Image Processing Reference
In-Depth Information
2
Why Video Compression
Is Needed
2.1
Every Journey Begins with a Single Step
So you are thinking about compressing some video. It might seem like a daunting subject,
but it isn't really. If you begin with small steps, soon you'll be taking the whole thing in
stride. In this chapter, we will examine the history and significance of video compression,
along with its practical uses—some of the reasons you are on this journey today. There are
quite a few products and services available today that just wouldn't be possible without
compression. Many more are being developed. Let's see what's out there.
2.2
Compression Is Necessary Because . . .
Delivering digital video and audio through the available networks is simply impossible
without compressing the content first.
To give you some history, there has been a desire to deliver TV services through
telephone networks for many years. Trials were carried out during the 1980s. Ultimately,
they were all unsuccessful because they couldn't get the information down the wire
quickly enough.
Now we are on the threshold of being able to compress TV services enough that they
can fit into the
bandwidth
being made available to broadband users. The crossing point of
those two technologies is a very important threshold. Beyond it, even more sophisticated
services become available as the broadcast on-air TV service comes to occupy a smaller
percentage of the available bandwidth.
So, as bandwidth increases and compressors get better, all kinds of new ways to
enjoy TV and Internet services come online. For example, a weather forecasting service
could be packaged as an interactive presentation and downloaded in the background.
If this is cached on a local hard disk, it will always be available on demand, at an
instant's notice. An updated copy can be delivered in the background as often as
needed. Similar services can be developed around airline flight details, traffic condi-
tions, and sports results.
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