APPARATUS AND METHOD FOR ENCODING OR DECODING AN AUDIO SIGNAL USING A TRANSIENT-LOCATION DEPENDENT OVERLAP

摘要

An apparatus for encoding an audio or image signal, includes: a controllable windower for windowing the audio or image signal to provide the sequence of blocks of windowed samples; a converter for converting the sequence of blocks of windowed samples into a spectral representation including a sequence of frames of spectral values; a transient location detector for identifying a location of a transient within a transient look-ahead region of a frame; and a controller for controlling the controllable windower to apply a specific window having a specified overlap length to the audio or image signal in response to an identified location of the transient, wherein the controller is configured to select the specific window from a group of at least three windows, wherein the specific window is selected based on the transient location.

主权项

1. Apparatus for encoding an audio signal, comprising:
a controllable windower for windowing the audio signal to provide a sequence of blocks of windowed samples; a converter for converting the sequence of blocks of windowed samples into a spectral representation comprising a sequence of frames of spectral values; a transient location detector for identifying a location of a transient within a transient look-ahead region of a frame; and a controller for controlling the controllable windower to apply a specific window having a specified overlap length to the audio signal in response to an identified location of the transient, wherein the controller is configured to select the specific window from a group of at least three windows comprising a first window having a first overlap length, a second window having a second overlap length, and a third window having a third overlap length or having no overlap, wherein the first overlap length is greater than the second overlap length, and wherein the second overlap length is greater than the third overlap length or greater than an overlap of zero, wherein the specific window is selected based on the transient location such that one of two time-adjacent overlapping windows comprises first window coefficients at the location of the transient and the other of the two time-adjacent overlapping windows comprises second window coefficients at the location of the transient, wherein the second coefficients are at least nine times greater than the first coefficients.