d12b5b2f13
This avoids spurious library rebuilds when only the test program code is changed and simplifies the build system.
80 lines
2.4 KiB
C
80 lines
2.4 KiB
C
/*
|
|
* Delay Locked Loop based time filter
|
|
* Copyright (c) 2009 Samalyse
|
|
* Copyright (c) 2009 Michael Niedermayer
|
|
* Author: Olivier Guilyardi <olivier samalyse com>
|
|
* Michael Niedermayer <michaelni gmx at>
|
|
*
|
|
* This file is part of Libav.
|
|
*
|
|
* Libav 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.
|
|
*
|
|
* Libav 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 Libav; if not, write to the Free Software
|
|
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
|
|
*/
|
|
|
|
#include "libavutil/common.h"
|
|
#include "libavutil/mem.h"
|
|
|
|
#include "timefilter.h"
|
|
|
|
struct TimeFilter {
|
|
// Delay Locked Loop data. These variables refer to mathematical
|
|
// concepts described in: http://www.kokkinizita.net/papers/usingdll.pdf
|
|
double cycle_time;
|
|
double feedback2_factor;
|
|
double feedback3_factor;
|
|
double clock_period;
|
|
int count;
|
|
};
|
|
|
|
TimeFilter *ff_timefilter_new(double clock_period,
|
|
double feedback2_factor,
|
|
double feedback3_factor)
|
|
{
|
|
TimeFilter *self = av_mallocz(sizeof(TimeFilter));
|
|
|
|
if (!self)
|
|
return NULL;
|
|
|
|
self->clock_period = clock_period;
|
|
self->feedback2_factor = feedback2_factor;
|
|
self->feedback3_factor = feedback3_factor;
|
|
return self;
|
|
}
|
|
|
|
void ff_timefilter_destroy(TimeFilter *self)
|
|
{
|
|
av_freep(&self);
|
|
}
|
|
|
|
void ff_timefilter_reset(TimeFilter *self)
|
|
{
|
|
self->count = 0;
|
|
}
|
|
|
|
double ff_timefilter_update(TimeFilter *self, double system_time, double period)
|
|
{
|
|
self->count++;
|
|
if (self->count == 1) {
|
|
self->cycle_time = system_time;
|
|
} else {
|
|
double loop_error;
|
|
self->cycle_time += self->clock_period * period;
|
|
loop_error = system_time - self->cycle_time;
|
|
|
|
self->cycle_time += FFMAX(self->feedback2_factor, 1.0 / self->count) * loop_error;
|
|
self->clock_period += self->feedback3_factor * loop_error / period;
|
|
}
|
|
return self->cycle_time;
|
|
}
|