NOISE FILLING IN PERCEPTUAL TRANSFORM AUDIO CODING

摘要

Noise filling in perceptual transform audio codecs is improved by performing the noise filling with a spectrally global tilt, rather than in a spectrally flat manner.

主权项

1. Perceptual transform audio decoder comprising
a noise filler configured to perform noise filling on a spectrum of an audio signal by filling the spectrum with noise so as to acquire a noise filled spectrum; and a frequency domain noise shaper configured to subject the noise filled spectrum to spectral shaping using a spectral perceptual weighting function, wherein the frequency domain noise shaper is configured to determine the spectral perceptual weighting function from linear prediction coefficient information signaled in a data stream into which the spectrum is coded, or determine the spectral perceptual weighting function from scale factors relating to scale factor bands, signaled in the data stream into which the spectrum is coded, wherein the noise filler is configured to generate an intermediary noise signal; identify contiguous spectral zero-portions of the audio signal's spectrum; determine a function for each contiguous spectral zero-portion depending on
the respective contiguous spectral zero-portion's width so that the function is confined to the respective contiguous spectral zero-portion,the respective contiguous spectral zero-portion's spectral position so that a scaling of the function depends on the respective contiguous spectral zero-portion's spectral position such that an amount of the scaling monotonically increases or decreases with increasing frequency of the respective contiguous spectral zero-portion's spectral position; and spectrally shape, for each contiguous spectral zero-portion, the intermediary noise signal using the function determined for the respective contiguous spectral zero-portion such that the noise exhibits a spectrally global tilt comprising a negative slope.