[Kwintv] some problems with kdetv 0.83 and saa7134

[Hans-Peter Jansen]

On Tuesday 05 October 2004 07:53, Dirk Ziegelmeier wrote:
> On Monday 04 October 2004 22:57, Hans-Peter Jansen wrote:
> > Sorry for the wrong identifier, but the XVIDEO plugin is more
> > interesting for me, since it allows for scaled fullscreen
> > (without switching resolutions)..
>
> The v4l plugin can do that, too and is much more capable than the
> xvideo plugin (deinterlacing, overscan...). The configuration of
> you v4l plugin must be wrong. It should be as follows:
>
> - "Use overlay" should be disabled
> - Video output method: "XVideo" or "XVideo with SHM"
> - Depending on you CPU speed, "full frame rate"

Hmm, without overlay, I get a dialog: "Video display not possible..", 
(no video filters, no deinterlacing), and results in "black eagle on 
black background" but sound works.
Funny is, if I quit and restart kdetv, one or two frames _can_ be 
displayed, before this dialog appears. 

With overlay, the screen flickers horrible on channel switch, combined 
with horizontal distortions speckled in and outside the kdetv window.
Opening the config dialog is overlayed partly by video output. 

> > Dirk, could you point me to the method, where XVideo Scaling
> > happens?
>
> Nowhere ;-) It's done by the v4l bridge in the X-server. The only
> thing kdetv does is to tell the X-Server it should display video in
> a widget with the desired size (XPutVideo() in kvideoio/kxv.cpp).
> The v4l bridge then captures from the tv card into memory and uses
> the graphics card's hardware scaling to resize the image.
>
> BTW, the v4l plugin also uses hardware scaling, since the
> XvPutImage call is usually accelerated by the graphics card (in
> fact, that's why it exists). XvPutImage
> (kvideoio/qvideostream::displayImage()) converts an YUV image to
> RGB, resizes it and displays it in a widget.

This are very interesting informations, which will take a while before 
settling down in my brain ;-). Thanks

> > BTW: I noticed a mysterious Xv port 70 "Matrox G-Series Backend
> > Scaler", why cannot it be used?
>
> That's no video port, but an image port. It's used by the v4l
> plugin to scale the image.

Hopefully, we will get this to work soon. I will try to test kdetv on 
my hauppauge setup to see if it makes a difference (based on SuSE 
9.1.42 (B3) as used above)..

Pete