In a method to decode signals, a computing device decodes spectral coefficients of a current frame are grouped into a plurality of sub-bands. The computing device classifies a sub-band as a bit allocation unsaturated sub-band based on an average quantity of allocated bits per spectral coefficient of a sub-band of the plurality of sub-bands and a threshold. The computing device obtains a noise filling gain based on an envelope of the sub-band, and obtains a reconstructed spectral coefficient of the sub-band by performing noise filling based on the noise filling gain. The computing device then obtains a frequency domain audio signal based on spectral coefficients in the sub-band obtained by decoding and the reconstructed spectral coefficient.

In a method to decode signals, a computing device decodes spectral coefficients of a current frame are grouped into a plurality of sub-bands. The computing device classifies a sub-band as a bit allocation unsaturated sub-band based on an average quantity of allocated bits per spectral coefficient of a sub-band of the plurality of sub-bands and a threshold. The computing device obtains a noise filling gain based on an envelope of the sub-band, and obtains a reconstructed spectral coefficient of the sub-band by performing noise filling based on the noise filling gain. The computing device then obtains a frequency domain audio signal based on spectral coefficients in the sub-band obtained by decoding and the reconstructed spectral coefficient.

A high-band encoding/decoding method and device for bandwidth extension are provided. A high-band encoding method comprising the steps of: generating sub band-specific bit allocation information on the basis of a low-band envelope; determining, on the basis of the sub band-specific bit allocation information, the sub band requiring an envelope update in a high band; and generating, for the determined sub band, refinement data relating to the envelope update. A high-band decoding method comprising the steps of: generating sub band-specific bit allocation information on the basis of a low-band envelope; determining, on the basis of the sub band-specific bit allocation information, the sub band requiring an envelope update in a high band; and decoding, for the determined sub band, refinement data relating to the envelope update, thereby updating the envelope.

A high-band encoding/decoding method and device for bandwidth extension are provided. A high-band encoding method comprising the steps of: generating sub band-specific bit allocation information on the basis of a low-band envelope; determining, on the basis of the sub band-specific bit allocation information, the sub band requiring an envelope update in a high band; and generating, for the determined sub band, refinement data relating to the envelope update. A high-band decoding method comprising the steps of: generating sub band-specific bit allocation information on the basis of a low-band envelope; determining, on the basis of the sub band-specific bit allocation information, the sub band requiring an envelope update in a high band; and decoding, for the determined sub band, refinement data relating to the envelope update, thereby updating the envelope.

A device for processing audio signals includes an interchannel temporal mismatch analyzer, an interchannel phase difference (IPD) mode selector and an IPD estimator. The interchannel temporal mismatch analyzer is configured to determine an interchannel temporal mismatch value indicative of a temporal misalignment between a first audio signal and a second audio signal. The IPD mode selector is configured to select an IPD mode based on at least the interchannel temporal mismatch value. The IPD estimator is configured to determine IPD values based on the first audio signal and the second audio signal. The IPD values have a resolution corresponding to the selected IPD mode.

An apparatus comprising means configured to: obtain at least one direction parameter value for a time-frequency part of at least one audio signal (301); obtain at least one energy ratio for the time-frequency part (301), wherein each energy ratio is associated with a respective direction parameter value; generate respective at least one modified energy ratio from the at least one energy ratio for the time-frequency part (304); determine a quantization spatial resolution for encoding the at least one obtained direction parameter value based on the at least one modified energy ratio (305); and encode the obtained direction parameter values based on the quantization spatial resolution (306).

An encoding system encodes multiple audio signals (X) as a downmix signal (Y) together with wet and dry upmix coefficients (P, C). In a decoding system, a pre-multiplier (101) computes an intermediate signal (W) by mapping the downmix signal linearly in accordance with a first set of coefficients (Q); a decorrelating section (102) outputs a decorrelated signal (Z) based on the intermediate signal; a wet upmix section (103) computes a wet upmix signal by mapping the decorrelated signal linearly in accordance with the wet upmix coefficients; a dry upmix section (104) computes a dry upmix signal by mapping the downmix signal linearly in accordance with the dry upmix coefficients; a combining section (105) provides a multidimensional reconstructed signal (X) by combining the wet and dry upmix signals; and a converter (106) computes the first set of coefficients based on the wet and dry upmix coefficients and supplies this to the pre-multiplier.

An encoding system encodes multiple audio signals (X) as a downmix signal (Y) together with wet and dry upmix coefficients (P, C). In a decoding system, a pre-multiplier (101) computes an intermediate signal (W) by mapping the downmix signal linearly in accordance with a first set of coefficients (Q); a decorrelating section (102) outputs a decorrelated signal (Z) based on the intermediate signal; a wet upmix section (103) computes a wet upmix signal by mapping the decorrelated signal linearly in accordance with the wet upmix coefficients; a dry upmix section (104) computes a dry upmix signal by mapping the downmix signal linearly in accordance with the dry upmix coefficients; a combining section (105) provides a multidimensional reconstructed signal (X) by combining the wet and dry upmix signals; and a converter (106) computes the first set of coefficients based on the wet and dry upmix coefficients and supplies this to the pre-multiplier.

Systems and techniques for compression and decoding of audio data are generally disclosed. An example device for compressing higher order ambisonic (HOA) coefficients representative of a soundfield includes a memory configured to store audio data and one or more processors configured to: determine when to use ambient HOA coefficients of the HOA coefficients to augment one or more foreground audio objects obtained through decomposition of the HOA coefficients based on one or more singular values also obtained through the decomposition of the HOA coefficients, the ambient HOA coefficients representative of an ambient component of the soundfield.

Systems and techniques for compression and decoding of audio data are generally disclosed. An example device for compressing higher order ambisonic (HOA) coefficients representative of a soundfield includes a memory configured to store audio data and one or more processors configured to: determine when to use ambient HOA coefficients of the HOA coefficients to augment one or more foreground audio objects obtained through decomposition of the HOA coefficients based on one or more singular values also obtained through the decomposition of the HOA coefficients, the ambient HOA coefficients representative of an ambient component of the soundfield.