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/* |
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* This file is part of FFmpeg. |
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* |
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* FFmpeg is free software; you can redistribute it and/or |
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* modify it under the terms of the GNU Lesser General Public |
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* License as published by the Free Software Foundation; either |
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* version 2.1 of the License, or (at your option) any later version. |
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* |
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* FFmpeg is distributed in the hope that it will be useful, |
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* but 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 |
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* License along with FFmpeg; if not, write to the Free Software |
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
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*/ |
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#include <math.h> |
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#include <stdint.h> |
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#include <stdio.h> |
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#include "libavutil/libm.h" |
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#include "libavcodec/iirfilter.h" |
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#define FILT_ORDER 4 |
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#define SIZE 1024 |
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int main(void) |
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{ |
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struct FFIIRFilterCoeffs *fcoeffs = NULL; |
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struct FFIIRFilterState *fstate = NULL; |
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float cutoff_coeff = 0.4; |
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int16_t x[SIZE], y[SIZE]; |
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int i; |
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fcoeffs = ff_iir_filter_init_coeffs(NULL, FF_FILTER_TYPE_BUTTERWORTH, |
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FF_FILTER_MODE_LOWPASS, FILT_ORDER, |
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cutoff_coeff, 0.0, 0.0); |
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fstate = ff_iir_filter_init_state(FILT_ORDER); |
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✓✓ |
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for (i = 0; i < SIZE; i++) |
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x[i] = lrint(0.75 * INT16_MAX * sin(0.5 * M_PI * i * i / SIZE)); |
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ff_iir_filter(fcoeffs, fstate, SIZE, x, 1, y, 1); |
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✓✓ |
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for (i = 0; i < SIZE; i++) |
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printf("%6d %6d\n", x[i], y[i]); |
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ff_iir_filter_free_coeffsp(&fcoeffs); |
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ff_iir_filter_free_statep(&fstate); |
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return 0; |
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} |