[mythtv-users] ATI Interlacing questions

[Dan McCarthy]

On 1/18/06, Brandon Stoll <mrmagoo at mrmagoo.org> wrote:
> On 1/18/06, Dan McCarthy <mccadan at gmail.com> wrote:
> > Hi,
> >
> > I have a couple of questions about interlaced output with an ATI card.
> > I am using an ATI 9200 with TV out with the ATI fglrx binary driver
> > and svn mythtv. I capture from a dvb-t card.
> > I am getting interlacing artifacts on the displayed video. These are
> > chunky lines to the left or right of the image during motion.
> >
> > I understand that the SDTV DVB signal is interlaced. Does this mean
> > that I would need to use software deinterlace when using the TV out,
> > or is this handled automatically by the card? Is the TV out just some
> > kind of mirror output of what is shown on a monitor or is it treated
> > completely differently by the card?
> >
> > Also, I have the screen resolution set to 800x600. Should I be setting
> > this to 576x720 for SDTV PAL with a modeline (if possible) to avoid
> > any issues with image scaling before it goes out the TV out?
> >
> > Thanks,
> > Dan
>
> Do you want interlaced output or deinterlaced output?  If the first,
> you can't with an ATI card.  Even the newer nvidia drivers are broke
> from what I understand.
>
> I think what you want is in the settings under Playback, on the first
> page at the top: there is a box to enable deinterlacing.  The
> different types vary on how much CPU% they use and how well they work.

I want to output to a SD PAL  television, which I would assume means
interlaced output. What I am having trouble getting my head around is
that the PAL format requires interlacing already, correct? Therefore
it would suggest that SDTV received interlaced from DVB should play
back fine on the 'interlaced PAL' TV out without requiring software
deinterlacing. Is this a correct assumption?
Also, would the change in resolution cause issues with the picture
being scaled and the interlacing being messed up?
I don't know if I'm making this more complex than it actually is
because it seems to be quite hard to follow :)

Dan