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MEDIASTUDIO PRO USER GUIDE
just a few. The main reason for choosing 8-bit over 24-bit is that you can
control the range of colors that appear in an 8-bit file by using a color
palette. This ensures that your video will display equally well on machines
running in 256 color display modes (often the requirement for those
seeking to distribute video on CD-ROM or over the Internet).
Understanding video compression
While frame rate, frame size and data type all contribute to controlling the
transfer rate, the real savings come from effective use of compression. In
general, there are two types of compression used in the digital video
world: spatial (intraframe) and temporal (interframe). By combining
these methods, video files can be saved at a fraction of the size required
for their uncompressed counterparts. For example, compression schemes,
such as MPEG, first compress the images in certain frames of a video by
finding repeated or similar patterns in the image. Then, the compression
method refers to preselected frames, (key frames) and creates baseline
data to compare against the information in the following frames. This
time, the compression method seeks differences from the previous frame
and discards everything else. It is for this reason that videos that use a
limited number of colors and easily identified patterns, such as cartoons,
tend to compress very well, while those with much greater colors and
more random patterns, such as live video recordings, require larger file
sizes.
Motion JPEG
The JPEG compression scheme works by compressing each frame in a
video sequence. It is not the most efficient in regard to file sizes, but by
compressing every frame individually, it offers the best quality and is the
scheme of choice for people wanting to output back to video tape or
broadcast. To do this, however, you will need a lot of storage space and a
high-end video capture board that can handle large amounts of data and
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