[FFmpeg-devel] [PATCH] Use monotonic clock formeasuring reltime.

[Don Moir]

>> > Can change during daylight savings time switch over by an hour as well.
>>
>> Wrong.

>It depends. You have the option to store the system time in the RTC (hardware clock) either as UTC or local time in Linux. Setting 
>RTC time in local time isn't advised but >may be required if dual booting with Windows. When having DST change, you either let the 
>other OS  correct the RTC time or you can manually fix it.

>I have 0 Windows installation around me so I am not sure but I would not totally rule out that manual DST management can have 
>effect on system time.

>inspect /etc/adjtime content to find out how your RTC is configured or see

>http://tldp.org/HOWTO/Clock-2.html

>for more info on the topic.

For windows, I went thru the RTC route, timeGetTime, QueryPerformanceCounter, and GetSystemTimeAsFileTime. Each one has some degree 
of problem.

For my own timing I use QueryPerformanceCounter. Even though it may have had issues in the past, it does not fail and very accurate.

timeGetTime is accurate but needs setup (as does QueryPerformanceCounter) and you also need to watch for wrap and requires link to 
winmm.dll.

Since timing can vary so much, I suggest again to allow a user settable timer function.