Support for generation of comfort noise

An audio encoder for enabling generation of comfort noise for at least two audio channels at an audio decoder, the audio encoder being configured to:

• receive at least two input audio signals on the respective input audio channels;
• determine spectral characteristics of the input audio signals;
• determine perceptual importance measures based on the spectral characteristics;
• determine a spatial coherence between the input audio signals;
• divide the spatial coherence into frequency bands, wherein a compressed representation of the spatial coherence is determined per frequency band by determining a weighted mean of the spatial coherence by weighting the spatial coherence within each frequency band according to the perceptual importance measures, wherein spatial coherence values within each frequency band are weighted such that the spatial coherence values corresponding to values of frequency coefficients with a higher energy has more impact on said spatial coherence value compared to the spatial coherence values corresponding to values of frequency coefficients with lower energy;
• and
• signal information about the spectral characteristics and information about the compressed representation of the spatial coherence per frequency band to the audio decoder, for enabling the generation of the comfort noise for the at least two audio channels at the audio decoder, wherein an energy spectrum |LR(m,k)|2 of lr(m,n)=w1l(m,n)+w2r(m,n), where l(m,n) denotes the input signal for the left channel, r(m,n) denotes the input signal for the right channel, and w1 and w2 denote weights, defines the perceptual importance measures within frame m and is used for weighting the spatial coherence values.

A non-transitory computer readable medium comprising instructions for supporting generation of comfort noise for at least two audio signals at an audio decoder, the non-transitory computer readable medium comprising computer code which, when run on processing circuitry of an audio encoder, causes the audio encoder to:

• receive at least two input audio signals on the respective input audio channels;
• determine spectral characteristics of the input audio signals;
• determine perceptual importance measures based on the spectral characteristics;
• determine a spatial coherence between the input audio signals;
• divide the spatial coherence into frequency bands, wherein a compressed representation of the spatial coherence is determined per frequency band by determining a weighted mean of the spatial coherence by weighting the spatial coherence within each frequency band according to the perceptual importance measures, wherein spatial coherence values within each frequency band are weighted such that the spatial coherence values corresponding to values of frequency coefficients with a higher energy has more impact on said spatial coherence value compared to the spatial coherence values corresponding to values of frequency coefficients with lower energy;
• and
• signal information about the spectral characteristics and information about the compressed representation of the spatial coherence per frequency band to the audio decoder, for enabling the generation of the comfort noise for the at least two audio channels at the audio decoder,
• wherein an energy spectrum |LR (m,k)|2 of lr(m,n)=w1l(m,n)+w2r(m,n), where l(m,n) denotes the input signal for the left channel, r(m,n) denotes the input signal for the right channel, and w1 and w2 denote weights, defines the perceptual importance measures within frame m and is used for weighting the spatial coherence values.