Svideo out to TV quality is really poor
 

Hi all,

At my place of work, I have been asked to feed the output from a PC to 16 LCD TVs, but before going ahead and buying distribution amps and the like, I thought it just as well to test the SVIDEO out socket to make sure it works OK.
Well, it does work, but the quality is pretty poor to say the least. It is certainly not something you could use, even on an hourly basis. The picture is really soft, and looks completely out of focus, and it makes no difference whether X is up and running or not. Just to double check, I tried on both LCD and CRT, and with Nvidia and ATI cards, workstations and laptop, and it is always the same poor quality. Just to double check, I even tried on that 'other' operating system, and the results are once again the same.

So, my question, how do I improve the quality of the output from the svideo socket, or is the output just really p*** poor from a PC, and I am barking up a tree I am unable to climb.

Almost forgot to mention, also tried a fancy VGA to svideo converter, and the quality is just as bad.

Any suggestions anyone.
TIA

What kind of video source are you using? I've got quality picture out of svideo so it's possible. Unless you use Vista-approved hardware of course. ;)

Mainly it will be used to show web pages consisting of text and some animated flash. And that is the problem. Text is really bad. So much so that it hurts your eyes to try and read it. I would say that I have tried a DVD and it's fine with that. But to try and use it as a desktop environment is pretty much unuseable.

Yeah, considering TV picture has only 625 lines it cannot be very good, right? Or are those LCD's HDTV? You may get some ideas about LCD rendering here but I do not think there is a perfect solution.

Edit: What's the TV standard in the UK anyway?

LCD are digital displays. For S-Video to work on a LCD, it have to be converted from analog to digital. Some LCD have good conversion and others do not. If the LCD have an DVI-D connection, the quality will be a lot better. For all LCD, they have to be displaying the content at their native resolution to provide the best picture.

S-Video and Composite (RCA) connections are not designed to display text. Also these connections have very low resolution at about 360x240 for NTSC and 360x288 for PAL. The refresh rate also ruins the quality, but mostly for movement. I suggest a refresh rate of 60 for NTSC and 50 for PAL. To fix the problem, I suggest using font size of 24 or larger and using a resolution set at 640x480. The refresh rate I suggest using is 60 hertz for NTSC and 50 hertz for PAL. If the CRT or LCD monitor can not handle these low refresh rates, I suggest 120 hertz for NTSC and 100 hertz for PAL.

All S-Video or Composite cable should be shielded. For extra protection, I suggest cables with ferrite ends to reduce EMI (Electromagnetic Interference). Also the cable should not be any longer than 9 feet (2.7432 meters).

Web pages are not designed well for TV, but only if they are designed for WebTV.

I suggest using a program to magnify an area. There are several programs out there for Linux. In popular desktop or window managers, they are in the accessibility section.

That's interesting. Are you sure S-Video output cannot get higher res?

Composite or RCA have the same resolution. S-Video just has separate wires for chrominance and luminance for a a more detail picture than Composite can provide.

I forgot to add that PAL users can probably get a way with 800x600, but they are going to lose some information. Also cheap LCD monitors uses 6-bit color for each of the three colors, so only 15-bit of color (32768 colors) can be used effectively.