Image Processing Reference
In-Depth Information
Parlez-Vous Compressionese?
A few readers may be unfamiliar with the jargon we use. Words such as codec might not
mean a lot to you at this stage. No need to worry—jargon will be explained as we go along.
The important buzzwords are described in a glossary at the end of the topic. Glossary
entries are italicized the first time they are used.
The word codec is derived from coder-decoder and is used to refer to both ends of the
process—squeezing video down and expanding it to a viewable format again on playback.
Compatible coders and decoders must be used, so they tend to be paired up when they are
delivered in a system like QuickTime or Windows Media. Sometimes the coder is provided
for no charge and is included with the decoder. Other times you will have to buy the coder
separately. By the way, the terms coder and encoder in general refer to the same thing.
Tied Up With Your Cabling?
Because there are so many different kinds of connectors, where it is helpful, there are dia-
grams showing how things connect up. In Appendix M, there are pictures of the most
common connectors you will encounter and what they are for. Even on a modest, semi-
professional system, there could be 10 different kinds of connectors, each requiring a spe-
cial cable. FireWire and USB each have multiple kinds of connectors depending on the
device being used. It is easy to get confused. The whole point of different types of con-
nectors is to ensure that you only plug in compatible types of equipment. Most of the time
it is safe to plug things in when the cable in your left hand fits into a socket in the piece of
hardware in your right (okay, if you are left-handed it might be the other way around).
Knowing whether these connections are “hot pluggable” is helpful, too.
Hot-pluggable connections are those that are safe to connect while your equipment is
turned on. This is, in general, true of a signal connection but not a power connection. Some
hardware, such as SCSI drives, must never be connected or unconnected while powered on.
On the other hand, Firewire interfaces for disk drives are designed to be hot pluggable.
So You Already Know Some Stuff
Chapters 2 to 7 may be covering territory you already know about. The later chapters
discuss the more complex aspects of the encoding process and will assume that you
already know what is in the earlier chapters or have read them.
Video Compression Is Not Exactly New
Video compression has been a specialist topic for many years. Broadband connections to
the Internet are becoming commonplace, and consumers are acquiring digital video cam-
eras. Those consumers all have a need for video compression software.
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