Device and method for generating a complex spectral representation of a discrete-time signal

A method for generating a complex audio spectral representation of a discrete-time audio signal, comprising the steps of:

• generating a block-wise real-valued audio spectral representation of the discrete-time audio signal, the audio spectral representation comprising temporally successive blocks, each block comprising a set of real audio spectral coefficients;
• and
• post-processing the block-wise real-valued audio spectral representation to obtain a block-wise complex approximated audio spectral representation comprising successive blocks wherein the complex approximated audio spectral representation represents the discrete-time audio signal, each block comprising a set of complex approximated audio spectral coefficients, wherein a complex approximated audio spectral coefficient can be represented by a first partial audio spectral coefficient and a second partial audio spectral coefficient, wherein at least one of the first and second partial audio spectral coefficients is to be determined by combining at least two temporally and/or frequency-adjacent real audio spectral coefficients.

A device for generating a real audio spectral representation comprising an audio signal from a complex approximated audio spectral representation comprising an audio signal, the real audio spectral representation to be determined comprising temporally successive blocks, each block comprising a set of real audio spectral coefficients, the complex approximated audio spectral representation comprising temporally successive blocks, each block comprising a set of complex approximated audio spectral coefficients, wherein a complex approximated audio spectral coefficient can be represented by a first partial audio spectral coefficient and a second partial audio spectral coefficient, the complex approximated audio spectral coefficients having been calculated by a transform rule from the real audio spectral coefficients, the transform rule including a combination of at least two temporally and/or frequency-adjacent real audio spectral coefficients to calculate at least one of the first and second partial audio spectral coefficients of a complex approximated audio spectral coefficient, comprising:

• a processor for performing a combining rule inverse to the transform rule to calculate the real audio spectral coefficients from the complex approximated audio spectral coefficients.

A method for generating a real audio spectral representation comprising an audio signal of a complex approximated audio spectral representation comprising an audio signal, the real audio spectral representation to be determined comprising temporally successive blocks, each block comprising a set of real audio spectral coefficients, the complex approximated audio spectral representation comprising temporally successive blocks, each block comprising a set of complex approximated audio spectral coefficients, wherein a complex approximated audio spectral coefficient can be represented by a first partial audio spectral coefficient and a second partial audio spectral coefficient, the complex approximated audio spectral coefficients having been calculated by a transform rule from the real audio spectral coefficients, the transform rule including a combination of at least two temporally and/or frequency-adjacent real audio spectral coefficients to calculate at least one of the first and second partial audio spectral coefficients of a complex approximated audio spectral coefficient, comprising the step of:

• performing a combination rule inverse to the transform rule to calculate the real audio spectral coefficients from the complex approximated audio spectral coefficients.

At A machine-readable carrier having stored thereon least one computer readable medium containing a computer program product comprising program code for performing a method for generating a complex audio spectral representation of a discrete-time audio signal, comprising the steps of:

• generating a block-wise real-valued audio spectral representation of the discrete-time audio signal, the audio spectral representation comprising temporally successive blocks wherein the complex approximated audio spectral representation represents the discrete-time audio signal, each block comprising a set of real audio spectral coefficients;
• and post-processing the block-wise real-valued audio spectral representation to obtain a block-wise complex approximated audio spectral representation comprising successive blocks, each block comprising a set of complex approximated audio spectral coefficients, wherein a complex approximated audio spectral coefficient can be represented by a first partial audio spectral coefficient and a second partial audio spectral coefficient, wherein at least one of the first and second partial audio spectral coefficients is to be determined by combining at least two temporally and/or frequency-adjacent real audio spectral coefficients, when the computer program code runs on a computer.

A machine-readable carrier having stored thereon computer program product comprising program code for performing a method for coding a discrete-time audio signal, comprising the steps of:

• generating a block-wise real-valued audio spectral representation of the discrete-time audio signal, the audio spectral representation comprising temporally successive blocks, each block comprising a set of real audio spectral coefficients;
• calculating a psycho-acoustic masking threshold depending on the discrete-time signal;
• quantizing a block of real-valued audio spectral coefficients using the psycho-acoustic masking threshold, whereby an encoded audio signal is obtained, wherein a step of post-processing the block-wise real audio spectral representation is performed in the step of calculating to obtain a block-wise complex approximated audio spectral representation comprising successive blocks, each comprising a set of complex approximated audio spectral coefficients, wherein a complex approximated audio spectral coefficient can be represented by a first partial audio spectral coefficient and a second partial audio spectral coefficient, wherein at least one of the first and second partial audio spectral coefficients is to be determined by combining at least two temporally and/or frequency-adjacent real audio spectral coefficients, when the computer program code runs on a computer.