Spatial audio

Decoding apparatus for decoding an encoded digital audio signal comprising at least a first sand a second digital audio signal component, which have been encoded into a composite digital signal (X) and a parameter signal (P), the decoding apparatus comprising:

• an input unit for receiving a transmission signal,
• a demultiplexer unit for retrieving the composite digital signal and the parameter signal from the transmission signal,
• a conversion unit for receiving the composite digital signal and the parameter signal to generate a replica of the first and second digital audio signal component therefrom, and
• wherein the parameter signal is a measure of the similarity of waveforms of the replicas of the at least first and second digital audio signal components, said measure of similarity corresponding to a value of a cross correlation function between the replicas of said at least first and second digital audio signal components, said value being substantially equal to the maximum of said cross correlation function.

A method of encoding an audio signal, the method comprising:

• generating a monaural signal comprising a combination of at least two input audio channels,
• determining a set of spatial parameters indicative of spatial properties of the at least two input audio channels, the set of spatial parameters including a parameter representing a measure of similarity of waveforms of the at least two input audio channels, and
• generating an encoded signal comprising the monaural signal and the set of spatial parameters, and
• wherein the measure of similarity corresponds to a value of a cross-correlation function at a maximum of said cross-correlation function.

An encoder for encoding an audio signal, the encoder comprising:

• means for generating a monaural signal comprising a combination of at least two input audio channels,
• means for determining a set of spatial parameters indicative of spatial properties of the at least two input audio channels, the set of spatial parameters including a parameter representing a measure of similarity of waveforms of the at least two input audio channels, and
• means for generating an encoded signal comprising the monaural signal and the set of spatial parameters, and
• wherein the measure of similarity corresponds to a value of a cross-correlation function at a maximum of said cross-correlation function.

A method of decoding an encoded audio signal, the method comprising:

• obtaining a monaural signal from the encoded audio signal, the monaural signal comprising a combination of at least two audio channels,
• obtaining a set of spatial parameters from the encoded audio signal, and
• generating a multi-channel output signal from the monaural signal and the spatial parameters, the set of spatial parameters including a parameter representing a measure of similarity of waveforms of the multi-channel output signal, and
• wherein the measure of similarity corresponds to a value of a cross-correlation function at a maximum of said cross-correlation function of the multi-channel output signal.

A decoder for decoding an encoded audio signal, the decoder comprising

• means for obtaining a monaural signal from the encoded audio signal, the monaural signal comprising a combination of at least two audio channels, and
• means for obtaining a set of spatial parameters from the encoded audio signal, and
• means for generating a multi-channel output signal from the monaural signal and the spatial parameters, the set of spatial parameters including a parameter representing a measure of similarity of waveforms of the multi-channel output signal, and
• wherein the measure of similarity corresponds to a value of a cross-correlation function at a maximum of said cross-correlation function of the multi-channel output signal.

A non-transitive computer readable media comprising a program that when loaded into an audio signal encoder controls a processor to perform the method comprising:

• generating a monaural signal comprising a combination of at least two input audio channels,
• determining a set of spatial parameters indicative of spatial properties of the at least two input audio channels, the set of spatial parameters including a parameter representing a measure of similarity of waveforms of the at least two input audio channels, and
• generating an encoded signal comprising the monaural signal and the set of spatial parameters, and
• wherein the measure of similarity corresponds to a value of a cross-correlation function at a maximum of said cross-correlation function.

A non-transitive computer readable media comprising a program that when loaded into an audio signal decoder controls a processor to perform the method comprising:

• obtaining a monaural signal from the encoded audio signal, the monaural signal comprising a combination of at least two audio channels,
• obtaining a set of spatial parameters from the encoded audio signal, and
• generating a multi-channel output signal from the monaural signal and the spatial parameters, the set of spatial parameters including a parameter representing a measure of similarity of waveforms of the multi-channel output signal, and
• wherein the measure of similarity corresponds to a value of a cross-correlation function at a maximum of said cross-correlation function of the multi-channel output signal.

An encoder for encoding an audio signal, the encoder comprising:

• a first multiplexer unit that generates a monaural signal comprising a combination of at least two input audio channels of the audio signal,
• a parameter generator unit that determines a set of spatial parameters indicative of spatial properties of the at least two input audio channels, the set of spatial parameters including a parameter representing a measure of similarity of waveforms of the at least two input audio channels, and
• a second multiplexor unit that generates an encoded signal comprising the monaural signal and the set of spatial parameters, and
• wherein the measure of similarity corresponds to a value of a cross-correlation function at a maximum of said cross-correlation function.