86 lines
3.2 KiB
C
86 lines
3.2 KiB
C
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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 <stdio.h>
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#include "libavutil/common.h"
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#include "libavutil/lfg.h"
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#include "libavdevice/timefilter.h"
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#define LFG_MAX ((1LL << 32) - 1)
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int main(void)
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{
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AVLFG prng;
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double n0, n1;
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#define SAMPLES 1000
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double ideal[SAMPLES];
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double samples[SAMPLES];
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double samplet[SAMPLES];
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for (n0 = 0; n0 < 40; n0 = 2 * n0 + 1) {
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for (n1 = 0; n1 < 10; n1 = 2 * n1 + 1) {
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double best_error = 1000000000;
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double bestpar0 = n0 ? 1 : 100000;
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double bestpar1 = 1;
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int better, i;
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av_lfg_init(&prng, 123);
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for (i = 0; i < SAMPLES; i++) {
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samplet[i] = 10 + i + (av_lfg_get(&prng) < LFG_MAX/2 ? 0 : 0.999);
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ideal[i] = samplet[i] + n1 * i / (1000);
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samples[i] = ideal[i] + n0 * (av_lfg_get(&prng) - LFG_MAX / 2) / (LFG_MAX * 10LL);
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if(i && samples[i]<samples[i-1])
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samples[i]=samples[i-1]+0.001;
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}
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do {
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double par0, par1;
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better = 0;
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for (par0 = bestpar0 * 0.8; par0 <= bestpar0 * 1.21; par0 += bestpar0 * 0.05) {
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for (par1 = bestpar1 * 0.8; par1 <= bestpar1 * 1.21; par1 += bestpar1 * 0.05) {
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double error = 0;
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TimeFilter *tf = ff_timefilter_new(1, par0, par1);
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if (!tf) {
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printf("Could not allocate memory for timefilter.\n");
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exit(1);
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}
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for (i = 0; i < SAMPLES; i++) {
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double filtered;
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filtered = ff_timefilter_update(tf, samples[i], i ? (samplet[i] - samplet[i-1]) : 1);
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if(filtered < 0 || filtered > 1000000000)
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printf("filter is unstable\n");
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error += (filtered - ideal[i]) * (filtered - ideal[i]);
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}
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ff_timefilter_destroy(tf);
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if (error < best_error) {
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best_error = error;
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bestpar0 = par0;
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bestpar1 = par1;
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better = 1;
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}
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}
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}
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} while (better);
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printf(" [%12f %11f %9f]", bestpar0, bestpar1, best_error);
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}
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printf("\n");
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}
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return 0;
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}
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