Abstract: A method of approximating a lost or corrupted multichannel audio frame of a multichannel audio signal in a decoding device is provided. The device may generate a down-mix error concealment frame and transform the frame into a frequency domain to generate a transformed down-mix error concealment frame. The device may decorrelate the transformed frame to generate a decorrelated concealment frame. The device may obtain a residual signal spectrum of a stored residual signal of a previously received multichannel audio signal frame and generate an energy adjusted decorrelated residual signal concealment frame using the residual signal spectrum. The device may obtain a set of multi-channel audio substitution parameters and provide the frames and substitution parameters to an audio synthesis component to generate a synthesized multichannel audio frame. The device performs an inverse frequency domain transformation of the audio frame to generate a substitution frame for the lost or corrupted audio frame.

Abstract: A method for generation of comfort noise for at least two audio channels. The method comprises determining a spatial coherence between audio signals on the respective audio channels, wherein at least one spatial coherence value per frame and frequency band is determined to form a vector of spatial coherence values. A vector of predicted spatial coherence values is formed by a weighted combination of a first coherence prediction and a second coherence prediction that are combined using a weight factor ?. The method comprises signaling information about the weight factor ? to the receiving node, for enabling the generation of the comfort noise for the at least two audio channels at the receiving node.

Abstract: A method, system, and computer program to encode and decode a channel coherence parameter applied on a frequency band basis, where the coherence parameters of each frequency band form a coherence vector. The coherence vector is encoded and decoded using a predictive scheme followed by a variable bit rate entropy coding.

Abstract: A method and a decoder device of generating a concealment audio subframe of an audio signal are provided. The method comprises generating frequency spectra on a subframe basis where consecutive subframes of the audio signal have a property that an applied window shape of first subframe of the consecutive subframes is a mirrored version or a time reversed version of a second subframe of the consecutive subframes. Peaks of a signal spectrum of a previously received audio signal are detected for a concealment subframe, and a phase of each of the peaks is estimated. A time reversed phase adjustment is derived based on the estimated phase and applied to the peaks of the signal spectrum to form time reversed phase adjusted peaks.

Abstract: A method and a transmitting node for supporting generation of comfort noise for at least two audio channels at a receiving node. The method is performed by a transmitting node. The method comprises determining spectral characteristics of audio signals on at least two input audio channels and determining a spatial coherence between the audio signals. The spatial coherence is associated with perceptual importance measures. A compressed representation of the spatial coherence is determined per frequency band by weighting the spatial coherence within each frequency band according to the perceptual importance measures. Information about the spectral characteristics and the compressed representation of the spatial coherence per frequency band is signaled to the receiving node for enabling the generation of the comfort noise at the receiving node.

Abstract: A method for increasing stability of an inter-channel time difference (ICTD) parameter in parametric audio coding, wherein a multi-channel audio input signal comprising at least two channels is received. The method comprises obtaining an ICTD estimate, ICTDest(m), for an audio frame m and a stability estimate of said ICTD estimate, and determining whether the obtained ICTD estimate, ICTDest(m), is valid. If the ICTDest(m) is not found valid, and a determined sufficient number of valid ICTD estimates have been found in preceding frames, a hang-over time is determined using the stability estimate and a previously obtained valid ICTD parameter, ICTD(m?1), is selected as an output parameter, ICTD(m), during the hang-over time. The output parameter, ICTD(m), is set to zero if valid ICTDest(m) is not found during the hang-over time.

Abstract: A method for generation of comfort noise for at least two audio channels. The method comprises determining a spatial coherence between audio signals on the respective audio channels, wherein at least one spatial coherence value per frame and frequency band is determined to form a vector of spatial coherence values. A vector of predicted spatial coherence values is formed by a weighted combination of a first coherence prediction and a second coherence prediction that are combined using a weight factor ?. The method comprises signaling information about the weight factor ? to the receiving node, for enabling the generation of the comfort noise for the at least two audio channels at the receiving node.

Abstract: A method and a decoder for generating concealment audio frame of an audio signal. The method includes performing a frequency domain analysis of a sequence of previously decoded audio signal to obtain a frequency spectrum and identifying peaks in the spectrum. The method further includes estimating a relative energy between the noise spectrum and the complete spectrum, determining an attenuation of the noise spectrum based on the relative energy, and applying the attenuation to the noise spectrum. The method includes applying an inverse transform to time domain on an error concealment spectrum, that includes the peaks and the attenuated noise spectrum.

Abstract: A method and a transmitting node for supporting generation of comfort noise for at least two audio channels at a receiving node. The method is performed by a transmitting node. The method comprises determining spectral characteristics of audio signals on at least two input audio channels and determining a spatial coherence between the audio signals. The spatial coherence is associated with perceptual importance measures. A compressed representation of the spatial coherence is determined per frequency band by weighting the spatial coherence within each frequency band according to the perceptual importance measures. Information about the spectral characteristics and the compressed representation of the spatial coherence per frequency band is signaled to the receiving node for enabling the generation of the comfort noise at the receiving node.

Abstract: A method of operating an encoder or a decoder. The method comprises receiving an analysis signal of an audio signal and a filtered analysis signal, combining the filtered signal with the analysis signal to generate a combined signal using a maximum function that provides at least one of a maximum positive value at each index i of the combined signal and a maximum negative value at each index i of the combined signal. The method comprises identifying broad peaks and narrow peaks of the combined signal.

Abstract: A method and a decoder for audio decoding, where an encoded primary signal is decoded to form a decoded primary signal, followed by a post-filtering of the decoded primary signal to form a post-filtered signal, where an output signal of the decoder is one of the decoded primary signal and the post-filtered signal. An energy estimation of at least a part of a frequency spectrum of the primary signal being reconstructed by the decoder and an analysis of discontinuities in time domain that is caused by the post-filtering of the decoded primary signal are obtained. A decision variable is generated based on the energy estimation and the analysis of discontinuities obtained. The decision variable is compared to a threshold and the output signal is set to be the decoded primary signal or the post-filtered signal based on the comparing of the decision variable to the threshold.

Abstract: A method for generation of comfort noise for at least two audio channels. The method comprises determining a spatial coherence between audio signals on the respective audio channels, wherein at least one spatial coherence value per frame and frequency band is determined to form a vector of spatial coherence values. A vector of predicted spatial coherence values is formed by a weighted combination of a first coherence prediction and a second coherence prediction that are combined using a weight factor ?. The method comprises signaling information about the weight factor ? to the receiving node, for enabling the generation of the comfort noise for the at least two audio channels at the receiving node.

Abstract: A method, system, and computer program to encode and decode a channel coherence parameter applied on a frequency band basis, where the coherence parameters of each frequency band form a coherence vector. The coherence vector is encoded and decoded using a predictive scheme followed by a variable bit rate entropy coding.

Abstract: A method for increasing stability of an inter-channel time difference (ICTD) parameter in parametric audio coding, wherein a multi-channel audio input signal comprising at least two channels is received. The method comprises obtaining an ICTD estimate, ICTDest(m), for an audio frame m and a stability estimate of said ICTD estimate, and determining whether the obtained ICTD estimate, ICTDest(m), is valid. If the ICTDest(m) is not found valid, and a determined sufficient number of valid ICTD estimates have been found in preceding frames, a hang-over time is determined using the stability estimate and a previously obtained valid ICTD parameter, ICTD(m?1), is selected as an output parameter, ICTD(m), during the hang-over time. The output parameter, ICTD(m), is set to zero if valid ICTDest(m) is not found during the hang-over time.

Abstract: A method for generation of comfort noise for at least two audio channels. The method comprises determining a spatial coherence between audio signals on the respective audio channels, wherein at least one spatial coherence value per frame and frequency band is determined to form a vector of spatial coherence values. A vector of predicted spatial coherence values is formed by a weighted combination of a first coherence prediction and a second coherence prediction that are combined using a weight factor a. The method comprises signaling information about the weight factor a to the receiving node, for enabling the generation of the comfort noise for the at least two audio channels at the receiving node.

Abstract: A method and a transmitting node for supporting generation of comfort noise for at least two audio channels at a receiving node. The method is performed by a transmitting node. The method comprises determining spectral characteristics of audio signals on at least two input audio channels and determining a spatial coherence between the audio signals. The spatial coherence is associated with perceptual importance measures. A compressed representation of the spatial coherence is determined per frequency band by weighting the spatial coherence within each frequency band according to the perceptual importance measures. Information about the spectral characteristics and the compressed representation of the spatial coherence per frequency band is signaled to the receiving node for enabling the generation of the comfort noise at the receiving node.

Abstract: A method and apparatus for voice or sound activity detection for spatial audio. The method comprises receiving direct source information source detection decision and a primary voice/sound activity decision, and producing a spatial voice/sound activity decision based on the direct source detection decision and the primary voice/sound activity decision.

Abstract: A method, system, and computer program to encode and decode a channel coherence parameter applied on a frequency band basis, where the coherence parameters of each frequency band form a coherence vector. The coherence vector is encoded and decoded using a predictive scheme followed by a variable bit rate entropy coding.

Abstract: A method and a decoder device of generating a concealment audio subframe of an audio signal are provided. The method comprises generating frequency spectra on a subframe basis where consecutive subframes of the audio signal have a property that an applied window shape of first subframe of the consecutive subframes is a mirrored version or a time reversed version of a second subframe of the consecutive subframes. Peaks of a signal spectrum of a previously received audio signal are detected for a concealment subframe, and a phase of each of the peaks is estimated. A time reversed phase adjustment is derived based on the estimated phase and applied to the peaks of the signal spectrum to form time reversed phase adjusted peaks.

Abstract: A method and a transmitting node for supporting generation of comfort noise for at least two audio channels at a receiving node. The method is performed by a transmitting node. The method comprises determining spectral characteristics of audio signals on at least two input audio channels and determining a spatial coherence between the audio signals. The spatial coherence is associated with perceptual importance measures. A compressed representation of the spatial coherence is determined per frequency band by weighting the spatial coherence within each frequency band according to the perceptual importance measures. Information about the spectral characteristics and the compressed representation of the spatial coherence per frequency band is signaled to the receiving node for enabling the generation of the comfort noise at the receiving node.