[FFmpeg-devel] [PATCH] Use monotonic clock for measuringreltime.

Reimar Döffinger Reimar.Doeffinger at gmx.de
Wed Apr 2 18:46:38 CEST 2014


On 02.04.2014, at 18:18, "Don Moir" <donmoir at comcast.net> wrote:
> Le tridi 13 germinal, an CCXXII, Don Moir a écrit :
>>> The wall time can change by a second or seconds forward or backward
>>> depending on automated clock updates and user setting.
> 
>> They are bogus settings. Modern operating systems can smooth the correction
>> over a period of time to update the clock by a small amount.
> 
> Reality is it happens.

As mentioned other things happen as well, for example the monotonic clock not being affected by these changes, which if they are corrections is not necessarily better.
Plus, I don't think you quite finished why it makes it unsuitable.
Even with those clock updates it doesn't make it worse than TS timestamps (though I admit being worse would be quite an achievement).
Though I wasn't really arguing against using it (at least optionally), my main point is I just think the underlying issues (if there are any) need to be fixed either way.

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

Because only the local time changes, not the system time.
Windows (though I think only old versions) demonstrate that you can have both the same, but it also demonstrates that it is a stupid idea that doesn't work properly even after adding hacks on top of hacks to make it somewhat work.


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