Fraunhofer-Gesellschaft Zur Foerderung Der Angewandten Forschung E.v.

Franz Reutelhuber

Markus Multrus

Eleni Fotopoulou

Jan Büthe

Guillaume Fuchs

Sascha Disch

Srikanth Korse

Stefan Döhla

Jan Buethe

Pallavi Maben

Juergen Herre

Ralf Geiger

Bernd Edler

Emmanuel Ravelli

Wolfgang Jaegers

Stefan Bayer

Martin Dietz

Jürgen Herre

Florin Ghido

Alexander Adami

Stefan Doehla

Goran Markovic

Jan Frederik Kiene

Wolfgang Jagers

Wolfgang JÄGERS

An audio quantizer for quantizing a plurality of audio information items has: a first stage vector quantizer for quantizing the plurality of audio information items to determine a first stage vector quantization result and a plurality of intermediate quantized items corresponding to the first stage vector quantization result; a residual item determiner for calculating a plurality of residual items from the plurality of intermediate quantized items and the plurality of audio information items; and a second stage vector quantizer for quantizing the plurality of residual items to obtain a second stage vector quantization result, wherein the first stage vector quantization result and the second stage vector quantization result are a quantized representation of the plurality of audio information items.

Audio quantizer and audio dequantizer and related methods

An apparatus for generating an output downmix representation from an input downmix representation, wherein at least a portion of the input downmix representation is in accordance with a first downmixing scheme, includes: an upmixer for upmixing at least the portion of the input downmix representation using an upmixing scheme corresponding to the first downmixing scheme to obtain at least one upmixed portion; and a downmixer for downmixing the at least one upmixed portion in accordance with a second downmixing scheme different from the first downmixing scheme.

Apparatus, method or computer program for generating an output downmix representation

Apparatus for processing an audio scene representing a sound field, the audio scene having information on a transport signal and a first set of parameters. The apparatus has a parameter processor for processing the first set of parameters to obtain a second set of parameters, wherein the parameter processor is configured to calculate at least one raw parameter for each output time frame using at least one parameter of the first set of parameters for the input time frame, to calculate a smoothing information such as a factor for each raw parameter in accordance with a smoothing rule, and to apply a corresponding smoothing information to the corresponding raw parameter to derive the parameter of the second set of parameters for the output time frame. The apparatus further has an output interface for generating a processed audio scene using the second set of parameters and the information on the transport signal.

Apparatus, method, or computer program for processing an encoded audio scene using a parameter smoothing

Apparatus for processing an audio scene representing a sound field, the audio scene comprising information on a transport signal and a set of parameters. The apparatus comprising an output interface for generating a processed audio scene using the set of parameters and the information on the transport signal, wherein the output interface is configured to generate a raw representation of two or more channels using the set of parameters and the transport signal and a multichannel enhancer for generating an enhancement representation of the two or more channels using the transport signal, and a signal combiner for combining the raw representation of the two or more channels and the enhancement representation of the two or more channels to obtain the processed audio scene.

Apparatus, method, or computer program for processing an encoded audio scene using a bandwidth extension

An apparatus for decoding an encoded multichannel signal includes: a base channel decoder for decoding an encoded base channel to acquire a decoded base channel; a decorrelation filter for filtering at least a portion of the decoded base channel to acquire a filling signal; and a multichannel processor for performing a multichannel processing using a spectral representation of the decoded base channel and a spectral representation of the filling signal, wherein the decorrelation filter is a broad band filter and the multichannel processor is configured to apply a narrow band processing to the spectral representation of the decoded base channel and the spectral representation of the filling signal.

Apparatus for encoding or decoding an encoded multichannel signal using a filling signal generated by a broad band filter

In multichannel audio coding, improved computational efficiency is achieved by computing comparison parameters for ITD compensation between any two channels in the frequency domain for a parametric audio encoder. This may mitigate negative effects on encoder parameter estimates.

Multichannel audio coding

An apparatus for encoding a multi-channel signal having at least two channels, has: a downmixer for calculating a downmix signal from the multi-channel signal; a parameter calculator for calculating a side gain from a first channel of the at least two channels and a second channel of the at least two channels and for calculating a residual gain from the first channel and the second channel; and an output interface for generating an output signal, the output signal having information on the downmix signal, and on the side gain and the residual gain.

Apparatus and method for encoding or decoding a multichannel signal using a side gain and a residual gain

A downmixer for downmixing a multi-channel signal having at least two channels, includes: a weighting value estimator for estimating band-wise weighting values for the at least two channels; a spectral weighter for weighting spectral domain representations of the at least two channels using the band-wise weighting values; a converter for converting weighted spectral domain representations of the at least two channels into time representations of the at least two channels; and a mixer for mixing the time representations of the at least two channels to obtain a downmix signal.

Downmixer and method of downmixing

An apparatus for estimating an inter-channel time difference between a first channel signal and a second channel signal, includes a signal analyzer for estimating a signal characteristic of the first channel signal or the second channel signal or both signals or a signal derived from the first channel signal or the second channel signal; a calculator for calculating a cross-correlation spectrum for a time block from the first channel signal in the time block and the second channel signal in the time block; a weighter for weighting a smoothed or non-smoothed cross-correlation spectrum to obtain a weighted cross correlation spectrum using a first weighting procedure or using a second weighting procedure depending on a signal characteristic estimated by the signal analyzer, wherein the first weighting procedure is different from the second weighting procedure; and a processor for processing the weighted cross-correlation spectrum to obtain the inter-channel time difference.

Apparatus, method or computer program for estimating an inter-channel time difference

An apparatus for downmixing a multi-channel signal having at least two channels, has: a downmixer for calculating a downmix signal from the multi-channel signal, wherein the downmixer is configured to calculate the downmix using an absolute phase compensation, so that a channel having a lower energy among the at least two channels is only rotated or is rotated stronger than a channel having a greater energy in calculating the downmix signal; and an output interface for generating an output signal, the output signal having information on the downmix signal.

Apparatus and method for downmixing or upmixing a multichannel signal using phase compensation

An apparatus for encoding an audio signal includes: a core encoder for core encoding first audio data in a first spectral band; a parametric coder for parametrically coding second audio data in a second spectral band being different from the first spectral band, wherein the parametric coder includes: an analyzer for analyzing first audio data in the first spectral band to obtain a first analysis result and for analyzing second audio data in the second spectral band to obtain a second analysis result; a compensator for calculating a compensation value using the first analysis result and the second analysis result; and a parameter calculated for calculating a parameter from the second audio data in the second spectral band using the compensation value.

Apparatus and method for encoding an audio signal using an output interface for outputting a parameter calculated from a compensation value

An apparatus for decoding an encoded multichannel signal includes: a base channel decoder for decoding an encoded base channel to obtain a decoded base channel; a decorrelation filter for filtering at least a portion of the decoded base channel to obtain a filling signal; and a multichannel processor for performing a multichannel processing using a spectral representation of the decoded base channel and a spectral representation of the filling signal, wherein the decorrelation filter is a broad band filter and the multichannel processor is configured to apply a narrow band processing to the spectral representation of the decoded base channel and the spectral representation of the filling signal.

Growing community of inventors

Erlangen, Germany

Franz Reutelhuber