Abstract: A multi-channel input signal having at least three original channels is represented by a parameter representation of the multi-channel signal. A first balance parameter, a first coherence parameter, or a first inter-channel time difference between a first channel pair and a second balance parameter, or a second coherence parameter, or a second inter-channel time difference parameter between a second channel pair are calculated. This set of parameters is the parameter representation of the original signals. The first channel pair has two channels, which are different from two channels of a second channel pair. Furthermore, each channel of the two channel pairs is one of the original channels, or a weighted combination of the original channels, and the first channel pair and the second channel pair include information on the three original channels.

Abstract: For a multi-channel reconstruction of audio signals based on at least one base channel, an energy measure is used for compensating energy losses due to an predictive upmix. The energy measure can be applied in the encoder or the decoder. Furthermore, a decorrelated signal is added to output channels generated by an energy-loss introducing upmix procedure. The energy of the decorrelated signal is smaller than or equal to an energy error introduced by the predictive upmix. Thus, problems occurring for prediction based up-mix methods such as up-mixing signals that are coded with High Frequency Reconstruction techniques are solved, so that the correct correlation between the up-mixed channels is obtained or the up-mix is adapted to arbitrary down-mixes.

Abstract: The invention relates to an apparatus for improving a stereo audio signal of an FM stereo radio receiver. The apparatus comprises a parametric stereo (PS) parameter estimation stage. The parameter estimation stage is configured to determine one or more parametric stereo parameters based on the stereo audio signal in a frequency-variant or frequency-invariant manner. Preferably, these PS parameters are time- and frequency-variant. Moreover, the apparatus comprises an upmix stage. The upmix stage is configured to generate the improved stereo signal based on a first audio signal and the one or more parametric stereo parameters. The first audio signal is obtained from the stereo audio signal, e.g. by a downmix operation in a downmix stage. The PS parameter estimation stage may be part of a PS encoder. The upmix stage may be part of a PS decoder.

Abstract: A parameter representation of a multi-channel signal having several original channels includes a parameter set, which, when used together with at least one down-mix channel allows a multi-channel reconstruction. An additional level parameter is calculated such that an energy of the at least one downmix channel weighted by the level parameter is equal to a sum of energies of the original channels. The additional level parameter is transmitted to a multi-channel reconstructor together with the parameter set or together with a down-mix channel. An apparatus for generating a multi-channel representation uses the level parameter to correct the energy of the at least one transmitted down-mix channel before entering the down-mix signal into an up-mixer or within the up-mixing process.

Abstract: For generating a parametric representation of a multi-channel signal especially suitable for low-bit rate applications, only the location of the maximum of the sound energy within a replay setup is encoded and transmitted using direction parameter information. For multi-channel reconstruction, the energy distribution of the output channels identified by the direction parameter information is controlled by the direction parameter information, while the energy distribution in the remaining ambience channels is not controlled by the direction parameter information.

Abstract: A method and a device are described for processing a stereo signal obtained from an encoder, which encodes an N-channel audio signal into spatial parameters (P) and a stereo down-mix comprising first and second stereo signals (LO, RO). A first signal and a third signal are added in order to obtain a first output signal (L0w), wherein the first signal (L0wL) comprises the first stereo signal (LO) modified by a first complex function (g1), and the third signal (L0wR) comprises the second stereo signal (RO) modified by a third complex function (g3). A second signal and a fourth signal are added to obtain a second output signal (R0w). The fourth signal (R0wR) comprises the second stereo signal (RO) modified by a fourth complex function (g4), and the second signal (R0wL) comprises the first stereo signal (LO) modified by a second complex function (g2).

Abstract: Parameters being a measure for a characteristic of a channel or of a pair of channels, wherein the parameter is a measure for a characteristic of the channel or of the pair of channels with respect to another channel of a multi-channel signal can be quantized more efficiently using a quantization rule that is generated based on a relation of an energy measure of the channel or the pair of channels and an energy measure of the multi-channel signal. With generation of the quantization rule taking into account a psycho acoustic approach, the size of an encoded representation of the multi-channel signal can be decreased by coarser quantization without significantly disturbing the perceptual quality of the multi-channel signal when reconstructed from the encoded representation.

Abstract: A parametric representation of a multi-channel audio signal having parameters suited to be used together with a monophonic downmix signal to calculate a reconstruction of the multi-channel audio signal can efficiently be derived in a stereo-backwards compatible way when a parameter combiner is used to generate the parametric representation by combining a one or more spatial parameters and a stereo parameter resulting in a parametric representation having a decoder usable stereo parameter and an information on the one or more spatial parameters that represents, together with the decoder usable stereo parameter, the one or more spatial parameters.

Abstract: A multi-channel input signal having at least three original channels is represented by a parameter representation of the multi-channel signal. A first balance parameter, a first coherence parameter, or a first inter-channel time difference between a first channel pair and a second balance parameter, or a second coherence parameter, or a second inter-channel time difference parameter between a second channel pair are calculated. This set of parameters is the parameter representation of the original signals. The first channel pair has two channels, which are different from two channels of a second channel pair. Furthermore, each channel of the two channel pairs is one of the original channels, or a weighted combination of the original channels, and the first channel pair and the second channel pair include information on the three original channels.

Abstract: A parameter calculator calculates lower resolution parametric information and interpolation information. On a decoder-side, an upmixer is used for generating the output channels. The upmixer uses high resolution parametric information generated by a parameter interpolator using the low resolution parametric information and decoder-side derived interpolation information or encoder-generated interpolation information for selecting one of a plurality of different interpolation characteristics.

Abstract: A parametric representation of a multi-channel audio signal describes the spatial properties of the audio signal well with compact side information when a coherence information, describing the coherence between a first and a second channel, is derived within a hierarchical encoding process only for channel pairs including a first channel having only information of a left side with respect to a listening position and including a second channel having only information from a right side with respect to a listening position. As within the hierarchical process the multiple audio channels of the audio signal are downmixed iteratively into monophonic channels, one can pick the relevant parameters from an encoding step involving only channel pairs carrying the information needed to describe the spatial properties of the multi-channel audio signal.

Abstract: An audio encoder (109) has a hierarchical encoding structure and generates a data stream comprising one or more audio channels as well as parametric audio encoding data. The encoder (109) comprises an encoding structure processor (305) which inserts decoder tree structure data into the data stream. The decoder tree structure data comprises at least one data value indicative of a channel split characteristic for an audio channel at a hierarchical layer of the hierarchical decoder structure and may specifically specify the decoder tree structures to be applied by a decoder. A decoder (115) comprises a receiver (401) which receives the data stream and a decoder structure processor (405) for generating the hierarchical decoder structure in response to the decoder tree structure data. A decode processor (403) then generates output audio channels from the data stream using the hierarchical decoder structure.

Abstract: A parameter representation of a multi-channel signal having several original channels includes a parameter set, which, when used together with at least one down-mix channel allows a multi-channel reconstruction. An additional level parameter is calculated such that an energy of the at least one downmix channel weighted by the level parameter is equal to a sum of energies of the original channels. The additional level parameter is transmitted to a multi-channel reconstructor together with the parameter set or together with a down-mix channel. An apparatus for generating a multi-channel representation uses the level parameter to correct the energy of the at least one transmitted down-mix channel before entering the down-mix signal into an up-mixer or within the up-mixing process.

Abstract: A parametric representation of a multi-channel audio signal having parameters suited to be used together with a monophonic downmix signal to calculate a reconstruction of the multi-channel audio signal can efficiently be derived in a stereo-backwards compatible way when a parameter combiner is used to generate the parametric representation by combining a one or more spatial parameters and a stereo parameter resulting in a parametric representation having a decoder usable stereo parameter and an information on the one or more spatial parameters that represents, together with the decoder usable stereo parameter, the one or more spatial parameters.

Abstract: A method and a device are described for processing a stereo signal obtained from an encoder, which encodes an N-channel audio signal into spatial parameters (P) and a stereo down-mix comprising first and second stereo signals (L0, R0). A first signal and a third signal are added in order to obtain a first output signal (Low), wherein the first signal (L0wL) comprises the first stereo signal (L0) modified by a first complex function (g1), and the third signal (L0wR) comprises the second stereo signal (R0) modified by a third complex function (g3). A second signal and a fourth signal are added to obtain a second output signal (R0w). The fourth signal (R0wR) comprises the second stereo signal (R0) modified by a fourth complex function (g4), and the second signal (R0wL) comprises the first stereo signal (L0) modified by a second complex function (g2).

Abstract: A multi-channel input signal having at least three original channels is represented by a parameter representation of the multi-channel signal. A first balance parameter, a first coherence parameter, or a first inter-channel time difference between a first channel pair and a second balance parameter, or a second coherence parameter, or a second inter-channel time difference parameter between a second channel pair are calculated. This set of parameters is the parameter representation of the original signals. The first channel pair has two channels, which are different from two channels of a second channel pair. Furthermore, each channel of the two channel pairs is one of the original channels, or a weighted combination of the original channels, and the first channel pair and the second channel pair include information on the three original channels.

Abstract: A multi-channel synthesizer for generating at least three output channels using an input signal having at least one base channel, the base channel being derived from the original multi-channel signal, the input signal further including at least two different up-mixing parameters, and an up-mixer mode indication indicating, in a first state that a first up-mixing rule is to be performed, and, indicating, in a second state, that a different second up-mixing rule is to be performed, uses an up-mixer for up-mixing the at least one base channel using the at least two different up-mixing parameters based on the first or the second up-mixing rule in response to the up-mixer mode indication so that the at least three output channels are obtained.

Abstract: A multi-channel input signal having at least three original channels is represented by a parameter representation of the multi-channel signal. A first balance parameter, a first coherence parameter, or a first inter-channel time difference between a first channel pair and a second balance parameter, or a second coherence parameter, or a second inter-channel time difference parameter between a second channel pair are calculated. This set of parameters is the parameter representation of the original signals. The first channel pair has two channels, which are different from two channels of a second channel pair. Furthermore, each channel of the two channel pairs is one of the original channels, or a weighted combination of the original channels, and the first channel pair and the second channel pair include information on the three original channels.

Abstract: For generating a parametric representation of a multi-channel signal especially suitable for low-bit rate applications, only the location of the maximum of the sound energy within a replay setup is encoded and transmitted using direction parameter information. For multi-channel reconstruction, the energy distribution of the output channels identified by the direction parameter information is controlled by the direction parameter information, while the energy distribution in the remaining ambience channels is not controlled by the direction parameter information.

Abstract: A parameter representation of a multi-channel signal having several original channels includes a parameter set, which, when used together with at least one down-mix channel allows a multi-channel reconstruction. An additional level parameter is calculated such that an energy of the at least one downmix channel weighted by the level parameter is equal to a sum of energies of the original channels. The additional level parameter is transmitted to a multi-channel reconstructor together with the parameter set or together with a down-mix channel. An apparatus for generating a multi-channel representation uses the level parameter to correct the energy of the at least one transmitted down-mix channel before entering the down-mix signal into an up-mixer or within the up-mixing process.