Abstract: 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.

Abstract: 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.

Abstract: An audio bitstream is decoded into audio objects and audio metadata for the audio objects. The audio objects include a specific audio object. The audio metadata specifies frame-level gains that include a first gain and a second gain respectively for a first audio frame and a second audio frame. It is determined, based on the first and second gains, whether sub-frame gains are to be generated for the specific audio object. If so, a ramp length is determined for a ramp used to generate the sub-frame gains for the specific audio object. The ramp of the ramp length is used to generate the sub-frame gains for the specific audio object. A sound field represented by the audio objects with the sub-frame gains is rendered by audio speakers.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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 (500) configured to generate a bitstream (564) indicative of a downmix signal and spatial metadata for generating a multi-channel upmix signal from the downmix signal is described. The system (500) comprises a downmix processing unit (510) configured to generate the downmix signal from a multi-channel input signal (561); wherein the downmix signal comprises m channels and wherein the multi-channel input signal (561) comprises n channels; n, m being integers with m<n. Furthermore, the system (500) comprises a parameter processing unit (520) configured to determine the spatial metadata from the multi-channel input signal (561).

Abstract: 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.

Abstract: 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 (500) configured to generate a bitstream (564) indicative of a downmix signal and spatial metadata for generating a multi-channel upmix signal from the downmix signal is described. The system (500) comprises a downmix processing unit (510) configured to generate the downmix signal from a multi-channel input signal (561); wherein the downmix signal comprises m channels and wherein the multi-channel input signal (561) comprises n channels; n, m being integers with m<n. Furthermore, the system (500) comprises a parameter processing unit (520) configured to determine the spatial metadata from the multi-channel input signal (561).

Abstract: 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.

Abstract: A multi-channel synthesizer includes a post processor for determining post processed reconstruction parameters or quantities derived from the reconstruction parameter for an actual time portion of the input signal so that the post processed reconstruction parameter or the post processed quantity is different from the corresponding quantized and inversely quantized reconstruction parameter in that the value of the post processed reconstruction parameter or the derived quantity is not bound by the quantization step size. A multi-channel reconstructor uses the post-processed reconstruction parameter for reconstructing the multi-channel output signal.

Abstract: A multi-channel synthesizer includes a post processor for determining post processed reconstruction parameters or quantities derived from the reconstruction parameter for an actual time portion of the input signal so that the post processed reconstruction parameter or the post processed quantity is different from the corresponding quantized and inversely quantized reconstruction parameter in that the value of the post processed reconstruction parameter or the derived quantity is not bound by the quantization step size. A multi-channel reconstructor uses the post-processed reconstruction parameter for reconstructing the multi-channel output signal.