[Kdenlive-devel] Title Widget / Monitor scene speed

[Till Theato]

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>>>>>>
>>>>>>> I guess what you mean is that e.g. moving objects has a delay of around 0.2 s?
>>>>>>>
> 
>> For me the delay is much longer 0.2 s. Maybe around 1s.
>>>>
>>>> I seem to recall some interesting blog posts on the Nokia Qt site
>>>> about QGraphicsScene performance.
> 
> Could not find anything that results in a noticeable improvement, but
> while testing I figured out that the speed depends on the size. Not the
> size of the scene but of the view. So the smaller the monitor, the
> better/faster editing geometries works.
> I still have no idea what causes this behavior.

So I finally found out what was responsible for the slowness.
In some posts it was recommended to use a QGLWidget as the viewport for
QGraphicsView. After doing so the speed was amazingly, however there
were a lot of crashes in nouveou (open source driver for nvidia cards)
therefore I switched back (after half a year, see OP ;) ) to the nvidia
one. Now also without using a QGLWidget I can work fluently with
on-monitor effects.
So maybe I will have a look at the QGLWidget thing again after 0.7.8 is
released.

Btw. during playback the background frame is only updated every 200 ms
because updating it every time a frameUpdated signal is received will
cause the GUI to not respond anymore. But this should not be a problem
as there is a button to switch to the normal monitor for preview purposes.

regards till
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