TVs as monitors

[dsr at tao.merseine.nu]

On Sat, Apr 10, 2004 at 04:33:39PM -0400, Doug Sweetser wrote:
> What would be required to control the TV?  Could it be done with
> S-video input, whatever that is?  It would be a cool upgrade to go
> from 15" to 27".

So, today's lesson is about resolution. Technically, resolution means
dots-per-inch, but everyone uses the word to mean "total viewable
pixels".

NTSC television signals can be handled in 320x200, and that's about the
res of your standard TV set. Those 27" $200 sets at Costco? NTSC. 80
column text will tend to be rather blurry. X will be essentially
unusable, unless you're already used to running it on a PDA. At best,
the TV might do 640x480. Maybe. 

ATSC signals are digital, and come in a variety of formats: 480i, 480p,
720i and p, 1080i. The i means interlaced: even numbered frames display
even-numbered rows of pixels, and odd frames display the odd rows. This
cuts down on the bandwidth but increases flicker. P means progressive,
like a monitor: all rows get shown each frame.

A TV set that can do 720p is just about usable as a monitor: it will
probably even come with a VGA or DVI video port. A 1080i TV is probably
a decent monitor, and will certainly come with a VGA or DVI port without
too much looking around.

Now compare prices of ATSC (High Definition) TVs to monitors of the same
size.

-dsr-