Hello,
If Wojo will permit me,
I can understand your confusion...it catches out many.
Pixels on a TV screen do not have a width to height ratio of 1:1...they
are not square. More than that some of what you refer to as pixels are not
displayed at all. In most good DVD creating programs you will see two
rectangular boxes on the composition screen...one is called the action zone
and the other (smaller) is called the safe zone and outside of that is an
area of video that may or may not show on a TV. The area is sometimes
refereed to as Overscan. its where the three beams in a CRT type TV stop and
scan in the opposite direction....this path is called a scanline. In the UK
you can sometimes see individual scan lines if the TV is not set up
properly...you can see a series of small dots moving at the top edge of the
picture, this is where the data for TELETEXT is stored and its also the area
where MacroVision copy protection is stored (and thats why its not
protection of any kind as its very easy to remove)
Anyway, back to the plot.....the way to think of how these pixels are
displayed on a TV screen is to go back to the days of a slide projector. If
the slide was very small but you moved the projector away from the screen
you could get the image to fill the screen but the image would not very
good. But if you widen the aperture and use a larger image, you could move
the projector nearer the screen so as to get the same size image and the
picture would be better because there was more data in it. This example
assumes the same density of pixels per square inch for each image. You will
have noticed that I did not actually mention things like 720 x 480. As a set
of numbers they are not terribly relevant when talking about size of the
final picture as viewed on a TV screen...CRT style TV's use Scanlines. I
think the standard is still the same in the UK...we have 625 horizontal
lines to our TV pictures and some of those are not meant to be seen
(Teletext etc)
So, if you are going for DVD then using "home user" software etc you
would aim for the DV standard that applies in your country and thats the
standard just about all DVD creating software works too. Unless you are
using programs like Nero or Dazzle DVD Complete. Both of these programs are
able to create DVD's to a much higher resolution than the DV standards in
our domestic Digital cameras. I have discovered though that the cheap and
nasty DVD players can't handle the data rate and you get pixelation (Spit)
Hope that helps a little
Best Wishes.....John Kelly
www.the-kellys.org