Data Compression
Data Compression
I'd been promising to write a piece on the topic of data compression for a while. Hopefully I can shine some light on the subject to give you a better understanding of what is going on. It is quite simple once you have got your head around 3 basic concepts.
1) Think of a computer file as a container, cardboard box or an envelope. It can hold something of a certain size.
2) Think of a computer image as an egg tray or a piece of graph paper. It has a set number of positions depending on how many pixels are in the image. Therefore the image in the video display memory of the computer is of a fixed size.
3) The amount of Information an object contains. This concept more abstract and not so easy to grasp.
Lets take an object like a sheet of A4 paper with printed text.
In our first example it just has the words "Hello World"
The second example is say an Electricity Bill. It will contain the following sort of information. Addresses, telephone numbers, prices, units used, dates, taxes and so on.
So our second example contains much more information then the first one. Therefore the first example only needs a small sheet of paper compared to the larger sheet required for the bill.
It then follows that a smaller envelope or container can be used to hold the first example.
The Key point being there was a lot of wasted ( redundant - unused ) space on the "Hello World" example.
I will leave you with these concepts to let them soak in before looking at what methods are used.
Data Compression is about finding a more efficient code to hold the information.
If the information is already stored efficiently with no waste then it will not be easy to compress it further.
Are you all with me so far ?
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