Fast time scale modification using envelope-matching technique (EM-TSM)
Time scaling of speech and audio signals is one of the key features of the upcoming MPEG4 standard. Synchronized Overlap-and-Add (SOLA) is a time scaling algorithm known to achieve good speech quality. One problem of SOLA is that it requires a large amount of computation in the search of the best matching point between the analysis and synthesis frames. This is especially serious when multiple time scaling factors are to be supported as in the case of MPEG4. In this paper, we propose a technique called envelop-matching to simplify the computation with effectively the same quality. In envelop-matching, zero crossing locations are used as features for the search. We propose a very fast algorithm for the distortion computation.