Time warp activation signal provider, audio signal encoder, method for providing a time warp activation signal, method for encoding an audio signal and computer programs

Audio encoder for generating an encoded audio signal, comprising:

• an audio signal analyzer for analyzing, whether a time frame of the audio signal comprises a harmonic or speech characteristic;
• a window function controller for selecting a window function depending on a harmonic or speech characteristic of the audio signal;
• a windower for windowing the audio signal using the selected window function to acquire a windowed frame;
• and
• a processor for further processing the windowed frame to acquire the encoded audio signal;
• wherein the window function controller comprises a transient detector for detecting a transient, wherein the window function controller is configured for switching from a window function for a long block to a window function for a short block, when a transient is detected and a harmonic or speech characteristic is not found by the audio signal analyzer, and for not switching to the window function for the short block, when a transient is detected and a harmonic or speech characteristic is found by the audio signal analyzer;
• and
• wherein the window function controller is configured for switching to a window function being longer than the window function for a short block and adapted to acquire a shorter left-sided overlap length with a previous window than the window function for a long block, when a transient is detected and the signal comprises a harmonic or speech characteristic, such that the window function adapted to acquire a shorter overlap length is used for windowing a speech onset or an onset of a harmonic signal.