[mythtv-users] TV-Out: AITech Scan Converter vs CX2587x

[Edward Wildgoose]

Well, I'm having a hard time finding anything, but take a look at this

http://www.tech-report.com/news_reply.x/4689/1/

It is a review of a Radeon 9500 which points out that the SVideo socket has some extra pins.  If you read the comments below, several people note that this supplies RGB out, and on some cards even spdif (?!).

I wonder if quite a few cards, especially ATI cards have RGB outputs then...  Just not advertised loudly...  

The problem of course with the ATI cards is getting the darn tvout to actually do anything, but presumably that aside if it did work, then you would be getting signals at the correct freq because they are coming out of the TV side rather than the vga side...?

Other stuff I noticed: Check out the Matrox Parhelia (sp?) which claims to have excellent quality TV output, and there is a diagram on their website for european enthusiasts to build a SCART cable.  It appears to need driver assistance, and I'm guessing that the linux driver doesn't do tv?

Also, the new Hollywood plus replacement (X something..?) seems to have component out, possibly RGB out.  I wonder what modifications are required to mythtv to support Hollywood type decoders?  There is an addon to vdr which supports these cards, I might take a look at the code to get an idea of exactly what is involved.

So scratching the surface, but the most promising appears to be the graphics cards with extra pins on the TV-out...



-----Original Message-----
From: Erik Arendse [mailto:erik_nospam.arendse at bigfoot.com]
Sent: 10 April 2003 11:30
To: Discussion about mythtv
Subject: RE: [mythtv-users] TV-Out: AITech Scan Converter vs CX2587x


At 10-4-03 11:45, you wrote:
> > Where you can get a *great* boost in quality is if your TV has R/G/B inputs
> > (a la SCART), that way your tv doesn't have to unmuddle
> > Chrominance/Luminance/??
>
>I just accidently discovered that my TV has RGB input via the scart 
>socket!  Never noticed before, but the difference after switching the DVD 
>player to RGB is stunning!
>
>Now how to I find a VGA to RGB convertor?  (in the UK)

Forget it, most modern video cards cannot create the timings for a good PAL 
signal. The signal level  conversion though is a breeze, see: 
http://www.sput.nl/hardware/tv-x.html

The TV-OUT from modern cards is created by scaling and re-timing the VGA 
but has no RGB available outside the chip. Even so these scalers are 
terrible. (About as bad as the external VGA->TV converters people use on 
this list. No way a $100 scaler is using a decent Faroudja chip.)

The most noticible exception is the Matrox G400, it creates a perfect 
RGB/PAL signal  and beats anything else from the PC to the TV-screen 
(besides VGA to a DLP beamer). Maybe the G200 can do the same, but I have 
no firsthand experience.
But do realize you still have to build the 1-transistor circuit at the link 
above, the output cable you get is just S-VHS.

The problem seems to be the big US market where size is important, and 
quality less so. Even non-HDTV projection TV's with only composite in are 
sold there, you can imagine the picture quality... So the cardmanufacturers 
just put composite on the cards, or perhaps Y/V, nobody uses RGB on TV.
Only on the newer generation of beamers you are not limited in quality by 
the connection.

If you look for VGA cards with SCART out you will be disappointed, all I 
could find were only CVBS, sometimes Y/V. Non used real RGB on the scart. 
But I would like to stand corrected on this :-)

Erik

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