apps/eq.h

   1 /***************************************************************************
   2  *             __________               __   ___.
   3  *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
   4  *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
   5  *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
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   7  *                     \/            \/     \/    \/            \/
   8  * $Id$
   9  *
  10  * Copyright (C) 2006-2007 Thom Johansen
  11  *
  12  * This program is free software; you can redistribute it and/or
  13  * modify it under the terms of the GNU General Public License
  14  * as published by the Free Software Foundation; either version 2
  15  * of the License, or (at your option) any later version.
  16  *
  17  * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
  18  * KIND, either express or implied.
  19  *
  20  ****************************************************************************/
  21
  22 #ifndef _EQ_H
  23 #define _EQ_H
  24
  25 #include <inttypes.h>
  26
  27 /* These depend on the fixed point formats used by the different filter types
  28    and need to be changed when they change.
  29  */
  30 #define FILTER_BISHELF_SHIFT 5
  31 #define EQ_PEAK_SHIFT 4
  32 #define EQ_SHELF_SHIFT 6
  33
  34 struct eqfilter {
  35     int32_t coefs[5];        /* Order is b0, b1, b2, a1, a2 */
  36     int32_t history[2][4];
  37 };
  38
  39 void filter_shelf_coefs(unsigned long cutoff, long A, bool low, int32_t *c);
  40 void filter_bishelf_coefs(unsigned long cutoff_low, unsigned long cutoff_high,
  41                           long A_low, long A_high, long A, int32_t *c);
  42 void eq_pk_coefs(unsigned long cutoff, unsigned long Q, long db, int32_t *c);
  43 void eq_ls_coefs(unsigned long cutoff, unsigned long Q, long db, int32_t *c);
  44 void eq_hs_coefs(unsigned long cutoff, unsigned long Q, long db, int32_t *c);
  45 void eq_filter(int32_t **x, struct eqfilter *f, unsigned num,
  46                unsigned channels, unsigned shift);
  47
  48 #endif
  49