Audio encoder for encoding a multichannel signal and audio decoder for decoding an encoded audio signal

An audio decoder for decoding an encoded audio signal comprising a core encoded signal, bandwidth extension parameters, and multichannel information, the audio decoder comprising:

• a linear prediction domain core decoder for decoding the core encoded signal to generate a mono signal;
• an analysis filterbank to convert the mono signal into a spectral representation;
• a multichannel decoder for generating a first channel spectrum and a second channel spectrum from the spectral representation of the mono signal and the multichannel information;
• and
• a synthesis filterbank processor for synthesis filtering the first channel spectrum to acquire a first channel signal and for synthesis filtering the second channel spectrum to acquire a second channel signal,
• wherein the linear prediction domain core decoder comprises an Algebraic Code-Excited Linear Prediction (ACELP) decoder and a time domain bandwidth extension processor.

A method for encoding a multichannel signal, the method comprising:

• downmixing the multichannel signal to acquire a downmix signal,
• encoding the downmix signal, wherein the downmix signal comprises a low band and a high band, wherein the encoding the downmix signal is comprises applying a bandwidth extension processing for parametrically encoding the high band;
• generating a spectral representation of the multichannel signal;
• and
• processing the spectral representation comprising the low band and the high band of the multichannel signal to generate multichannel information,
• wherein the encoding the downmix signal comprises an Algebraic Code-Excited Linear Prediction (ACELP) processing and wherein the bandwidth extension processing comprises a time domain bandwidth extension processing.

A method of decoding an encoded audio signal, comprising a core encoded signal, bandwidth extension parameters, and multichannel information, the method comprising

• decoding the core encoded signal to generate a mono signal;
• converting the mono signal into a spectral representation;
• generating a first channel spectrum and a second channel spectrum from the spectral representation of the mono signal and the multichannel information;
• and
• synthesis filtering the first channel spectrum to acquire a first channel signal and synthesis filtering the second channel spectrum to acquire a second channel signal,
• wherein the decoding the core encoded signal comprises an Algebraic Code-Excited Linear Prediction (ACELP) decoding and a time domain bandwidth extension processing.

A non-transitory digital storage medium having a computer program stored thereon to perform the method for encoding a multichannel signal, the method comprising:

• downmixing the multichannel signal to acquire a downmix signal,
• encoding the downmix signal, wherein the downmix signal comprises a low band and a high band, wherein encoder the encoding the downmix signal comprises applying a bandwidth extension processing for parametrically encoding the high band;
• generating a spectral representation of the multichannel signal;
• and
• processing the spectral representation comprising the low band and the high band of the multichannel signal to generate multichannel information,
• wherein the encoding the downmix signal comprises an Algebraic Code-Excited Linear Prediction (ACELP) processing and wherein the bandwidth extension processing comprises a time domain bandwidth extension processing,
• 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 of decoding an encoded audio signal, comprising a core encoded signal, bandwidth extension parameters, and multichannel information, the method comprising:

• decoding the core encoded signal to generate a mono signal;
• converting the mono signal into a spectral representation;
• generating a first channel spectrum and a second channel spectrum from the spectral representation of the mono signal and the multichannel information;
• and
• synthesis filtering the first channel spectrum to acquire a first channel signal and synthesis filtering the second channel spectrum to acquire a second channel signal,
• wherein the decoding the core encoded signal comprises an Algebraic Code- Excited Linear Prediction (ACELP) decoding and a time domain bandwidth extension processing,
• when said computer program is run by a computer.