Pixel aspect ratio
Computer-generated
images are made of square pixels. Digital video is made up of rectangular
(non-square) pixels. In almost every situation that holds true,
and it can cause problems.
DV has a 4 x 3 frame aspect ratio, a 0.9:1 pixel
aspect ratio, and a screen resolution of either 720 x 480 (NTSC) or 720 x 576
(PAL). D1 (another video format a.k.a. CCIR-601 or ITU-R 601) is a non-square
pixel aspect ratio. D1 has a screen resolution of either 720 x 486 (NTSC) or 720
x 576 (PAL), and a .9:1 pixel aspect ratio. DV and D1 images are composed of
rectangular (non-square) pixels, not the square pixels for most Mac OS and
Windows systems.
Graphics applications usually create square pixel files, so most graphics
imported into a D1 or DV project have a square pixel aspect ratio. When
importing an image created by a square-pixel graphics program into a video
editing program, the square pixels are scaled to the non-square pixels for video
encoding. This scaling results in a distorted image.
APAS/Wizard supports non-square pixels.
Image type |
Pixel aspect ratio |
Square |
1:1 |
D1/DV NTSC |
0.9:1 |
D1/DV NTSC wide angle |
1.2:1 |
D1/DV PAL |
1.066:1 |
D1/DV PAL wide angle |
1.42:1 |
Anamorphic |
2:1 |
See also