libaf/filter.h

   1 /*
   2  * Copyright (C) 2001 Anders Johansson ajh@atri.curtin.edu.au
   3  *
   4  * This file is part of MPlayer.
   5  *
   6  * MPlayer is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * MPlayer is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License along
  17  * with MPlayer; if not, write to the Free Software Foundation, Inc.,
  18  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  19  */
  20
  21 #if !defined MPLAYER_DSP_H
  22 # error Never use filter.h directly; include dsp.h instead.
  23 #endif
  24
  25 #ifndef MPLAYER_FILTER_H
  26 #define MPLAYER_FILTER_H
  27
  28
  29 // Design and implementation of different types of digital filters
  30
  31
  32 // Flags used for filter design
  33
  34 // Filter characteristics
  35 #define LP          0x00010000 // Low pass
  36 #define HP          0x00020000 // High pass
  37 #define BP          0x00040000 // Band pass
  38 #define BS          0x00080000 // Band stop
  39 #define TYPE_MASK   0x000F0000
  40
  41 // Window types
  42 #define BOXCAR      0x00000001
  43 #define TRIANG      0x00000002
  44 #define HAMMING     0x00000004
  45 #define HANNING     0x00000008
  46 #define BLACKMAN    0x00000010
  47 #define FLATTOP     0x00000011
  48 #define KAISER      0x00000012
  49 #define WINDOW_MASK 0x0000001F
  50
  51 // Parallel filter design
  52 #define FWD         0x00000001 // Forward indexing of polyphase filter
  53 #define REW         0x00000002 // Reverse indexing of polyphase filter
  54 #define ODD         0x00000010 // Make filter HP
  55
  56 // Exported functions
  57 FLOAT_TYPE af_filter_fir(unsigned int n, const FLOAT_TYPE* w, const FLOAT_TYPE* x);
  58
  59 FLOAT_TYPE* af_filter_pfir(unsigned int n, unsigned int k,
  60                            unsigned int xi, const FLOAT_TYPE** w,
  61                            const FLOAT_TYPE** x, FLOAT_TYPE* y,
  62                            unsigned int s);
  63
  64 //int af_filter_updateq(unsigned int n, unsigned int xi,
  65 //                      FLOAT_TYPE* xq, FLOAT_TYPE* in);
  66 int af_filter_updatepq(unsigned int n, unsigned int k, unsigned int xi,
  67                        FLOAT_TYPE** xq, const FLOAT_TYPE* in, unsigned int s);
  68
  69 int af_filter_design_fir(unsigned int n, FLOAT_TYPE* w, const FLOAT_TYPE* fc,
  70                          unsigned int flags, FLOAT_TYPE opt);
  71
  72 int af_filter_design_pfir(unsigned int n, unsigned int k, const FLOAT_TYPE* w,
  73                           FLOAT_TYPE** pw, FLOAT_TYPE g, unsigned int flags);
  74
  75 int af_filter_szxform(const FLOAT_TYPE* a, const FLOAT_TYPE* b, FLOAT_TYPE Q,
  76                       FLOAT_TYPE fc, FLOAT_TYPE fs, FLOAT_TYPE *k,
  77                       FLOAT_TYPE *coef);
  78
  79 /* Add new data to circular queue designed to be used with a FIR
  80    filter. xq is the circular queue, in pointing at the new sample, xi
  81    current index for xq and n the length of the filter. xq must be n*2
  82    long.
  83 */
  84 #define af_filter_updateq(n,xi,xq,in)\
  85   xq[xi]=(xq)[(xi)+(n)]=*(in);\
  86   xi=(++(xi))&((n)-1);
  87
  88 #endif /* MPLAYER_FILTER_H */