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Using compression
As previously mentioned, a second of video requires a lot of disk space
(30MB of disk space). No conventional hard drive can transfer that much
data with sufficient speed, and it is only through compression that desktop
systems can manage to work with video. All in all, there are two types of
compression one can use in capturing video: hardware-based and
software-based.
Hardware-based compression (e.g. MJPEG or MPEG) relies on the
additional memory of the video capture board to compress video. This
provides the smallest file sizes with the best quality. The only disadvantage
of using this type of compression is that the video you've captured can only
be played back in machines with a similar setup.
Software-based compression (e.g. Cinepak and Indeo) is handled by your
system, which has to share the job of compressing with anything else
running. While software-based compression is unable to match the
compression ratios of hardware-based compression, this type of
compression is device-independent and therefore compatible on a variety of
machines. You can play back the captured video on most computers. This
makes software-based compression the ideal choice for video intended for
distribution on other machines via CD-ROM or the Internet.
Techniques for improving your video captures
Even if you don't have the ideal system for capturing video, you can still
achieve good results by working around the limitations of what you have.
For example, you can:
• Close all other programs that may be running in the background to free
up as much CPU resources as possible.
• Regularly defragment your hard drive with a utility such as Windows
Disk Defragmenter from the Systems Tools menu. (Fragmented drives
force the hard drive to slow down as it has to seek available free space
to save a file.)
VIDEO CAPTURE: CHAPTER TWO
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