Codec

Draft

Definition

1. codec stands for compression/decompression. A codec is a kind of algorithm or a computer program that reduces the size of a file.

1. The term codec is used to design chips that perform data conversion

Compression is used by most multimedia formats like video streaming, digital images (e.g. JPEG and PNG) and music (e.g. MP3). It is also popular for software distribution and archivation, e.g. zip/jar archive files contain compressed files and gzip files archives that are compressed.

Technology

Usually there is a choice of two kinds of features

• loss-less vs. lossy
• High compression ratio vs. high speed compression/decompression

Lossyness

• Lossy compression means that you loose data (e.g. as in MPEG or JPEG).

Here is an example. The number 8.996666 could be compressed as

8.9[2]6[4] -or- 8.9

The second alternative is lossy, but may be good enough for your needs ...

Compressions formats

Lossless

LZW

• Used in GIFs and Unix compress

Deflate (a combination of LZ77 and Huffman coding)

• ZIP, gzip and PNG

Bzip2

• Very high compression rate

Lossy

JPEG

• Digital images, a sequence of several algorithms

MPEG

• A family that includes MP3 and AAC, also a sequence of several algorithms

Links

http://en.wikipedia.org/wiki/Data_compression