[mythtv] [mythtv-commits] Ticket #7525: Optimize Pulse handling in MythUI

Stuart Morgan stuart at tase.co.uk
Sat Aug 28 17:04:05 UTC 2010


On Friday 27 Aug 2010 03:17:34 Michael T. Dean wrote:
>   On 08/26/2010 06:17 PM, Gavin Hurlbut wrote:
> > I'm not sure how 70Hz was ever decided on
> 
> For the actual animations stuff (the screen refreshes, but not
> necessarily the alphapulse), IIRC, 70Hz was chosen because of the 60Hz
> beat of the seconds display in the clock--we needed some value >60Hz to
> ensure we didn't skip any seconds.  Stuart M. could probably give a lot
> more detail when he returns.

I'm not the guy to ask about the choice of 70Hz, that was inherited from the 
original bones of mythui before I got my hands on it. Isaac chose the figure 
and although I did discuss it with him a couple of years ago I really don't 
remember the reasons given.

Daniel has neatly explained why it would be more efficient for effects to be 
time-based but also why a precise time-based method isn't what we want either. 
We'd want a compromise where we don't drop frames, we don't actually need to 
do so since we're not worried about synchronisation*. We could treat times as 
as "best effort" target and adjust future times to a maintain the correct 
frame interval, so animations may run slowly but you'll avoid a see-saw with 
it then running very fast to compensate.
-- 
Stuart Morgan


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