polla
   4  *
   5  * This file is part of FFmpeg.
   6  *
   7  * FFmpeg 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  * FFmpeg 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 FFmpeg; if not, write to the Free Software
  19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  20  */
  21
  22 #include "dsputil.h"
  23
  24 static void ff_mlp_filter_channel(int32_t *firbuf, const int32_t *fircoeff, int firorder,
  25                                   int32_t *iirbuf, const int32_t *iircoeff, int iirorder,
  26                                   unsigned int filter_shift, int32_t mask, int blocksize,
  27                                   int32_t *sample_buffer)
  28 {
  29     int i;
  30
  31     for (i = 0; i < blocksize; i++) {
  32         int32_t residual = *sample_buffer;
  33         unsigned int order;
  34         int64_t accum = 0;
  35         int32_t result;
  36
  37         for (order = 0; order < firorder; order++)
  38             accum += (int64_t) firbuf[order] * fircoeff[order];
  39         for (order = 0; order < iirorder; order++)
  40             accum += (int64_t) iirbuf[order] * iircoeff[order];
  41
  42         accum  = accum >> filter_shift;
  43         result = (accum + residual) & mask;
  44
  45         *--firbuf = result;
  46         *--iirbuf = result - accum;
  47
  48         *sample_buffer = result;
  49         sample_buffer += 8;
  50     }
  51 }
  52
  53 void ff_mlp_init(DSPContext* c, AVCodecContext *avctx)
  54 {
  55     c->mlp_filter_channel = ff_mlp_filter_channel;
  56 }