频变扩展重迭变换的快速算法

Fast algorithm on frequency-varying extended lapped transforms

频变扩展重迭变换(FV-ELT)是一类具有灵活时频分辨率特性的非均匀滤波器组,适用于音频编码中时频映射处理部分。本文主要给出基于DCT-IV的FV-ELT快速算法,并给出复杂度计算公式。最后以几种典型滤波器组应用结构为例,给出了所需乘加运算次数。与直接计算模式相比,此快速算法能有效地降低FV-ELT的运算复杂度。

Frequency-Varying Extended Lapped Transform （FV-ELT） is a set of nonuniform filter banks with a flexible time-frequency resolution property, which is adapted to time-frequency mapping of audio encoding. The fast algorithm of FV-ELT based on DCT-IV is presented in the paper, and the complexity expression is also derived. According to a few examples for filter banks with typical structures, the number of multiplications and additions are figured out. The complexity can be dramatically reduced while compared with a direct calculation from the definition of FV-ELT.