A decoder for generating a frequency enhanced audio signal, includes: a feature extractor for extracting a feature from a core signal; a side information extractor for extracting a selection side information associated with the core signal; a parameter generator for generating a parametric representation for estimating a spectral range of the frequency enhanced audio signal not defined by the core signal, wherein the parameter generator is configured to provide a number of parametric representation alternatives in response to the feature, and wherein the parameter generator is configured to select one of the parametric representation alternatives as the parametric representation in response to the selection side information; and a signal estimator for estimating the frequency enhanced audio signal using the parametric representation selected.

A decoder for generating a frequency enhanced audio signal, includes: a feature extractor for extracting a feature from a core signal; a side information extractor for extracting a selection side information associated with the core signal; a parameter generator for generating a parametric representation for estimating a spectral range of the frequency enhanced audio signal not defined by the core signal, wherein the parameter generator is configured to provide a number of parametric representation alternatives in response to the feature, and wherein the parameter generator is configured to select one of the parametric representation alternatives as the parametric representation in response to the selection side information; and a signal estimator for estimating the frequency enhanced audio signal using the parametric representation selected.

The present document relates to audio encoding and decoding. In particular, the present document relates to audio coding schemes which make use of high frequency reconstruction (HFR) methods. A system configured to determine a master scale factor band table of a highband signal (105) of an audio signal is described. The highband signal (105) is to be generated from a lowband signal (101) of the audio signal using a high frequency reconstruction (HFR) scheme. The master scale factor band table is indicative of a frequency resolution of a spectral envelope of the highband signal (105).

The present document relates to audio encoding and decoding. In particular, the present document relates to audio coding schemes which make use of high frequency reconstruction (HFR) methods. A system configured to determine a master scale factor band table of a highband signal (105) of an audio signal is described. The highband signal (105) is to be generated from a lowband signal (101) of the audio signal using a high frequency reconstruction (HFR) scheme. The master scale factor band table is indicative of a frequency resolution of a spectral envelope of the highband signal (105).

A multi-channel audio signal coding method includes obtaining a to-be-encoded first audio frame, pairing at least five channel signals according to a first pairing manner to obtain a first channel pair set, obtaining a first sum of correlation values of the first channel pair set, where one channel pair has one correlation value, pairing the at least five channel signals according to a second pairing manner to obtain a second channel pair set, obtaining a second sum of correlation values of the second channel pair set, determining a target pairing manner of the at least five channel signals based on the first sum of correlation values and the second sum of correlation values, and encoding the at least five channel signals based on a channel pair set corresponding to the target pairing manner, where the target pairing manner is the first pairing manner or the second pairing manner.

A multi-channel audio signal coding method includes obtaining a to-be-encoded first audio frame, pairing at least five channel signals according to a first pairing manner to obtain a first channel pair set, obtaining a first sum of correlation values of the first channel pair set, where one channel pair has one correlation value, pairing the at least five channel signals according to a second pairing manner to obtain a second channel pair set, obtaining a second sum of correlation values of the second channel pair set, determining a target pairing manner of the at least five channel signals based on the first sum of correlation values and the second sum of correlation values, and encoding the at least five channel signals based on a channel pair set corresponding to the target pairing manner, where the target pairing manner is the first pairing manner or the second pairing manner.

A communication device includes a loudspeaker to transmit sound into a room. A signal having a white noise-like frequency spectrum spanning a frequency range of human hearing is generated. Auditory thresholds of human hearing for frequencies spanning the frequency range are stored. Respective levels of background noise in the room at the frequencies are determined. The white noise-like frequency spectrum is spectrally shaped to produce a shaped frequency spectrum having, for each frequency, a respective level that follows either the auditory threshold or the level of background noise at that frequency, whichever is greater. The shaped frequency spectrum is transmitted from the loudspeaker into the room.

An apparatus comprising means for: receiving values for sub-bands of a frame of an audio signal, the values comprising at least one azimuth value, at least one elevation value and at least one energy ratio value for each sub-band; determining an allocation of first number of bits to encode the values of the frame, wherein the first number of bits are fixed; encoding the at least one energy ratio value for a frame based on a defined allocation of a second number of bits from the first number of bits; encoding the at least one azimuth value and/or at least one elevation value of the frame based on a defined allocation of a third number of bits from the first number of bits, wherein the third number of bits is variably distributed on a sub-band-by-sub-band basis.

An apparatus comprising means for: receiving values for sub-bands of a frame of an audio signal, the values comprising at least one azimuth value, at least one elevation value and at least one energy ratio value for each sub-band; determining an allocation of first number of bits to encode the values of the frame, wherein the first number of bits are fixed; encoding the at least one energy ratio value for a frame based on a defined allocation of a second number of bits from the first number of bits; encoding the at least one azimuth value and/or at least one elevation value of the frame based on a defined allocation of a third number of bits from the first number of bits, wherein the third number of bits is variably distributed on a sub-band-by-sub-band basis.

An apparatus for decoding an encoded audio signal to obtain a reconstructed audio signal includes a receiving interface for receiving one or more frames comprising information on a plurality of audio signal samples of an audio signal spectrum of the encoded audio signal, and a processor for generating the reconstructed audio signal. The processor is configured to generate the reconstructed audio signal by fading a modified spectrum to a target spectrum, if a current frame is not received by the receiving interface or if the current frame is received by the receiving interface but is corrupted, wherein the modified spectrum includes a plurality of modified signal samples, wherein, for each of the modified signal samples of the modified spectrum, an absolute value of the modified signal sample is equal to an absolute value of one of the audio signal samples of the audio signal spectrum.