Data Compression !

Data compression has been omnipresent since ancient past,

•      Number systems
•      Natural languages
•      Mathematical notation

Has played a central role in communications technology,

•      Braille
•      Morse code
•      Telephone system

And is part of modern life

•      zip
•      MP3
•      MPEG

 

Compression reduces the size of a file:

1. To save space when storing it.

2. To save time when transmitting it.

3. Most files have lots of redundancy.

Encoding and Decoding:

• Message: Binary data M we want to compress.
• Encode: Generate a "compressed" representation C(M).
• Decode:Reconstruct original message or some approx. M'.

Applications:

1. Generic file compression:

Files: GZIP, BZIP, BOA

Archivers: PKZIP

File systems: NTFS

2. Multimedia:

Images: GIF, JPEG

Sound: MP3

Video: MPEG, DivX, HDTV

3. Communication:

Fax

SMS

4. Databases:

Cloud Computing

Servers