iirfilter.h

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/*
 * IIR filter
 * Copyright (c) 2008 Konstantin Shishkov
 *
 * This file is part of FFmpeg.
 *
 * FFmpeg is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * FFmpeg is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with FFmpeg; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

#ifndef AVCODEC_IIRFILTER_H
#define AVCODEC_IIRFILTER_H

#include <stddef.h>
#include <stdint.h>

struct FFIIRFilterCoeffs;
struct FFIIRFilterState;

enum IIRFilterType{
    FF_FILTER_TYPE_BESSEL,
    FF_FILTER_TYPE_BIQUAD,
    FF_FILTER_TYPE_BUTTERWORTH,
    FF_FILTER_TYPE_CHEBYSHEV,
    FF_FILTER_TYPE_ELLIPTIC,
};

enum IIRFilterMode{
    FF_FILTER_MODE_LOWPASS,
    FF_FILTER_MODE_HIGHPASS,
    FF_FILTER_MODE_BANDPASS,
    FF_FILTER_MODE_BANDSTOP,
};

typedef struct FFIIRFilterContext {
    void (*filter_flt)(const struct FFIIRFilterCoeffs *coeffs,
                        struct FFIIRFilterState *state, int size,
                        const float *src, ptrdiff_t sstep, float *dst, ptrdiff_t dstep);
} FFIIRFilterContext;

void ff_iir_filter_init(FFIIRFilterContext *f);
void ff_iir_filter_init_mips(FFIIRFilterContext *f);

struct FFIIRFilterCoeffs* ff_iir_filter_init_coeffs(void *avc,
                                                enum IIRFilterType filt_type,
                                                enum IIRFilterMode filt_mode,
                                                int order, float cutoff_ratio,
                                                float stopband, float ripple);

struct FFIIRFilterState* ff_iir_filter_init_state(int order);

void ff_iir_filter_free_coeffsp(struct FFIIRFilterCoeffs **coeffs);

void ff_iir_filter_free_statep(struct FFIIRFilterState **state);

void ff_iir_filter(const struct FFIIRFilterCoeffs *coeffs, struct FFIIRFilterState *state,
                   int size, const int16_t *src, ptrdiff_t sstep, int16_t *dst, ptrdiff_t dstep);

void ff_iir_filter_flt(const struct FFIIRFilterCoeffs *coeffs,
                       struct FFIIRFilterState *state, int size,
                       const float *src, ptrdiff_t sstep,
                       float *dst, ptrdiff_t dstep);

#endif /* AVCODEC_IIRFILTER_H */