Fast algorithm for the modulated complex lapped transform

A new algorithm for fast computation of the modulated complex lapped transform (MCLT) is presented. For a length-M MCLT, the algorithm is based on computing a length-2M fast Fourier transform plus M butterfly-like stages, without data shuffling. That reduces the number of operations and memory accesses needed to compute the MCLT when compared to previous algorithms. Compared to the original type-4 discrete-cosine-transform-based algorithm, an implementation of the new algorithm leads to 25% faster execution.