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