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Multi-Rate Sub-Band Coding of Audio and Video in an ATM Environment

IP.com Disclosure Number: IPCOM000037310D
Original Publication Date: 1989-Dec-01
Included in the Prior Art Database: 2005-Jan-29
Document File: 2 page(s) / 68K

Publishing Venue

IBM

Related People

Derby, J: AUTHOR [+4]

Abstract

The problem of sub-optimum use of transmission links in todays networks results in two main drawbacks: network congestion in case of node overload, and single class of service, based on the quality obtained at a fixed bit-rate. Considering the Asynchronous Transfer Mode (ATM) as a basis for the transfer technique of broadband networks, multi-rate sub-band coding allows to define a flexible architecture providing different classes of services corresponding to different levels of quality with an optimum use of the bandwidth for all types of audio and video signals. At the same time it solves the problem of network congestion.

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Multi-Rate Sub-Band Coding of Audio and Video in an ATM Environment

The problem of sub-optimum use of transmission links in todays networks results in two main drawbacks: network congestion in case of node overload, and single class of service, based on the quality obtained at a fixed bit-rate. Considering the Asynchronous Transfer Mode (ATM) as a basis for the transfer technique of broadband networks, multi-rate sub-band coding allows to define a flexible architecture providing different classes of services corresponding to different levels of quality with an optimum use of the bandwidth for all types of audio and video signals. At the same time it solves the problem of network congestion.

Sub-band coding is an efficient coding technique. Its principle is to decorrelate the input signal by spectral decomposition. The spectrum of the input signal is split into different sub-bands, and each sub- band signal is optimally quantized or further encoded using other efficient coding techniques to remove the residual redundancy in the sub-band.

Asynchronous Transfer Mode is a new technique which can be used to transmit coded information with constant quality: Time decoupling between the source and the network allows the encoder to define its output bit-rate. A variable bit-rate coder allows to keep the same level of quality of the encoded signal regardless of the variation of the information content.

The spectral decomposition of the sub-band coder can be used as a basis...