Sub-band coding: Difference between revisions

Revision as of 18:56, 8 February 2019

Revision as of 00:31, 8 March 2019

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{{no footnotes|date = October 2011}}

[[File:SubBandCoding.svg|thumb|500px|Sub-band coding and decoding signal flow diagram]]

In [[signal processing]], '''sub-band coding''' ('''SBC''') is any form of [[transform coding]] that breaks a signal into a number of different [[frequency band]]s, typically by using a [[fast Fourier transform]], and encodes each one independently. This decomposition is often the first step in data compression for audio and video signals.

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==Applications==

Beginning in the late 1980s, a standardization body called, the [[Motion Picture Experts Group]] (MPEG), developed generic standards for coding of both audio and video. Subband coding resides at the heart of the popular MP3 format (more properly known as [[MPEG-1 Audio Layer III]]), for example.

Sub-band coding is used in the [[G.722]] codec which uses sub-band adaptive differential pulse code modulation (SB-[[ADPCM]]) within a bit rate of 64 kbit/s. In the SB-ADPCM technique, the frequency band is split into two sub-bands (higher and lower) and the signals in each sub-band are encoded using ADPCM.