Data Compression for the Web

Data compression involves reducing file size by either discarding unnecessary data or by use of algorithms that look for repeating patterns in data (redundancy).

Visit the sites below then answer the following questions;

http://computer.howstuffworks.com/file-compression.htm/printable

http://computer.howstuffworks.com/question408.htm


1. Name two programs used for file compression.

• WinZip
• WinRAR

2. What name is given to the file compression method that looks for redundant patterns? Why can't music be compressed efficiently with this type of compression technique?
LZ adaptive dictionary-based algorithm (LZ being the initials of the algorithms creators Lempel and Ziv). Music cannot be compressed efficiently with this compression technique because music does not have repeating patterns. 

3.What method of compression is most suited to graphics and music files?
Lossy and lossless compression which works by compressing data by discarding (losing) some of it. The procedure aims to minimize the amount of data that needs to be held, handled, and/or transmitted by a computer.

4. Name compressed file formats for the following media:

• music: MPEG
• still graphics: JPEG
• audio: MPEG
• video: Shockwaves

Use Gimp (Start > Programs > Gimp2) to open an image and then save it as a jpeg with different levels of compression. Paste these images below. Explain why the appearance of the images varies