[Kwintv] Re: Heavy flickery and noise when switching viewmode in qtvision

[Dirk Ziegelmeier]

On Sunday 04 January 2004 15:16, Florian Evers wrote:
> But it's a great pity that I have a lot of interlace
> effects when I'm using the Video4Linux plugin!
You are right. Try the XVIDEO plugin, on my box, it deinterlaces. But this 
depends on the graphics card/graphics driver.

> Even though I activated
> "Video4Linux Plugin Configuration"
>   -> "Advanced"
>     -> "Prefer video overlay if possible"
> there are these interlace effects.
Yup, because it's _OVERLAY_ and not DEINTERLACE.

> Is there a possibility to
> a) Fix the flickery when using XVideo or
there surely is, but I only know how to reduce it, not how to eliminate it. It 
is caused by hiding/unhiding toolbars, menubars and dockwindows. Every action 
triggers a repaint. And because I was lazy, I only implemented transitions 
from Normal view mode to the others and back. So when I switch from 
fullscreen to tv, the real transition is fullscreen -> normal -> tv mode 
which causes excessive flicker. I did this because I did not want to 
implement every possible viewmode transistion. I'll try to optimize 
hiding/showing of the GUI elements, but this will not completely fix it. The 
best would be to disable GUI updates during the transition. I already tried 
QWidget::setUpdatesEnabled(), but it didn't do the trick.

> b) activate de-interlacing in Video4Linux?
Yes. Just let me set that deinterlace bit in the bttv driver... No, seriously, 
this means adding image filtering infrastructure and adapting/developing 
deinterlace filters, don't expect that to happen anywhere in the near future.

Dirk