libfaad2/pulse.c

   1 /*
   2 ** FAAD2 - Freeware Advanced Audio (AAC) Decoder including SBR decoding
   3 ** Copyright (C) 2003-2004 M. Bakker, Ahead Software AG, http://www.nero.com
   4 **
   5 ** This program is free software; you can redistribute it and/or modify
   6 ** it under the terms of the GNU General Public License as published by
   7 ** the Free Software Foundation; either version 2 of the License, or
   8 ** (at your option) any later version.
   9 **
  10 ** This program is distributed in the hope that it will be useful,
  11 ** but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 ** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13 ** GNU General Public License for more details.
  14 **
  15 ** You should have received a copy of the GNU General Public License
  16 ** along with this program; if not, write to the Free Software
  17 ** Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  18 **
  19 ** Any non-GPL usage of this software or parts of this software is strictly
  20 ** forbidden.
  21 **
  22 ** Commercial non-GPL licensing of this software is possible.
  23 ** For more info contact Ahead Software through Mpeg4AAClicense@nero.com.
  24 **
  25 ** $Id: pulse.c,v 1.17 2004/09/04 14:56:28 menno Exp $
  26 **/
  27
  28 #include "common.h"
  29 #include "structs.h"
  30
  31 #include "syntax.h"
  32 #include "pulse.h"
  33
  34 uint8_t pulse_decode(ic_stream *ics, int16_t *spec_data, uint16_t framelen)
  35 {
  36     uint8_t i;
  37     uint16_t k;
  38     pulse_info *pul = &(ics->pul);
  39
  40     k = ics->swb_offset[pul->pulse_start_sfb];
  41
  42     for (i = 0; i <= pul->number_pulse; i++)
  43     {
  44         k += pul->pulse_offset[i];
  45
  46         if (k >= framelen)
  47             return 15; /* should not be possible */
  48
  49         if (spec_data[k] > 0)
  50             spec_data[k] += pul->pulse_amp[i];
  51         else
  52             spec_data[k] -= pul->pulse_amp[i];
  53     }
  54
  55     return 0;
  56 }