Bit depth of imported graphics – Apple Final Cut Express 4 User Manual
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Part IX
Bit Depth of Imported Graphics
Final Cut Express can import graphics with a bit depth of up to 16 bits per pixel per
color channel, although 8 bits per color channel is the bit depth most commonly used.
The more bits used to represent color in an image, the more accurately the color is
represented. This is important when you are trying to preserve color detail in motion
picture or still-image film.
Understanding Digital SD Video Non-Square Pixels
When creating graphics for SD video, you need to consider the fact that the digital
video pixels are considered to be non-square (taller than wide for NTSC video, or wider
than tall for PAL video) compared to your computer graphics program that uses square
pixels. Non-square pixels are also referred to as rectangular pixels.
Note: Some computer graphics programs support non-square pixels, making it simpler
to create graphics for SD video formats like NTSC and PAL. For high definition (HD)
video formats, you can simply create square pixel graphics, which means designing
graphics with exactly the same image dimensions as your HD format.
Reconciling the difference between non-square pixels and square pixels can cause a lot
of confusion for beginning video graphic designers, but the best rules of thumb are to:
 Use a graphics application that supports non-square pixels, such as Adobe
Photoshop. In this case, you create your graphics with the proper dimensions and
pixel aspect ratio throughout the entire post-production process.
 Keep your destination video frame size in mind and follow the table on page 798
when designing graphics in your graphics application.
Note: There is no accepted standard for the exact aspect ratio of non-square SD video
pixels. Different manufacturers may assume different pixel aspect ratios when designing
their software. Fortunately, these differences tend to be very small, so in many cases you
may not notice a difference between pixel aspect ratios of, say, 0.9 and 0.89.