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

Emmanuel Ravelli

Guillaume Fuchs

Markus Multrus

Markus Schnell

Martin Dietz

Stefan Doehla

Sascha Disch

Eleni Fotopoulou

Benjamin Schubert

Goran Markovic

Bernhard Grill

Manuel Jander

Wolfgang Jaegers

Ralf Geiger

Christian Helmrich

Stefan Bayer

Matthias Neusinger

Grzegorz Pietrzyk

Christian Neukam

Conrad Benndorf

Konstantin Schmidt

Andreas Niedermeier

Adrian Tomasek

Pallavi Maben

Stefan Geyersberger

Manfred Lutzky

Tom Baeckstroem

Srikanth Korse

Anthony Lombard

Stefan Döhla

Stefan Reuschl

Alexander Tschekalinskij

Jérémie Lecomte

Juergen Herre

Jürgen Herre

Marc Gayer

Franz Reutelhuber

Michael Schnabel

Jan Büthe

Tom Backstrom

Ralph Sperschneider

Panji Setiawan

Stephan Wilde

Tobias Albert

Vesa Ruoppila

Arthur Tritthart

Tom Bäckström

Jan Frederik Kiene

Tom BÄCKSTRÖM

Wolfgang JÄGERS

Jan Buethe

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 audio decoder for providing a decoded audio representation on the basis of an encoded audio representation includes a filter for providing an enhanced audio representation of the decoded audio representation. The filter is configured to obtain a plurality of scaling values, which are associated with different frequency bins or frequency ranges, on the basis of spectral values of the decoded audio representation which are associated with different frequency bins or frequency ranges, and the filter is configured to scale spectral values of the decoded audio signal representation, or a pre-processed version thereof, using the scaling values, to obtain the enhanced audio representation. An apparatus for determining a set of values defining characteristics of a filter for providing an enhanced audio representation on the basis of a decoded audio representation is also described.

Audio decoder, apparatus for determining a set of values defining characteristics of a filter, methods for providing a decoded audio representation, methods for determining a set of values defining characteristics of a filter and computer program

An audio decoder for providing a decoded audio information on the basis of an encoded audio information includes a linear-prediction-domain decoder configured to provide a first decoded audio information on the basis of an audio frame encoded in a linear prediction domain, a frequency domain decoder configured to provide a second decoded audio information on the basis of an audio frame encoded in a frequency domain, and a transition processor. The transition processor is configured to obtain a zero-input-response of a linear predictive filtering, wherein an initial state of the linear predictive filtering is defined depending on the first decoded audio information and the second decoded audio information, and modify the second decoded audio information depending on the zero-input-response, to obtain a smooth transition between the first and the modified second decoded audio information.

Audio decoder, method and computer program using a zero-input-response to obtain a smooth transition

A multi-channel audio encoder for providing an encoded audio representation on the basis of an input audio representation is provided. The multi-channel audio encoder is configured to switch between a parametric multi-channel encoding of a plurality of channels and an individual encoding of a plurality of channels in dependence on characteristics of the input audio representation.

Multi-channel audio encoder, decoder, methods and computer program for switching between a parametric multi-channel operation and an individual channel operation

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 processing an audio signal having associated therewith a pitch lag information and a gain information, includes a domain converter for converting a first domain representation of the audio signal into a second domain representation of the audio signal; and a harmonic post-filter for filtering the second domain representation of the audio signal, wherein the post-filter is based on a transfer function including a numerator and a denominator, wherein the numerator includes a gain value indicated by the gain information, and wherein the denominator includes an integer part of a pitch lag indicated by the pitch lag information and a multi-tap filter depending on a fractional part of the pitch lag.

Apparatus and method for processing an audio signal using a harmonic post-filter

A method is described that processes an audio signal. A discontinuity between a filtered past frame and a filtered current frame of the audio signal is removed using linear predictive filtering.

Method and apparatus for processing an audio signal, audio decoder, and audio encoder to filter a discontinuity by a filter which depends on two fir filters and pitch lag

An audio encoder for encoding an audio signal has: a first encoding processor for encoding a first audio signal portion in a frequency domain, having: a time frequency converter for converting the first audio signal portion into a frequency domain representation; an analyzer for analyzing the frequency domain representation to determine first spectral portions to be encoded with a first spectral resolution and second regions to be encoded with a second resolution; and a spectral encoder for encoding the first spectral portions with the first spectral resolution and encoding the second portions with the second resolution; a second encoding processor for encoding a second different audio signal portion in the time domain; a controller for analyzing and determining, which portion of the audio signal is the first audio signal portion encoded in the frequency domain and which portion is the second audio signal portion encoded in the time domain; and an encoded signal former for forming an encoded audio signal having a first encoded signal portion for the first audio signal portion and a second encoded signal portion for the second portion.

Audio encoder and decoder using a frequency domain processor with full-band gap filling and a time domain processor

A method is described that processes an audio signal. A discontinuity between a filtered past frame and a filtered current frame of the audio signal is removed using linear predictive filter. Removing the discontinuity further comprises processing a beginning portion of the filtered current frame, wherein the beginning portion of the current frame comprises a predefined number of samples being less or equal than a total number of samples in the current frame, and wherein processing the beginning portion of the current frame comprises subtracting a beginning portion of a zero-input-response (ZIR) from the beginning portion of the filtered current frame.

Method and apparatus for processing an audio signal, audio decoder, and audio encoder for removing a discontinuity between frames by subtracting a portion of a zero-input-reponse

An apparatus for encoding audio information is provided. The apparatus for encoding audio information includes a selector for selecting a comfort noise generation mode from two or more comfort noise generation modes depending on a background noise characteristic of an audio input signal, and an encoding unit for encoding the audio information, wherein the audio information includes mode information indicating the selected comfort noise generation mode.

Apparatus and method for comfort noise generation mode selection

A method and an apparatus for synthesizing an audio signal are described. A spectral tilt is applied to the code of a codebook used for synthesizing a current frame of the audio signal. The spectral tilt is based on the spectral tilt of the current frame of the audio signal. Further, an audio decoder operating in accordance with the inventive approach is described.

Apparatus and method for synthesizing an audio signal, decoder, encoder, system and computer program

An apparatus for providing a processed audio signal representation on the basis of input audio signal representation configured to apply an un-windowing, in order to provide the processed audio signal representation on the basis of the input audio signal representation. The apparatus is configured to adapt the un-windowing in dependence on one or more signal characteristics and/or in dependence on one or more processing parameters used for a provision of the input audio signal representation.

Apparatus and audio signal processor, for providing processed audio signal representation, audio decoder, methods and computer programs

Apparatus and audio signal processor, for providing processed audio signal representation, audio decoder, audio encoder, methods and computer programs

Growing community of inventors

Erlangen, Germany

Emmanuel Ravelli