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 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 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 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: Methods, apparatuses, decoders, and computer programs for replacing decoded parameters in a received multichannel signal are provided. Multichannel parameters of a frame of the signal are decoded. Responsive to a bad frame being indicated, it is determined that a parameter memory is corrupted. Responsive to a bad frame not being indicated: responsive to the parameter memory not being corrupted, a location measure is derived of a reconstructed sound source based on decoded multichannel parameters. Responsive to the parameter memory being corrupted, it is determined, based on the location measure, whether the reconstructed sound source is stable and predominantly concentrated in a subset of channels of multichannels of the received multichannel signal. Responsive to the reconstructed sound source being concentrated in the subset of channels of the multichannels and being stable, parameter recovery is activated to replace decoded multichannel parameters with stored multichannel parameters.

Abstract: A method, apparatus and decoder for replacing decoded parameters in a received multichannel signal in which a frame of consecutive frames of the received multichannel signal is decoded and responsive to receiving a previous frame bad frame indicator while operating in a predictive decoding mode with a current frame of the consecutive frames, it is determined whether a parameter stability measure is below a threshold. Responsive to the parameter stability measure being below the threshold a parameter recovery is activated by retrieving the estimated parameters and replacing decoded parameters of the current frame with the estimated parameters. Otherwise, it is detected whether a source is an active source and responsive to the source being an active source, decoded parameters of the current frame are stored as estimated parameters and the parameter stability measure is determined.

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.