Hey Bob, you seem, to know your stuff so perhaps you could give me some
insight into something I have always wondered about with some of the HD
Plasma screens. Quite a few of the earlier HD plasma screens have a
native res of 1024x768. That means to get a 16:9 ratio they would have to
use rectangular pixels, right? Well, 1024x768 is not even an HD res so
how can they call them HD? Sure my friends HD Plasma displays 1280x720
but it just upscales 1024x768 to 1280x720, right?
First - yes, a 16:9 panel which has a native format (a
term I prefer over "resolution," but then I'm picky about
such things - "resolution" in imaging has its own meaning
already) of 1024 x 768 must have, by necessity,
"non-square" pixels - and an image created in a different
format would have to be scaled to fill that screen. That
turns out to be not much of a concern, at least from the
perspective of the earlier (Japanese analog system) days
of HDTV. Analog video doesn't really have any such thing
as "pixels" to begin with, so the panel format is mostly
concerned with how many pixels you need for the image to
look good at a given diagonal size and assumed viewing
distance (and that IS a question of "resolution" in the proper
sense - something you talk about in terms of pixels per inch,
or cycles or lines per visual degree).
Second - they can call it "HD" because that term really
has no special meaning in terms of a particular pixel
count. The de-facto meanings today are "HD = 1280 x
720," and "Full HD = 1920 x 1080," but such things
really have no basis in terms of established standards.
HD really just means "high definition," and anything we've
talked about so far certainly does have at least HIGHER
definition that the earlier "standard definition" 480 or
576-line broadcast formats.
And why did the HD LCD screens use 1366x768 instead of 1280x720?
Actually, both have been used - but as noted earlier, it
can at least be argued that the 768-line version gives you
somewhat of a better match to PC standard formats (if
you care about such things), and more pixels on the screen
anyway. "Scaling" isn't something the TV industry has
really had to avoid, since no matter what you choose for the
panel format, you're going to HAVE to scale some incoming
video anyway. Scaling is not necessarily a bad thing, at least
not when you're talking about something like typical "TV"
images.
Bob M.