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

[Daniel Kristjansson]

On Thu, 2010-08-26 at 15:17 -0700, Gavin Hurlbut wrote:
> On Thu, Aug 26, 2010 at 3:05 PM, Jim Stichnoth <stichnot at gmail.com> 

> I would suggest that we change the pulsing (assuming this is even
> technically possible) to happen at 24fps at the fastest (film rate). 
> Or am I missing something here?

Two things:

First, a refresh of 24fps would look terrible on a 1080i display.*
You want the animation refresh rate to be an integer mul/div 
of the display refresh rate. For a 1080i display 14.99 fps
would probably be fine and 29.97 fps would be nice. 70 fps is
not an integer mul/div of any common TV display which makes 
it not so great for animations, but when you don't match the
display refresh rate, then the higher the better.

Second, the existing animations are hard coded to a 70fps refresh.
If you lower the tick they run slower, If you increase it they run
faster.

It's the second problem which is a bigger problem. If someone went
through the code and fixed them to be time based it would be easy
to run the animation at say half the refresh rate i.e. 29.97fps
when there had been recent frontend activity. Then ratchet down to
half that after a while. This is not always trivial. Imagine a
bouncing rubber ball, if you take out the frame where it hits the
floor when dropping from 29.97 to 14.99 fps then it will look 
very odd as it never hits the ground and never deforms as you
expect a rubber ball to do.

-- Daniel

*TV uses 3:2 pulldown and slows down the movie to 23.98 fps to
allow 24fps movies to work with NTSC rates. Applying pulldown
would use much more CPU..