6 Nov
2007
6 Nov
'07
1:04 a.m.
Jules Richardson wrote:
Hiya,
What would happen if you used one of the video cards that has
the video in/out jacks and setup to input PAL video? Most of
those cards have quite a few options as to how they treat the
video. I haven't tried it but I would expect it to receive PAL
format video input and display a usable picture on the PC screen.
First, have you tried Linux with tvtime and a
boring old analogue BT878
capture card?
I think I've tried three different BT878-based TV cards in Linux - I've
only ever got one of them to semi-work (despite them working in Windows
- albeit at awful quality and in a tiny little window on the desktop
that makes them next to useless anyway). That's against a TV signal too
- I've heard from several sources that TV cards have a real problem with
the modulators used in typical 8-bit micros (UM1233 etc.)
The Linux code for TV cards seems to be something on an undocumented
mess :-(
It seems like a lot of unnecessary complexity to go TTL->composite->RF
and then back to digital again, too.
Also does it have to be attached to a PC? You
could try adapting the RGB
output to a PC VGA monitor directly.
No, I don't need a PC. I just need *something* in the US that can cope
with typical UK-style picture formats (typically 'home' micros in the UK
will be designed around PAL signals at 625 lines interlaced I expect,
whereas I expect US micros of the 80s were geared more toward NTSC
displays of 525 lines)
I'm not sure if VGA will cope either - I don't think a typical VGA
monitor will sync down to the frequencies involved (i.e. converting TTL
to the necessary 'analogue' RGB of VGA is the easy bit :-)
Oh, sync lines on the machines I've got are typically composite, so some
sort of sync separator would be needed too...
This just strikes me as the sort of project that people will have done
before, because monitors take up lots of space and because there's not a
lot of sense in going from a digital source to analogue and then back to
digital again.
cheers
Jules
.