When targeting a recent enough macOS/iOS version that has clock_gettime
it won't be a weak symbol, in which case clang warns for this check
as it's always true:
warning: address of function 'clock_gettime' will always
evaluate to 'true'
This warning is silenced by using the address-of operator to make
the intent explicit.
Since av_gettime() is used in a number of places where actual
real time clock is required, the monotonic clock introduced in
ebef9f5a5 would have consequences that are hard to handle. Instead
split it into a separate function that can be used in the cases
where only relative time is desired.
On platform where no monotonic clock is available, the difference
between the two av_gettime functions is not clear, and one could
mistakenly use the relative clock where an absolute one is
required. Therefore add an offset, to make it evident that the
time returned from av_gettime_relative never is actual current
real time, even though it is based on av_gettime.
Based on a patch by Olivier Langlois.
Signed-off-by: Martin Storsjö <martin@martin.st>
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>
* qatar/master:
libspeexenc: add supported sample rates and channel layouts.
Replace usleep() calls with av_usleep()
lavu: add av_usleep() function
utvideo: mark interlaced frames as such
utvideo: Fix interlaced prediction for RGB utvideo.
cosmetics: do not use full path for local headers
lavu/file: include unistd.h only when available
configure: check for unistd.h
log: include unistd.h only when needed
lavf: include libavutil/time.h instead of redeclaring av_gettime()
Conflicts:
configure
doc/APIchanges
ffmpeg.c
ffplay.c
libavcodec/utvideo.c
libavutil/avutil.h
Merged-by: Michael Niedermayer <michaelni@gmx.at>
This function implements a delay using the first available
of the following functions:
- nanosleep()
- usleep()
- Sleep() (Windows)
The conditional #includes in time.c are simplified by including
unistd.h and windows.h whenever they are available rather than
having these lines triggered by specific functions.
Signed-off-by: Mans Rullgard <mans@mansr.com>
Libav.org has removed this while moving the code around
For reference, the code was originally added in:
commit 9aeeeb63f7
Author: Fabrice Bellard <fabrice@bellard.org>
Date: Wed Dec 20 00:02:47 2000 +0000
Initial revision
Originally committed as revision 2 to svn://svn.ffmpeg.org/ffmpeg/trunk
--
The function name originates from:
commit 9498853132
Author: Fabrice Bellard <fabrice@bellard.org>
Date: Thu Jul 25 16:01:46 2002 +0000
more consistent naming
Originally committed as revision 802 to svn://svn.ffmpeg.org/ffmpeg/trunk
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
