COMPRESSION

Compression: Lossless Compression and Lossy Compression



Abstract

Data compression is the process by which statistical structure in data is used to obtain a compact representation for the data. Structure can exist in data in various ways. If there is a correlation between neighboring symbols, this correlation can be used to remove the predictable portion of the data and encode only what remains. The advantage of lossy methods over lossless methods is that in some cases a lossy method can produce a much smaller compressed file than any known lossless method, while still meeting the requirements of the application (Solari, 1997). Lossless compression algorithms usually exploit statistical redundancy in such a way as to represent the sender's data more concisely, but nevertheless perfectly. Lossless compression is possible because most real-world data has statistical redundancy. For example, in English text, the letter 'e' is much more common than the letter 'z', and the probability that the letter 'q' will be followed by the letter 'z' is very small (Ratakonda and Ahuja, 2002).

Compression: Lossless Compression and Lossy Compression

Introduction

Compression mentions is method of saving data in a kind that values less space than usual; compressed documents supply the identical rudimentary allowance of facts and numbers, audio, and/or video data as the initial documents, but use less morsels of storage. Current measures of connection, for example the prevalent use of 56.6 kbps modems, necessitate the use of compression methods for experiencing the audio and video content of the Internet. This paper talks about Compression and its types of lossless compression and lossy compression in a concise and comprehensive way.



Compression: Lossless Compression and Lossy Compression

Li, et al (2004) mentions two methods of compression are lossless and lossy. Lossless compression makes documents that, upon decompression, are equal to the initial file; that is, little to no data is lost throughout the process. More broadly utilised, although, is lossy compression, which changes the initial file. Lossy compression methods take benefit of redundancies in the data being retained in alignment to comprise it efficiently. Instead of encoding every part of data accessible, as customary procedures of saving audio and video do (e.g., audiotape, videotape), these methods encode only momentary alterations in audio and/or frame-by-frame alterations in video in alignment to make documents that are lesser than the original. This subtle method is finished through an primary encoding method that recognises the “static,” (Li, et al, 2004) or redundant, data, and after encodes only facts and numbers comprising alterations happening over time. As these alterations build up, they make, for example, action or even a change of view on video. Although this method eliminates data from the initial document, the distinction between the initial and compressed documents is normally untraceable by human auditory and visual senses. MP3s and digital video founded on MPEG measures, for demonstration, use lossy compression.

When compressed newspapers documents are opened, the data is flowed, or conveyed, to a newspapers player. Players, for example the Windows Media contestant and RealPlayer, are programs programs adept of playing compressed ...