[mythtv-users] vga2scart interlacing on UK Channel 4
simbloke at googlemail.com
Sun May 20 21:26:39 UTC 2007
On 15/05/07, Tom Hughes <tom at compton.nu> wrote:
> In message <cc22fa3b0705150236t11fa13f2ge7618e4857b8e0a8 at mail.gmail.com>
> Simeon Walker <simbloke at googlemail.com> wrote:
> > I've made a VGA to SCART cable for an NVidia 6150 based board. I'm
> > tesing with MiniMyth 0.20-21.
> > The modeline I'm using is: "720x576" 13.875 720 744 808 888 576 581
> > 586 625 -hsync -vsync interlace
> > Everything thing is good except on recordings from Channel 4, More 4
> > etc. It looks like the fields are displayed in the wrong order. It
> > doesn't seem to matter what I select from the OSD menu regarding,
> > detect/progessive/interlaced/reversed.
> > I know there are a few people here using these cables, so have any of
> > you had such a problem?
> Yes, it's a well known problem with no known solution.
> I don't find that it is channel specific - in fact it tends to come
> and go as you watch because there is no way to know which field the
> video card is outputting so no way to know which field to give it so
> even if you use OpenGL or something to sync correctly it is entirely
> random whether the fields come out in the right order or not.
After making a few more recording I certainly see it's not restricted
to C4. It is usually impossible to cure using the video scan menu.
I would have thought that the vsnyc interrupt would come at 25hz in an
interlaced mode, if it still comes at 50hz that could explain a lot.
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