0eec06ed87
These functions are using the POSIX clock_gettime() function with the CLOCK_MONOTONIC clock id. If these are not present on the targeted platform, the new functions will fallback on using the original realtime functions av_gettime() and av_usleep(). Monotonic support can be added on other platforms with their equivalent native system API eventually if possible. Whenever time is requested to measure relative time, the monotonic clock, when available, is superior to the system realtime clock because it is not affected by discontinuous jumps in the system time In a future step, offering the flexibility to let the user choose between rt and monotonic clock for avdevices packets will be investigated. It is very easy to experience the issues that this patch attempt to address by rewinding back in the past the system time while ffmpeg is running. this is breaking the ffmpeg report printing (ffmepg.c:print_report()) and the the rate emulator functionality (-re) without the patch. Signed-off-by: Olivier Langlois <olivier@trillion01.com> Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
57 lines
1.8 KiB
C
57 lines
1.8 KiB
C
/*
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* Copyright (c) 2000-2003 Fabrice Bellard
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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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#ifndef AVUTIL_TIME_H
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#define AVUTIL_TIME_H
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#include <stdint.h>
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/**
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* Get the current time in microseconds.
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*/
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int64_t av_gettime(void);
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/**
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* Get the current time in microseconds since some unspecified starting point.
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* On platforms that support it, the time comes from a monotonic clock
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* This property makes this time source ideal for measuring relative time.
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* If a monotonic clock is not available on the targeted platform, the
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* implementation fallsback on using av_gettime().
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*/
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int64_t av_gettime_relative(void);
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/**
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* Indicates with a boolean result if the av_gettime_relative() time source
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* is monotonic.
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*/
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int av_gettime_relative_is_monotonic(void);
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/**
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* Sleep for a period of time. Although the duration is expressed in
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* microseconds, the actual delay may be rounded to the precision of the
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* system timer.
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*
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* @param usec Number of microseconds to sleep.
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* @return zero on success or (negative) error code.
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*/
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int av_usleep(unsigned usec);
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#endif /* AVUTIL_TIME_H */
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