[FFmpeg-devel] [PATCH] Use monotonic clock formeasuring reltime.
LANGLOIS Olivier PIS -EXT
olivier.pis.langlois at transport.alstom.com
Wed Apr 2 21:55:11 CEST 2014
> > For windows, I went thru the RTC route, timeGetTime,
> QueryPerformanceCounter, and GetSystemTimeAsFileTime. Each one has
> > 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
> I think a lot of you think in the way of command line apps. I don't. Probably
> does not make much sense to have a user settable timer
> for command line apps.
It kinda does. Today the time source function is selectable at compile time with the help of defines. On Linux there is not that much choices and the best available choice is picked but if in Windows there is and each have their pros/cons, then it could be nice to be able to choose at runtime either with cmdline switch or from the UI on top of ffmpeg.
That would control the time function implementation dynamically. What I am trying to propose is slightly different however.
Offer monotonic clock function beside the actual realtime clock function and
Categorize ffmpeg time usage:
1. To measure relative time interval (monotonic should be preferred in this category)
2. Need realtime
3. Make this configurable whenever it makes sense (Personally, I'm mostly interested in libavdevice input formats ts)
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