TVs as monitors

[Mark J. Dulcey]

dsr at tao.merseine.nu wrote:
> On Sat, Apr 10, 2004 at 05:05:40PM -0400, Bill Horne wrote:
> 
>>I think the S-video inputs are capable of much higher resolutions than
>>NTSC (known in the trade as "Never Twice the Same Color"). The first
>>step is to visit your local video store and talk about capabilities with
>>the eager salesmen: if it can be done, they'll want to sell it to you.
> 
> 
> Nope, sorry. All S-Video does is send the same NTSC signal with the
> chrominance and luminance signals on different wires, giving better
> crosstalk rejection, but no improvement in resolution.

The effective horizontal resolution is significantly better, because the 
luminance is no longer messed up by the comb filter. (You don't even 
want to think about what happens on a set that has a low-pass filter 
instead of a comb filter, but such sets probably don't have S-video 
inputs anyway.) The vertical resolution is still limited by the number 
of scan lines, however. The signal format doesn't actually impose any 
theoretical limit on the bandwidth of the luminance signal (over cables; 
the broadcast bandwidth is limited), but the dot pitch of a TV tube will 
impose an upper bound of 800 pixels or thereabouts (lower for a small or 
cheap set).

If you are feeding video from a non-composite source (S-VHS VCR, 8mm or 
digital camcorder, DVD player, satellite or digital cable set-top box, 
or computer) into a TV set, an S-Video connection will usually give you 
a visibly better result. Component video will usually be better still, 
as it eliminates the bandwidth limits of the encoded chroma signal.

None of these things are a substitute for a real high-resolution signal 
from a computer, HDTV set-top box, D-VHS VCR. high-resolution camcorder, 
or upcoming HD DVD. Any of those will be dramatically better than 
anything you can feed through an S-video connection.

To return to a point from my previous message, TV-out is widely 
available on modern video cards, and just about free once you get past 
the really low-end cards. (You'd be hard pressed to find an over-$100 
card that DOESN'T have TV out, other than a specialized workstation 
video card.) There is no good reason not to include it in a new 
mid-range or higher PC; it is handy on occasion, especially if you like 
to do group computer gaming.