libaf/filter.h

   1 /*=============================================================================
   2 //
   3 //  This software has been released under the terms of the GNU General Public
   4 //  license. See http://www.gnu.org/copyleft/gpl.html for details.
   5 //
   6 //  Copyright 2001 Anders Johansson ajh@atri.curtin.edu.au
   7 //
   8 //=============================================================================
   9 */
  10
  11 #if !defined MPLAYER_DSP_H
  12 # error Never use filter.h directly; include dsp.h instead.
  13 #endif
  14
  15 #ifndef MPLAYER_FILTER_H
  16 #define MPLAYER_FILTER_H
  17
  18
  19 // Design and implementation of different types of digital filters
  20
  21
  22 // Flags used for filter design
  23
  24 // Filter characteristics
  25 #define LP          0x00010000 // Low pass
  26 #define HP          0x00020000 // High pass
  27 #define BP          0x00040000 // Band pass
  28 #define BS          0x00080000 // Band stop
  29 #define TYPE_MASK   0x000F0000
  30
  31 // Window types
  32 #define BOXCAR      0x00000001
  33 #define TRIANG      0x00000002
  34 #define HAMMING     0x00000004
  35 #define HANNING     0x00000008
  36 #define BLACKMAN    0x00000010
  37 #define FLATTOP     0x00000011
  38 #define KAISER      0x00000012
  39 #define WINDOW_MASK 0x0000001F
  40
  41 // Parallel filter design
  42 #define FWD         0x00000001 // Forward indexing of polyphase filter
  43 #define REW         0x00000002 // Reverse indexing of polyphase filter
  44 #define ODD         0x00000010 // Make filter HP
  45
  46 // Exported functions
  47 FLOAT_TYPE af_filter_fir(unsigned int n, const FLOAT_TYPE* w, const FLOAT_TYPE* x);
  48
  49 FLOAT_TYPE* af_filter_pfir(unsigned int n, unsigned int k,
  50                            unsigned int xi, const FLOAT_TYPE** w,
  51                            const FLOAT_TYPE** x, FLOAT_TYPE* y,
  52                            unsigned int s);
  53
  54 //int af_filter_updateq(unsigned int n, unsigned int xi,
  55 //                      FLOAT_TYPE* xq, FLOAT_TYPE* in);
  56 int af_filter_updatepq(unsigned int n, unsigned int k, unsigned int xi,
  57                        FLOAT_TYPE** xq, const FLOAT_TYPE* in, unsigned int s);
  58
  59 int af_filter_design_fir(unsigned int n, FLOAT_TYPE* w, const FLOAT_TYPE* fc,
  60                          unsigned int flags, FLOAT_TYPE opt);
  61
  62 int af_filter_design_pfir(unsigned int n, unsigned int k, const FLOAT_TYPE* w,
  63                           FLOAT_TYPE** pw, FLOAT_TYPE g, unsigned int flags);
  64
  65 int af_filter_szxform(const FLOAT_TYPE* a, const FLOAT_TYPE* b, FLOAT_TYPE Q,
  66                       FLOAT_TYPE fc, FLOAT_TYPE fs, FLOAT_TYPE *k,
  67                       FLOAT_TYPE *coef);
  68
  69 /* Add new data to circular queue designed to be used with a FIR
  70    filter. xq is the circular queue, in pointing at the new sample, xi
  71    current index for xq and n the length of the filter. xq must be n*2
  72    long.
  73 */
  74 #define af_filter_updateq(n,xi,xq,in)\
  75   xq[xi]=(xq)[(xi)+(n)]=*(in);\
  76   xi=(++(xi))&((n)-1);
  77
  78 #endif /* MPLAYER_FILTER_H */