Audio Encoder, Audio Decoder, Encoded Audio Information, Methods for Encoding and Decoding an Audio Signal and Computer Program

An audio decoder for providing a decoded audio information on the basis of an encoded audio information comprises a window-based signal transformer configured to map a time-frequency representation, which is described by the encoded audio information, to a time-domain representation. The window-based signal transformer is configured to select a window, out of a plurality of windows comprising windows of different transition slopes and windows of different transform length, on the basis of a window information. The audio decoder comprises a window selector configured to evaluate a variable-codewordlength window information in order to select a window for a processing of a given portion of the time-frequency representation associated with a given frame of the audio information.