• Olivier Langlois's avatar
    lavu: add av_gettime_relative() · 0eec06ed
    Olivier Langlois authored
    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: 's avatarOlivier Langlois <olivier@trillion01.com>
    Signed-off-by: 's avatarMichael Niedermayer <michaelni@gmx.at>
    0eec06ed
APIchanges 75 KB