Compression

• The process of reducing the size of a object is called compression.
• Compression takes place when something is squished together.
• Compression comes from the Latin word compressare.

Data compression

• Data compression is a reduction of bit to reduce the size of files.
• It can be done all type of file like audio, video, images.
• Compressing data can save storage capacity, speed file transfer, and decrease costs for storage hardware and network bandwidth.

Types of data compression

Lossless compression

• When an image is compressed and later uncompressed using lossless algorithm the data is exactly same is called lossless compression.
• It reduces file size by compressing only the non-essential part of data.
• It can store data in less space.
• Lossless techniques are run-length, huffman and lempel-ziv.
• It is used in the ZIP file format and in the GNU tool gzip.

Lossy compression

• Lossy compression produced data which may be slightly different from original data.
• It reduces file by permanently eliminating the data.
• It averages a group of pixel to compress the data.
• It achive higher compression rate than lossless.
• Lossy techniques are JPEG, MPEG and MP3.

In computer we can compress data as following:-