12
Chapter 1: Basic Concepts And Tips
Square vs. Non-Square Pixels
There are still a few video editing applications (not to mention computer software in
general), that assume you are working in a resolution that uses square pixels, that is, a
resolution that has the same number of pixels horizontally and vertically for a given
length. More specifically, these video editing applications assume that full-screen video
resolution is 640 x 480 (NTSC) or 768 x 576 (PAL).
Some video products, such as the TARGA 3000, utilize resolutions with non-square
pixels. As mentioned previously, the resolution of NTSC for TARGA 3000 is 720 x 480.
On a video monitor, the video signal displays more pixels in the horizontal direction than
in the vertical direction for a given length. As a result, NTSC pixels are rectangular, taller
than they are wide, on the video monitor. The situation is reversed in PAL where the
resolution is 720 x 576. In this case, the rectangular pixels are wider than they are tall.
This merging of the square and non-square pixel worlds manifests itself in a variety of
ways, some of which have already been described. In general, they will not affect your
work but you should nonetheless be aware of the implications.
Displaying Serial Digital Clips On A Computer Screen
The non-square nature of the serial digital format is most obvious with some software
CODECs when you play back a serial digital clip on your computer screen. The taller,
rectangular NTSC serial digital pixels are stretched horizontally to square pixels on the
computer screen and the image appears slightly “squashed.” The wider, rectangular PAL
serial digital pixels are stretched vertically to square pixels on the computer screen and the
image appears slightly “scrunched.” The diagram following illustrates this phenomenon
for NTSC:
To Next Page
Loading...
Need help?
General
