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Appendix B Video and File Formats 1215
Differences in Color Between Computer and Video Graphics
You should also be aware that the range of colors that can be displayed on a broadcast
video monitor is much smaller than that which can be displayed on your computer. For
this reason, colors that appear bright and clean on NTSC or PAL video can seem duller
when viewed on your computer.
If you output graphics images with colors that go outside the “legal” range for video,
they will appear oversaturated, and may “bleed” into other parts of the image. This
distortion can be easily avoided by controlling the palette of colors you use in your
graphics program. As you create the graphics you’ll be outputting to video, resist the
temptation to use the brightest and most saturated shades of color available in your
paint program.
Using Fonts and Creating Line Art for Video
When creating line art or selecting a font to use for a broadcast video image, you
should avoid creating horizontal single-pixel lines, or using fonts that are too thin.
Because video is interlaced, single-pixel lines will flicker as the field in which they
appear alternates on and off. This results in “buzzing” in your graphics, with the buzzing
becoming more pronounced the closer the thin areas in your image are to horizontal.
This can be lessened by adding a bit of blur or anti-aliasing to your image, but the best
thing to do is to avoid single-pixel lines altogether when creating graphics for
broadcast.
Scaling Imported High-Resolution Graphics
A high-resolution image is useful if you want to pan and zoom in or out of the image,
such as a scanned map or photograph. There won’t be any image degradation because
you typically won’t have to zoom more than 100 percent.
Scaling video and still images more than 100 percent creates artifacts: individual pixels
become noticeable, causing a “stair-stepping” artifact on high-contrast diagonal lines.
Sometimes the frame size of your imported graphic doesn’t match the frame size of
your edited sequence. If the frame size of the graphic is too large, only a small part of
your image appears within the Canvas. If it’s too small, the background color of the
Canvas (usually black) appears behind the graphic.
To scale an imported graphic to match the frame size of a sequence, use the following:
Frame size (pixels) Type of video
1920 x 1080 High definition, 16:9, square pixel
1280 x 720 High definition, 16:9, square pixel