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Diffstat (limited to 'libavformat/timefilter.h')
-rw-r--r-- | libavformat/timefilter.h | 97 |
1 files changed, 0 insertions, 97 deletions
diff --git a/libavformat/timefilter.h b/libavformat/timefilter.h deleted file mode 100644 index aa7db533b4..0000000000 --- a/libavformat/timefilter.h +++ /dev/null @@ -1,97 +0,0 @@ -/* - * Delay Locked Loop based time filter prototypes and declarations - * 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 - */ - -#ifndef AVFORMAT_TIMEFILTER_H -#define AVFORMAT_TIMEFILTER_H - -/** - * Opaque type representing a time filter state - * - * The purpose of this filter is to provide a way to compute accurate time - * stamps that can be compared to wall clock time, especially when dealing - * with two clocks: the system clock and a hardware device clock, such as - * a soundcard. - */ -typedef struct TimeFilter TimeFilter; - - -/** - * Create a new Delay Locked Loop time filter - * - * feedback2_factor and feedback3_factor are the factors used for the - * multiplications that are respectively performed in the second and third - * feedback paths of the loop. - * - * Unless you know what you are doing, you should set these as follow: - * - * o = 2 * M_PI * bandwidth * period - * feedback2_factor = sqrt(2 * o) - * feedback3_factor = o * o - * - * Where bandwidth is up to you to choose. Smaller values will filter out more - * of the jitter, but also take a longer time for the loop to settle. A good - * starting point is something between 0.3 and 3 Hz. - * - * @param clock_period period of the hardware clock in seconds - * (for example 1.0/44100) - * - * For more details about these parameters and background concepts please see: - * http://www.kokkinizita.net/papers/usingdll.pdf - */ -TimeFilter * ff_timefilter_new(double clock_period, double feedback2_factor, double feedback3_factor); - -/** - * Update the filter - * - * This function must be called in real time, at each process cycle. - * - * @param period the device cycle duration in clock_periods. For example, at - * 44.1kHz and a buffer size of 512 frames, period = 512 when clock_period - * was 1.0/44100, or 512/44100 if clock_period was 1. - * - * system_time, in seconds, should be the value of the system clock time, - * at (or as close as possible to) the moment the device hardware interrupt - * occured (or any other event the device clock raises at the beginning of a - * cycle). - * - * @return the filtered time, in seconds - */ -double ff_timefilter_update(TimeFilter *self, double system_time, double period); - -/** - * Reset the filter - * - * This function should mainly be called in case of XRUN. - * - * Warning: after calling this, the filter is in an undetermined state until - * the next call to ff_timefilter_update() - */ -void ff_timefilter_reset(TimeFilter *); - -/** - * Free all resources associated with the filter - */ -void ff_timefilter_destroy(TimeFilter *); - -#endif /* AVFORMAT_TIMEFILTER_H */ |