Apparatus and method for generating an encoded signal or for decoding an encoded audio signal using a multi overlap portion

摘要

An apparatus for generating an encoded signal, comprises: a window sequence controller (808) for generating a window sequence information (809) for windowing an audio or image signal, the window sequence information indicating a first window (1500) for generating a first frame of spectral values, a second window function (1502) and at least one third window function (1503) for generating a second frame of spectral values, wherein the first window function (1500), the second window function (1502) and the one or more third window functions overlap within a multi-overlap region (1300); a preprocessor (802) for windowing (902) a second block of samples corresponding to the second window function and the at least one third window functions using an auxiliary window function (1 100) to obtain a second block of windowed samples, and for preprocessing (904) the second block of windowed samples using a folding-in operation of a portion of the second block overlapping with a first block into the multi-overlap portion (1300) to obtain a preprocessed second block of windowed samples having a modified multi-overlap portion; a spectrum converter (804) for applying an aliasing-introducing transform (906) to the first block of samples using the first window function to obtain the first frame of spectral values, for applying the aliasing introducing transform to a first portion of the preprocessed second block of windowed samples using the second window function to obtain a first portion of spectral samples of a second frame and for applying the aliasing introducing transform to a second portion of the preprocessed second block of windowed samples using the one or more third window functions (1503) to obtain a second portion of spectral samples of the second frame; and a processor (806) for processing the first frame and the second frame to obtain encoded frames of the audio or image signal.