Frequency-domain audio coding supporting transform length switching

Frequency-domain audio encoder supporting transform length switching, comprising

• a transformer configured to subject time-domain portions of an audio signal to transformation to acquire frequency-domain coefficients of frames of the audio signal;
• an inverse scaler configured to inversely scale the frequency-domain coefficients according to scale factors;
• a frequency-domain coefficient inserter configured to insert the frequency-domain coefficients of the frames of the audio signal, inversely scaled according to scale factors, into the data stream;
• and
• a scale factor inserter configured to insert scale factors into the data stream,
• wherein the transformer is configured to switch for the frames of the audio signals at least between
• performing one transform of a first transform length for a respective frame, and
• performing more than one transform of a second transform length, shorter than the first transform length, for the respective frame,
• wherein the transformer is further configured to signal the switching by a signalization within the frames of the data stream;
• wherein the frequency-domain coefficient inserter is configured to insert, for a respective frame, a sequence of the frequency-domain coefficients of the respective frame of the audio signal, inversely scaled according to scale factors, into the data stream in a manner independent from the signalization, with, depending on the signalization, the sequence of frequency-domain coefficients formed by
• sequentially arranging the frequency-domain coefficients of the one transform of a respective frame in a non-interleaved manner in case of one transform performed for the respective frame, and
• by interleaving the frequency-domain coefficients of the more than one transform of the respective frame in case of more than one transform performed for the respective frame,
• wherein the scale factor inserter operates independent from the signalization.

Method for frequency-domain audio decoding supporting transform length switching, comprising

• extracting frequency-domain coefficients of frames of an audio signal from a data stream;
• extracting scale factors from the data stream;
• subjecting the frequency-domain coefficients of the frames, scaled according to scale factors, to inverse transformation to acquire time-domain portions of the audio signal;
• combining the time-domain portions to acquire the audio signal,
• wherein the subjection to inverse transformation is responsive to a signalization within the frames of the audio signal so as to, depending on the signalization, comprise
• forming one transform by sequentially arranging the frequency-domain coefficients of a respective frame in a non-de-interleaved manner and subjecting the one transform to an inverse transformation of a first transform length, or
• forming more than one transform by de-interleaving the frequency-domain coefficients of the respective frame and subjecting each of the more than one transforms to an inverse transformation of a second transform length, shorter than the first transform length,
• wherein the extraction of the frequency-domain coefficients and the extraction of the scale factors are independent from the signalization.

Method for frequency-domain audio encoding supporting transform length switching, comprising

• subjecting time-domain portions of an audio signal to transformation to acquire frequency-domain coefficients of frames of the audio signal;
• inversely scaling the frequency-domain coefficients according to scale factors;
• inserting the frequency-domain coefficients of the frames of the audio signal, inversely scaled according to scale factors, into the data stream;
• and
• inserting scale factors into the data stream,
• wherein the subjection to transformation switches for the frames of the audio signal at least between
• performing one transform of a first transform length for a respective frame, and
• performing more than one transform of a second transform length, shorter than the first transform length, for the respective frame,
• wherein the method comprises signaling the switching by a signalization within the frames of the data stream;
• wherein the insertion of the frequency-domain coefficients is performed by inserting, for a respective frame, a sequence of the frequency-domain coefficients of the respective frame of the audio signal, inversely scaled according to scale factors, into the data stream in a manner independent from the signalization, with, depending on the signalization, the sequence of frequency-domain coefficients formed by
• sequentially arranging the frequency-domain coefficients of the one transform of the respective frame in a non-interleaved manner in case of one transform performed for the respective frame, and
• by interleaving the frequency-domain coefficients of the more than one transform of the respective frame in case of more than one transform performed for the respective frame,
• wherein the insertion of scale factors is performed independent from the signalization.

A non-transitory digital storage medium having a computer program stored thereon to perform the method for frequency-domain audio decoding supporting transform length switching, said method comprising:

• extracting frequency-domain coefficients of frames of an audio signal from a data stream;
• extracting scale factors from the data stream;
• subjecting the frequency-domain coefficients of the frames, scaled according to scale factors, to inverse transformation to acquire time-domain portions of the audio signal;
• combining the time-domain portions to acquire the audio signal,
• wherein the subjection to inverse transformation is responsive to a signalization within the frames of the audio signal so as to, depending on the signalization, comprise
• forming one transform by sequentially arranging the frequency-domain coefficients of a respective frame in a non-de-interleaved manner and subjecting the one transform to an inverse transformation of a first transform length, or
• forming more than one transform by de-interleaving the frequency-domain coefficients of the respective frame and subjecting each of the more than one transforms to an inverse transformation of a second transform length, shorter than the first transform length,
• wherein the extraction of the frequency-domain coefficients and the extraction of the scale factors are independent from the signalization,
• when said computer program is run by a computer.

A non-transitory digital storage medium having a computer program stored thereon to perform the method for frequency-domain audio encoding supporting transform length switching, said method comprising:

• subjecting time-domain portions of an audio signal to transformation to acquire frequency-domain coefficients of frames of the audio signal;
• inversely scaling the frequency-domain coefficients according to scale factors;
• inserting the frequency-domain coefficients of the frames of the audio signal, inversely scaled according to scale factors, into the data stream;
• and
• inserting scale factors into the data stream,
• wherein the subjection to transformation switches for the frames of the audio signal at least between
• performing one transform of a first transform length for a respective frame, and
• performing more than one transform of a second transform length, shorter than the first transform length, for the respective frame,
• wherein the method comprises signaling the switching by a signalization within the frames of the data stream;
• wherein the insertion of the frequency-domain coefficients is performed by inserting, for a respective frame, a sequence of the frequency-domain coefficients of the respective frame of the audio signal, inversely scaled according to scale factors, into the data stream in a manner independent from the signalization, with, depending on the signalization, the sequence of frequency-domain coefficients formed by
• sequentially arranging the frequency-domain coefficients of the one transform of the respective frame in a non-interleaved manner in case of one transform performed for the respective frame, and
• by interleaving the frequency-domain coefficients of the more than one transform of the respective frame in case of more than one transform performed for the respective frame,
• wherein the insertion of scale factors is performed independent from the signalization,
• when said computer program is run by a computer.