mirror of https://github.com/mpv-player/mpv
66 lines
2.2 KiB
C
66 lines
2.2 KiB
C
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/*=============================================================================
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//
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// This software has been released under the terms of the GNU Public
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// license. See http://www.gnu.org/copyleft/gpl.html for details.
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//
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// Copyright 2001 Anders Johansson ajh@atri.curtin.edu.au
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//
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//=============================================================================
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*/
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#if !defined _DSP_H
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# error "Never use <filter.h> directly; include <dsp.h> instead"
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#endif
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#ifndef _FILTER_H
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#define _FILTER_H 1
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// Design and implementation of different types of digital filters
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// Flags used for filter design
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// Filter characteristics
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#define LP 0x00010000 // Low pass
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#define HP 0x00020000 // High pass
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#define BP 0x00040000 // Band pass
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#define BS 0x00080000 // Band stop
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#define TYPE_MASK 0x000F0000
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// Window types
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#define BOXCAR 0x00000001
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#define TRIANG 0x00000002
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#define HAMMING 0x00000004
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#define HANNING 0x00000008
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#define BLACKMAN 0x00000010
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#define FLATTOP 0x00000011
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#define KAISER 0x00000012
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#define WINDOW_MASK 0x0000001F
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// Parallel filter design
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#define FWD 0x00000001 // Forward indexing of polyphase filter
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#define REW 0x00000002 // Reverse indexing of polyphase filter
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#define ODD 0x00000010 // Make filter HP
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// Exported functions
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extern _ftype_t fir(unsigned int n, _ftype_t* w, _ftype_t* x);
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extern _ftype_t* pfir(unsigned int n, unsigned int k, unsigned int xi, _ftype_t** w, _ftype_t** x, _ftype_t* y, unsigned int s);
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extern int updateq(unsigned int n, unsigned int xi, _ftype_t* xq, _ftype_t* in);
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extern int updatepq(unsigned int n, unsigned int k, unsigned int xi, _ftype_t** xq, _ftype_t* in, unsigned int s);
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extern int design_fir(unsigned int n, _ftype_t* w, _ftype_t* fc, unsigned int flags, _ftype_t opt);
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extern int design_pfir(unsigned int n, unsigned int k, _ftype_t* w, _ftype_t** pw, _ftype_t g, unsigned int flags);
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/* Add new data to circular queue designed to be used with a FIR
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filter. xq is the circular queue, in pointing at the new sample, xi
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current index for xq and n the length of the filter. xq must be n*2
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long.
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*/
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#define updateq(n,xi,xq,in)\
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xq[xi]=xq[xi+n]=*in;\
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xi=(++xi)&(n-1);
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#endif
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