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Frequency-domain comfort noise generation for discontinuous transmission in EVS

: Lombard, Anthony; Wilde, Stephan; Ravelli, Emmanuel; Dohla, Stefan; Fuchs, Guillaume; Dietz, Martin


Institute of Electrical and Electronics Engineers -IEEE-; IEEE Signal Processing Society:
IEEE 40th IEEE International Conference on Acoustics, Speech and Signal Processing, ICASSP 2015. Proceedings. Vol.8 : 19-24 April 2015, Brisbane, Australia
Piscataway, NJ: IEEE, 2015
ISBN: 978-1-4673-6997-8
ISBN: 978-1-4673-6998-5
International Conference on Acoustics, Speech, and Signal Processing (ICASSP) <40, 2015, Brisbane>
Fraunhofer IIS ()
Standards in der Audiocodierung

Discontinuous Transmission (DTX) is an efficient way to drastically reduce the transmission rate of a communication codec in the absence of voice input. In this mode, most frames that are determined to consist of background noise only are dropped from transmission and replaced by some Comfort Noise Generation (CNG) in the decoder. In this paper, we propose a novel CNG approach combining information gained about the actual background noise at both encoder and decoder side. It is able to better reproduce background noise types showing a pronounced spectral tilt, which is difficult for traditional schemes based on a linear prediction model. The proposed technique operates in the frequency domain. It is part of the Enhanced Voice Services (EVS) codec, where it is known as FDCNG. Listening tests show the superior quality of FD-CNG over existing approaches for certain background noise such as car noise.