[Gllug] TV-Out under Linux

[Alex Hudson]

On Fri, 2002-01-18 at 00:37, Dan Kolb wrote:
> I remember seeing in the Maplin catalogue (Summer 2000) an ISA card that 
> takes an input a VGA signal at 640x480 (using a pass-through cable like the 
> Voodoo cards used) and spitting out a PAL signal through a composite (IIRC) 
> output. Thirty quid.
> I haven't tried it, so I don't know if it works or not, but it looks like it 
> should be OS independent.

I have tried them; they're pretty rubbish. The first thing you need to
do is alter your X modelines - they don't 'generate' PAL, they munge the
VGA signal sufficiently such that a TV will display a picture. It will
operate at higher resolutions, but you have to stick the refresh at
50/60Hz (TVs will generally lock at 60; other equipment may not).

The worst thing you will notice about them is the colour bleed. The
cards are unable to delay the brightness signal for long enough
internally, so the colour arrives a little too late and you get a 5/6
pixel bleed, esp. strong colours like green.

If you're willing to spend 80UKP+ you can get a proper unit with a
framestore - this will digitally sample the VGA signal and create a true
PAL signal. They also have 'eccentricities', but a framestore won't
bleed and will generate a better picture. It's also more likely to work
with a wider range of input signal.

Cheers,

Alex.

-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 240 bytes
Desc: not available
URL: <http://mailman.lug.org.uk/pipermail/gllug/attachments/20020118/1a727da3/attachment.pgp>