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

Jens Hirschfeld

Gerald Schuller

Stefan Wabnik

Markus Multrus

Juergen Herre

Bernhard Grill

Nikolaus Rettelbach

Guillaume Fuchs

Stefan Geyersberger

Harald Popp

Ulrich Kraemer

Stefan Bayer

Manfred Lutzky

Ralf Geiger

Frederik Nagel

Yoshikazu Yokotani

Sascha Disch

Johannes Hilpert

Max Neuendorf

Jürgen Herre

Wolfgang Fiesel

Ulrich Krämer

Nikolaus Rettlebach

An encoder for providing an audio stream on the basis of a transform-domain representation of an input audio signal includes a quantization error calculator configured to determine a multi-band quantization error over a plurality of frequency bands of the input audio signal for which separate band gain information is available. The encoder also includes an audio stream provider for providing the audio stream such that the audio stream includes information describing an audio content of the frequency bands and information describing the multi-band quantization error. A decoder for providing a decoded representation of an audio signal on the basis of an encoded audio stream representing spectral components of frequency bands of the audio signal includes a noise filler for introducing noise into spectral components of a plurality of frequency bands to which separate frequency band gain information is associated on the basis of a common multi-band noise intensity value.

Audio encoder, audio decoder, methods for encoding and decoding an audio signal, audio stream and a computer program

An encoder provides an audio stream based on a transform-domain representation of an input audio signal and includes a quantization error calculator configured to determine a multi-band quantization error over a plurality of frequency bands of the input audio signal for which separate band gain information is available. The encoder also includes an audio stream provider for providing the audio stream such that the audio stream includes information describing an audio content of the frequency bands and information describing the multi-band quantization error. A decoder provides a decoded representation of an audio signal based on an encoded audio stream representing spectral components of frequency bands of the audio signal and includes a noise filler for introducing noise into spectral components of a plurality of frequency bands to which separate frequency band gain information is associated on the basis of a common multi-band noise intensity value.

An encoder for providing an audio stream on the basis of a transform- domain representation of an input audio signal includes a quantization error calculator configured to determine a multi-band quantization error over a plurality of frequency bands of the input audio signal for which separate band gain information is available. The encoder also includes an audio stream provider for providing the audio stream such that the audio stream includes information describing an audio content of the frequency bands and information describing the multi-band quantization error. A decoder for providing a decoded representation of an audio signal on the basis of an encoded audio stream representing spectral components of frequency bands of the audio signal includes a noise filler for introducing noise into spectral components of a plurality of frequency bands to which separate frequency band gain information is associated on the basis of a common multi-band noise intensity value.

Audio encoder, audio decoder, methods for encoding and decoding an audio signal, and a computer program

A very coarse quantization exceeding the measure determined by the masking threshold without or only very little quality losses is enabled by quantizing not immediately the prefiltered signal, but a prediction error obtained by forward-adaptive prediction of the prefiltered signal. Due to the forward adaptivity, the quantizing error has no negative effect on the prediction on the decoder side.

System, method, and non-transitory computer readable medium storing a program utilizing a postfilter for filtering a prefiltered audio signal in a decoder

Information signal encoding using a forward-adaptive prediction and a backwards-adaptive quantization

A noise filler for providing a noise-filled spectral representation of an audio signal on the basis of an input spectral representation of the audio signal has a spectral region identifier configured to identify spectral regions of the input spectral representation spaced from non-zero spectral regions of the input spectral representation by at least one intermediate spectral region, to obtain identified spectral regions, and a noise inserter configured to selectively introduce noise into the identified spectral regions to obtain the noise-filled spectral representation of the audio signal. A noise filling parameter calculator for providing a noise filling parameter on the basis of a quantized spectral representation of an audio signal has a spectral region identifier, as mentioned above, and a noise value calculator configured to selectively consider quantization errors of the identified spectral regions for a calculation of the noise filling parameter. Accordingly, an encoded audio signal representation representing the audio signal can be obtained.

Noise filer, noise filling parameter calculator encoded audio signal representation, methods and computer program

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Heringen, Germany

Jens Hirschfeld