Concept for encoding an audio signal and decoding an audio signal using speech related spectral shaping information

A decoder for decoding a received signal comprising information related to prediction coefficients, the decoder comprising

• a formant information calculator configured for calculating a speech related spectral shaping information from the prediction coefficients;
• a noise generator configured for generating a decoding noise-like signal;
• a shaper configured for shaping a spectrum of the decoding noise-like signal using the spectral shaping information to acquire a shaped spectrum of the decoding noise-like signal;
• a synthesizer configured for synthesizing a synthesized signal from the shaped spectrum of the decoding noise-like signal and the prediction coefficients;
• and
• a variable amplifier configured for receiving a gain parameter and for amplifying the shaped spectrum of the decoding noise-like signal to obtain an amplified shaped decoding noise-like signal;
• wherein one or more of the formant information calculator, the noise generator, the shaper and the synthesizer is implemented, at least in part, by one or more hardware elements of the decoder;
• wherein the shaper is configured for combining a spectrum of the decoding noise-like signal or a spectrum derived thereof and a transfer function comprising
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• wherein A(z) corresponds to a filter polynomial of the prediction coefficients weighted by weighting scalar factors w1 or w2, wherein the weighting factor w1 of the shaping processor comprises a positive non zero scalar value of at most 1.0 and wherein the weighting factor w2 comprises a positive non zero scalar value of at most 1.00, wherein w2 is greater than w1.

A method for encoding an audio signal, comprising

• deriving, using an analyzer, prediction coefficients and a residual signal from an audio signal frame;
• calculating, using a formant information calculator, a speech related spectral shaping information from the prediction coefficients;
• calculating, using a gain parameter calculator, a gain parameter from an unvoiced residual signal and the spectral shaping information;
• and
• forming, using a bitstream former, an output signal based on an information related to a voiced signal frame, the gain parameter or a quantized gain parameter and the prediction coefficients;
• and
• generating an encoding noise-like signal, comprising:
• shaping a spectrum of the encoding noise-like signal using the speech related spectral shaping information;
• and
• amplifying the shaped spectrum of the encoding noise-like signal to obtain an amplified shaped encoding noise-like signal;
• calculating a gain parameter based on the amplified shaped encoding noise-like signal;
• wherein one or more of the analyzer, the formant information calculator, the gain parameter calculator and the bitstream former is implemented, at least in part, by one or more hardware elements;
• combining a spectrum of the encoding noise-like signal or a spectrum derived thereof and a transfer function comprising
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• wherein A(z) corresponds to a filter polynomial of the prediction coefficients weighted by weighting scalar factors w1 or w2, wherein the weighting factor w1 of the shaping processor comprises a positive non zero scalar value of at most 1.0 and wherein the weighting factor w2 comprises a positive non zero scalar value of at most 1.00, wherein w2 is greater than w1.

A method for decoding a received audio signal comprising an information related prediction coefficients and a gain parameter, the method comprising

• calculating, using a formant information calculator, a speech related spectral shaping information from the prediction coefficients;
• generating, using a noise generator, a decoding noise-like signal;
• shaping, using a shaper, a spectrum of the decoding noise-like signal using the spectral shaping information to acquire a shaped decoding noise-like signal;
• receiving a gain parameter and amplifying the shaped spectrum of the decoding noise-like signal with a variable amplifier, to obtain an amplified spectrum of the shaped noise signal;
• and
• synthesizing, using a synthesizer, a synthesized signal from the amplified shaped decoding noise-like signal and the prediction coefficients;
• wherein one or more of the formant information calculator, the noise generator, the shaper and the synthesizer is implemented, at least in part, by one or more hardware elements;
• combining a spectrum of the decoding noise-like signal or a spectrum derived thereof and a transfer function comprising
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• ⁡
• (
• z
• )
• =
• A
• ⁡
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• z
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• A
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• w
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• wherein A(z) corresponds to a filter polynomial of the prediction coefficients weighted by weighting scalar factors w1 or w2, wherein the weighting factor w1 of the shaping processor comprises a positive non zero scalar value of at most 1.0 and wherein the weighting factor w2 comprises a positive non zero scalar value of at most 1.00, wherein w2 is greater than w1.

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

• an analyzer configured for deriving prediction coefficients and a residual signal from a frame of the audio signal;
• a formant information calculator configured for calculating a speech related spectral shaping information from the prediction coefficients;
• a gain parameter calculator configured for calculating a gain parameter from an unvoiced residual signal and the spectral shaping information;
• and
• a bitstream former configured for forming an output signal based on an information related to a voiced signal frame, the gain parameter or a quantized gain parameter and the prediction coefficients;
• wherein the gain parameter calculator comprises a noise generator configured for generating an encoding noise-like signal;
• and
• wherein the gain parameter calculator comprises a shaping processor configured for spectral shaping the encoding noise-like signal using the speech related spectral shaping information and a variable amplifier configured for amplifying the spectrally shaped encoding noise-like signal to obtain an amplified shaped encoding noise-like signal and a controller for calculating the gain parameter based on the amplified shaped encoding noise-like signal;
• wherein one or more of the analyzer, the formant information calculator, the gain parameter calculator and the bitstream former is implemented, at least in part, by one or more hardware elements of the encoder;
• wherein the gain parameter calculator comprises a comparer configured for comparing the unvoiced residual signal and the amplified shaped encoding noise-like signal to obtain a comparison result, wherein the controller is configured for determining the gain parameter based on the comparison result.

A method for encoding an audio signal, comprising

• deriving, using an analyzer, prediction coefficients and a residual signal from an audio signal frame;
• calculating, using a formant information calculator, a speech related spectral shaping information from the prediction coefficients;
• calculating, using a gain parameter calculator, a gain parameter from an unvoiced residual signal and the spectral shaping information;
• and
• forming, using a bitstream former, an output signal based on an information related to a voiced signal frame, the gain parameter or a quantized gain parameter and the prediction coefficients;
• generating an encoding noise-like signal, comprising:
• shaping a spectrum of the encoding noise-like signal using the speech related spectral shaping information;
• and
• amplifying the spectrally shaped encoding noise-like signal to obtain an amplified shaped encoding noise-like signal;
• calculating a gain parameter based on the amplified shaped encoding noise-like signal;
• wherein one or more of the analyzer, the formant information calculator, the gain parameter calculator and the bitstream former is implemented, at least in part, by one or more hardware elements;
• comparing, using a comparer, the unvoiced residual signal and the amplified shaped encoding noise-like signal to obtain a comparison result, wherein the gain parameter is determined based on the comparison result.

A decoder for decoding a received signal comprising information related to prediction coefficients, the decoder comprising

• a formant information calculator configured for calculating a speech related spectral shaping information from the prediction coefficients;
• a noise generator configured for generating a decoding noise-like signal;
• a shaper configured for shaping a spectrum of the decoding noise-like signal using the spectral shaping information to acquire a spectrally shaped decoding noise-like signal;
• a synthesizer configured for synthesizing a synthesized signal from the spectrally shaped decoding noise-like signal and the prediction coefficients;
• and
• a variable amplifier configured for receiving a gain parameter and for amplifying the spectrally shaped decoding noise-like signal to obtain an amplified shaped decoding noise-like signal;
• wherein one or more of the formant information calculator, the noise generator, the shaper and the synthesizer is implemented, at least in part, by one or more hardware elements of the decoder;
• and
• wherein the gain parameter is generated by a gain parameter calculator comprising:
• a comparer configured for comparing the unvoiced residual signal and the amplified shaped decoding noise-like signal to obtain a comparison result, wherein the gain parameter is determined based on the comparison result.

A method for decoding a received audio signal comprising an information related prediction coefficients and a gain parameter, the method comprising

• calculating, using a formant information calculator, a speech related spectral shaping information from the prediction coefficients;
• generating, using a noise generator, a decoding noise-like signal;
• shaping, using a shaper, a spectrum of the decoding noise-like signal using the spectral shaping information to acquire a spectrally shaped decoding noise-like signal;
• receiving a gain parameter and amplifying the spectrally shaped decoding noise-like signal with a variable amplifier, to obtain an amplified shaped decoding noise signal;
• and
• synthesizing, using a synthesizer, a synthesized signal from the amplified shaped decoding noise-like signal and the prediction coefficients;
• wherein one or more of the formant information calculator, the noise generator, the shaper and the synthesizer is implemented, at least in part, by one or more hardware elements;
• and
• wherein the gain parameter is determined by comparing, using a comparer, the unvoiced residual signal and the amplified shaped decoding noise-like signal to obtain a comparison result, wherein the gain parameter is determined based on the comparison result.