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

An apparatus for decoding an encoded audio or image signal, comprising an encoded first frame and an encoded second frame, comprising:

• a processor configured for processing the first encoded frame and the second encoded frame to acquire a first frame of spectral values and a second frame of spectral values, the first and second frames of spectral values comprising an aliasing portion, and the second frame of spectral values comprising a first frame portion of spectral values and a second frame portion of spectral values;
• a time converter configured for applying a transform to the first frame of spectral values using a first window function to acquire a first block of samples, for applying another transform to the first frame portion of spectral values of the second frame of spectral values using a second window function, and for applying further one or more transforms to the second frame portion of spectral values of the second frame of spectral values using one or more third window functions, wherein the applying the another transform and the applying the further one or more transforms are configured to generate a second block of samples,
• wherein the first window function, the second window function and the one or more third window functions form a multi-overlap region, and wherein a second overlap portion of the first window function and a first overlap portion of the one or more third window functions extend into each other in the multi-overlap region having a non-zero length, and wherein the second overlap portion of the first window function is longer than the first overlap portion of the one or more third window functions;
• and
• a post-processor configured for acquiring a post-processed second block of samples comprising a portion of the second block of samples overlapping with the first block of samples in the multi-overlap region, and for overlap-adding a windowed post-processed second block of samples and the first block of samples to acquire a decoded audio or image signal.

A method for generating an encoded audio or image signal, comprising:

• generating a window sequence information for windowing an audio or image signal, the window sequence information indicating a first window function for generating a first frame of spectral values, a second window function and one or more third window functions for generating a second frame of spectral values comprising a first frame portion of spectral values and a second frame portion of spectral values, wherein the first window function, the second window function and the one or more third window functions overlap within a multi-overlap region, and wherein a second overlap portion of the first window function and a first overlap portion of the one or more third window functions extend into each other in the multi-overlap region having a non-zero length, and wherein the second overlap portion of the first window function is longer than the first overlap portion of the one or more third window functions;
• windowing a second block of samples corresponding to the second window function and the one or more third window functions using an auxiliary window function to acquire a second block of windowed samples,
• preprocessing the second block of windowed samples using a folding-in operation of a portion of the second block of windowed samples overlapping with a first block of samples corresponding to the first window function into the multi-overlap region to acquire a preprocessed second block of windowed samples comprising a modified multi-overlap region;
• acquiring the first frame of spectral values;
• acquiring the first frame portion of spectral values of the second frame of spectral values;
• and acquiring the second frame portion of spectral values of the second frame of spectral values;
• and
• processing the first frame of spectral values and the second frame of spectral values to acquire encoded frames of the audio or image signal.

A method for decoding an encoded audio or image signal, comprising an encoded first frame and an encoded second frame, comprising:

• processing the first encoded frame and the second encoded frame to acquire a first frame of spectral values and a second frame of spectral values, the first and second frames of spectral values comprising an aliasing portion, and the second frame of spectral values comprising a first frame portion of spectral values and a second frame portion of spectral values;
• applying a transform to the first frame of spectral values using a first window function to acquire a first block of samples;
• applying another transform to the first frame portion of spectral values of the second frame of spectral values using a second window function;
• applying further one or more transforms to the second frame portion of spectral values of the second frame of spectral values using one or more third window functions,
• wherein the applying the another transform and the applying the further one or more transforms generates a second block of samples,
• wherein the first window function, the second window function and the one or more third window functions form a multi-overlap region, and wherein a second overlap portion of the first window function and a first overlap portion of the one or more third window functions extend into each other in the multi-overlap region having a non-zero length, and wherein the second overlap portion of the first window function is longer than the first overlap portion of the one or more third window function;
• acquiring a post-processed second block of samples comprising a portion of the second block of samples overlapping with the first block of samples in the multi-overlap region;
• and
• overlap-adding a windowed post-processed second block of samples and the first block of samples to acquire a decoded audio or image signal.

A non-transitory digital storage medium having stored thereon a computer program for performing, when running on a computer or a processor, a method for generating an encoded audio or image signal, comprising:

• generating a window sequence information for windowing an audio or image signal, the window sequence information indicating a first window function for generating a first frame of spectral values, a second window function and one or more third window functions for generating a second frame of spectral values comprising a first frame portion of spectral values and a second frame portion of spectral values, wherein the first window function, the second window function and the one or more third window functions overlap within a multi-overlap region, and wherein a second overlap portion of the first window function and a first overlap portion of the one or more third window functions extend into each other in the multi-overlap region having a non-zero length, and wherein the second overlap portion of the first window function is longer than the first overlap portion of the one or more third window functions;
• windowing a second block of samples corresponding to the second window function and the one or more third window functions using an auxiliary window function to acquire a second block of windowed samples,
• preprocessing the second block of windowed samples using a folding-in operation of a portion of the second block of windowed samples overlapping with a first block of samples corresponding to the first window function into the multi-overlap region to acquire a preprocessed second block of windowed samples comprising a modified multi-overlap region;
• acquiring the first frame of spectral values;
• acquiring the first frame portion of spectral values of the second frame of spectral values;
• and acquiring the second frame portion of spectral values of the second frame of spectral values;
• and
• processing the first frame of spectral values and the second frame of spectral values to acquire encoded frames of the audio or image signal,
• when the program is run by a computer.

A non-transitory digital storage medium having stored thereon a computer program for performing, when running on a computer or a processor, a method for decoding an encoded audio or image signal, comprising an encoded first frame and an encoded second frame, comprising:

• processing the first encoded frame and the second encoded frame to acquire a first frame of spectral values and a second frame of spectral values, the first and second frames of spectral values comprising an aliasing portion, and the second frame of spectral values comprising a first frame portion of spectral values and a second frame portion of spectral values;
• applying a transform to the first frame of spectral values using a first window function to acquire a first block of samples;
• applying another transform to the first frame portion of spectral values of the second frame of spectral values using a second window function;
• applying further one or more transforms to the second frame portion of spectral values of the second frame of spectral values using one or more third window functions,
• wherein the applying the another transform and the applying the further one or more transforms generates a second block of samples,
• wherein the first window function, the second window function and the one or more third window functions form a multi-overlap region, and wherein a second overlap portion of the first window function and a first overlap portion of the one or more third window functions extend into each other in the multi-overlap region having a non-zero length, and wherein the second overlap portion of the first window function is longer than the first overlap portion of the one or more third window function;
• acquiring a post-processed second block of samples comprising a portion of the second block of samples overlapping with the first block of samples in the multi-overlap region;
• and
• overlap-adding a windowed post-processed second block of samples and the first block of samples to acquire a decoded audio or image signal,
• when the program is run by a computer.