[Openchrome-users] VGA to RGB Scart

[Paul Gardiner]

John Robinson wrote:
> On 16/09/2008 10:57, Paul Gardiner wrote:
>> Ivor Hewitt wrote:
>>> It's not possible to get an interlaced signal from the VGA port 
>>> unfortunately. So a VGA-SCART convertor won't work I'm afraid.
>>
>> Shame, but thanks for the info. Best knowing that before
>> building the circuit.
>>
>> My TV can handle progressive 100Hz, I think. Could that
>> be a route forward? Or am I going lose more than I gain
>> in terms of quality?
> 
> If your TV can handle a progressive signal at 50Hz, and claims to be 
> able to do it over the SCART connector, by all means give it a go;

I guess I'm not sure of this. In the TV's menu system, it has a setting
for the scan which has the choices: Natural, Active, 100Hz, Progress.
These settings make a difference independently of input, which for
me is always PAL-I (from a DVB-T source). I'll see if I can find the
manual. I think the TV can handle progressive or interlaced input,
and reorder it on the fly (frame buffering, I guess). It's a
pretty high-spec TV.

> when openChrome is set to 720x576 and TV output, the VGA output produces 
> 720x576 progressive at 50Hz (which my old CRT monitor was perfectly 
> happy with, and my lovely new 24" TFT monitor thinks is 720x480 and 
> crops). And the picture should be as good as you can get on a CRT monitor.

That sounds really hopeful. I thought I might lose quality because
my source DVB-T is interlaced. Wont I get jagged edges on moving
objects? I have some recollection of seeing jagged edges when I first
set up my front end connected to a 1280x1024 LCD monitor. Also I
can see flashing of the refresh when I set my TV to progressive,
although I guess my TV can probably convert back to interlaced if
that's a problem. Overall might be worth it anyway to get the
colours bright again.

> But beware! Do this at your own risk, etc; write your monitor definition 
> in your xorg.conf corresponding to your TV's specs for horizsync and 
> vertrefresh, and don't blame me if you accidentally create a black hole 
> which consumes the world, or whatever...

Ah, that sounds worrying. Would the current modes I'm using for TV
out via S-Video not work? Monitor definitions are a bit of a mystery
to me. Is there any good sources to read up on for this?

Cheers,
	Paul.