Dolby International Ab

Tobias R Wagenblass

Karsten Linzmeier

Tobias Friedrich

Claus-Christian Spenger

Alexander Mueller

Christof Fersch

Holger Hoerich

Michael Schug

Heiko Purnhagen

Daniel Homm

The present document relates to audio coding systems. In particular, the present document relates to efficient methods and systems for parametric multi-channel audio coding. An audio encoding system configured to generate a bitstream indicative of a downmix signal and spatial metadata for generating a multi-channel upmix signal from the downmix signal is described. The system comprises a downmix processing unit configured to generate the downmix signal from a multi-channel input signal; wherein the downmix signal comprises m channels and wherein the multi-channel input signal comprises n channels; n, m being integers with m<n. Furthermore, the system comprises a parameter processing unit configured to determine the spatial metadata from the multi-channel input signal. In addition, the system comprises a configuration unit configured to determine one or more control settings for the parameter processing unit based on one or more external settings; wherein the one or more external settings comprise a target data-rate for the bitstream and wherein the one or more control settings comprise a maximum data-rate for the spatial metadata.

Methods for parametric multi-channel encoding

The present document relates to audio coding systems. In particular, the present document relates to efficient methods and systems for parametric multi-channel audio coding. An audio encoding system configured to generate a bitstream indicative of a downmix signal and spatial metadata for generating a multi-channel upmix signal from the downmix signal is described. The system comprises a downmix processing unit configured to generate the downmix signal from a multi-channel input signal; wherein the downmix signal comprises m channels and wherein the multi-channel input signal comprises n channels; n, m being integers with m&#x3c;n. Furthermore, the system comprises a parameter processing unit configured to determine the spatial metadata from the multi-channel input signal. In addition, the system comprises a configuration unit configured to determine one or more control settings for the parameter processing unit based on one or more external settings; wherein the one or more external settings comprise a target data-rate for the bitstream and wherein the one or more control settings comprise a maximum data-rate for the spatial metadata.

The present document describes a method for allocating bits to a frame of a sequence of frames to yield a bitstream having a constant average bitrate, wherein the frame comprises audio data and metadata. The method comprises maintaining an overall bit reservoir and maintaining a virtual bit reservoir being a subset of the overall bit reservoir, such that bits for the metadata of the frame are allocated from the virtual bit reservoir and such that bits for the audio data of the frame are allocated from the overall bit reservoir.

Method and system for bit reservoir control in case of varying metadata

The present document describes a method () for allocating bits to a frame () of a sequence of frames () to yield a bitstream having a constant average bitrate, wherein the frame () comprises audio data and metadata. The method () comprises maintaining () an overall bit reservoir () and maintaining () a virtual bit reservoir () being a subset of the overall bit reservoir (), such that bits for the metadata of the frame () are allocated from the virtual bit reservoir () and such that bits for the audio data of the frame () are allocated from the overall bit reservoir ().

The present document relates to audio coding systems. In particular, the present document relates to efficient methods and systems for parametric multi-channel audio coding. An audio encoding system () configured to generate a bitstream () indicative of a downmix signal and spatial metadata for generating a multi-channel upmix signal from the downmix signal is described. The system () comprises a downmix processing unit () configured to generate the downmix signal from a multi-channel input signal (); wherein the downmix signal comprises m channels and wherein the multi-channel input signal () comprises n channels; n, m being integers with m&#x3c;n. Furthermore, the system () comprises a parameter processing unit () configured to determine the spatial metadata from the multi-channel input signal (). In addition, the system () comprises a configuration unit () configured to determine one or more control settings for the parameter processing unit () based on one or more external settings; wherein the one or more external settings comprise a target data-rate for the bitstream () and wherein the one or more control settings comprise a maximum data-rate for the spatial metadata.

A decoding system reconstructs an audio signal based on an input signal representing the audio signal by parametric coding or by n discretely coded channels. Parametric decoding proceeds on the basis of a core signal and mixing parameters controlling a spatial synthesis stage, which is supplied with a downmix signal. A controller is responsible for controlling the components of the decoding system, whether in steady-state parametric mode, steady-state discrete decoding mode and transitions between these. In defective frames of the input signal, which do not allow the mixing parameters to be decoded, the controller is configured to perform various error handling procedures including: parametric decoding using previous values of the mixing parameters; continuing parametric decoding for a limited duration, and/or outputting the core signal without spatial synthesis.

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Nuremberg, Germany

Tobias R Wagenblass