Apple Motion 3 - Manual (Page 1214)

1214 Appendix B Video and File Formats
Working with Standard Definition (SD) Video Monitors
and Computer Displays
Standard definition (SD) video monitors differ from computer displays in a significant
way (aside from interlacing): computer displays represent images using a grid of
square pixels, while video monitors use pixels that are rectangular in shape.
SD NTSC pixels are narrower than computer pixels and SD PAL pixels are wider than
computer pixels. As a result, a 720 x 486 pixel image looks different on a computer
display than it does on a video monitor. For example, if you capture a clip of video with
a globe in the picture, export a frame, and look at this frame in a graphics application,
you’ll see something like this:
The Canvas let you display nonsquare pixel video correctly on the computer’s screen
using the Correct For Aspect Ratio command in the View pop-up menu above the
Canvas.
Note: High definition video uses only square pixels, so it doesn’t show this discrepancy.
720 x 486 Broadcast
(720 x 480 DV)
640 x 480
Looks right
on a video monitor
NTSC square vs. nonsquare pixels example
Looks wrong
on a computer monitor