dbc223eb84
Import existing source tree; original VCS history is no longer available. 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude <noreply@anthropic.com>
111 lines
3.6 KiB
C
111 lines
3.6 KiB
C
/*(LGPL)
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---------------------------------------------------------------------------
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a_filters.h - Various Audio Signal Filters
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---------------------------------------------------------------------------
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* Copyright (C) 2001, 2002, David Olofson
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU Lesser General Public License as published by
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* the Free Software Foundation; either version 2.1 of the License, or (at
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* your option) any later version.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public License
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* along with this program; if not, write to the Free Software Foundation,
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* Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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#ifndef _A_FILTERS_H_
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#define _A_FILTERS_H_
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/*--------------------------------------------------------------------
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f6_t - Simple mono 6 dB/oct state variable filter
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--------------------------------------------------------------------*/
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typedef struct f6_t
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{
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int rate;
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int d;
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int f;
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} f6_t;
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void f6_init(f6_t *fil, int fs);
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void f6_set_f(f6_t *fil, int f);
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void f6_process_lp(f6_t *fil, int *buf, unsigned frames);
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void f6_process_hp(f6_t *fil, int *buf, unsigned frames);
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/*--------------------------------------------------------------------
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f6s_t - Simple stereo 6 dB/oct state variable filter
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--------------------------------------------------------------------*/
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typedef struct f6s_t
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{
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int rate;
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int f;
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int dl, dr;
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} f6s_t;
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void f6s_init(f6s_t *fil, int fs);
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void f6s_set_f(f6s_t *fil, int f);
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void f6s_process_lp(f6s_t *fil, int *buf, unsigned frames);
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void f6s_process_hp(f6s_t *fil, int *buf, unsigned frames);
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/*--------------------------------------------------------------------
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dcf6s_t - Fast stereo 6 dB/oct HPF for DC suppression
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--------------------------------------------------------------------*/
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typedef struct dcf6s_t
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{
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int rate;
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int f;
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int dl, dr;
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} dcf6s_t;
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void dcf6s_init(dcf6s_t *fil, int fs);
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void dcf6s_set_f(dcf6s_t *fil, int f);
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void dcf6s_process(dcf6s_t *fil, int *buf, unsigned frames);
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int dcf6s_silent(dcf6s_t *fil);
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/*--------------------------------------------------------------------
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resof12_t - Resonant mono 12 dB/oct state variable filter
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--------------------------------------------------------------------*/
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typedef struct resof12_t
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{
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int rate;
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int d1, d2;
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int f;
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int q;
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} resof12_t;
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void resof12_init(resof12_t *rf, int fs);
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void resof12_set_f(resof12_t *rf, int f);
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void resof12_set_q(resof12_t *rf, int q);
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void resof12_process_lp(resof12_t *rf, int *buf, unsigned frames); /*In-place LP*/
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void resof12_process_hp(resof12_t *rf, int *buf, unsigned frames); /*In-place HP*/
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void resof12_process_bp(resof12_t *rf, int *buf, unsigned frames); /*In-place BP*/
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/*
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* LP filter the 'buf' buffer, while separating off
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* the HP part into buffer 'out'.
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*/
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void resof12_process_split(resof12_t *rf, int *buf, int *out, unsigned frames);
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/*--------------------------------------------------------------------
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resof12s_t - Resonant stereo 12 dB/oct state variable filter
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--------------------------------------------------------------------*/
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typedef struct resof12s_t
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{
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int rate;
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int d1l, d2l;
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int d1r, d2r;
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int f;
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int q;
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} resof12s_t;
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void resof12s_init(resof12s_t *rf, int fs);
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void resof12s_set_f(resof12s_t *rf, int f);
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void resof12s_set_q(resof12s_t *rf, int q);
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void resof12s_process_lp(resof12s_t *rf, int *buf, unsigned frames); /*In-place LP*/
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#endif /*_A_FILTERS_H_*/
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