Open AccessEfficient binary search space‐structured VQ encoder applied to a line spectral frequency quantisation in G.729 standard
Author(s) -
Lin TzuHung,
Yeh ChengYu,
Hwang ShawHwa,
Chang ShunChieh
Publication year - 2016
Publication title -
iet communications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.355
H-Index - 62
eISSN - 1751-8636
pISSN - 1751-8628
DOI - 10.1049/iet-com.2015.0729
Subject(s) - codebook , binary search algorithm , vector quantization , algorithm , encoder , binary number , search algorithm , code word , computer science , reduction (mathematics) , encoding (memory) , lookup table , mathematics , benchmark (surveying) , artificial intelligence , decoding methods , arithmetic , geometry , geodesy , programming language , geography , operating system
This study presents a simple but high performance vector quantisation (VQ) codebook search algorithm for line spectral frequency quantisation in ITU‐T G.729 speech codec, designated as the binary search space‐structured VQ (BSS‐VQ) algorithm. This is done through a combined use of a fast locating technique and lookup tables, such that an input vector, ahead of VQ encoding, is assigned efficiently to a subspace where merely a small number of codeword searches are required to be performed. As a consequence, the computational load is reduced remarkably. A trade‐off can be made easy to meet a user's requirement when performing VQ encoding. It is experimentally validated that a search accuracy is well maintained at 99% approximately for a threshold of quantisation accuracy of 0.99. More importantly, with a full search algorithm as a benchmark for search load comparison, this proposal provides a 85% search load reduction, a figure far beyond 43% in multiple triangular inequality elimination approach, 47% in TIE with dynamic and intersection rules and 59% in quasi‐binary search VQ algorithm.