Audio encoder, audio decoder, methods for encoding and decoding an audio signal, and a computer program

摘要

An encoder for providing an audio stream on the basis of a transform-domain representation of an input audio signal includes a quantization error calculator configured to determine a multi-band quantization error over a plurality of frequency bands of the input audio signal for which separate band gain information is available. The encoder also includes an audio stream provider for providing the audio stream such that the audio stream includes information describing an audio content of the frequency bands and information describing the multi-band quantization error.;A decoder for providing a decoded representation of an audio signal on the basis of an encoded audio stream representing spectral components of frequency bands of the audio signal includes a noise filler for introducing noise into spectral components of a plurality of frequency bands to which separate frequency band gain information is associated on the basis of a common multi-band noise intensity value.

主权项

1. A decoder for providing a decoded representation of an audio signal on the basis of an encoded audio stream representing spectral components of frequency bands of the audio signal, the decoder comprising:
a noise filler configured to introduce noise into spectral components of a plurality of frequency bands, to which separate frequency band gain information is associated, on the basis of a common multi-band noise intensity value;wherein the noise filler is configured to receive a plurality of spectral bin values representing different overlapping or non-overlapping frequency portions of the first frequency band of a frequency domain audio signal representation, and to receive a plurality of spectral bin values representing different overlapping or non-overlapping frequency portions of the second frequency band of the frequency domain audio signal representation; and
to replace one or more spectral bin values of the first frequency band of the plurality of frequency bands with a first spectral bin noise value, a magnitude of which is determined by the multi-band noise intensity value, and to replace one or more spectral bin values of the second frequency band of the plurality of frequency bands with a second spectral bin noise value comprising the same magnitude as the first spectral bin noise value; wherein the decoder further comprises a scaler configured to scale spectral bin values of the first frequency band of the plurality of frequency bands with a first frequency band gain value, to acquire scaled spectral bin values of the first frequency band, and to scale spectral bin values of the second frequency band of the plurality of frequency bands with a second frequency band gain value, to acquire scaled spectral bin values of the second frequency band, such that the replaced spectral bin values, replaced with the first and second spectral bin noise values, are scaled with different frequency band gain values, andsuch that the replaced spectral bin value, replaced with the first spectral bin noise value, and un-replaced spectral bin values of the first frequency band representing an audio content of the first frequency band are scaled with the first frequency band gain value, and that the replaced spectral bin value, replaced with the second spectral bin noise value, and un-replaced spectral bin values of the second frequency band representing an audio content of the second frequency band are scaled with the second frequency band gain value.