Patent attributes
The invention concerns audio coding methods and particularly relates to an efficient means by which selected frequency bands of information from an original audio signal which are audible but which are perceptually less relevant need not be encoded, but may be replaced by a noise filling parameter. Those signal bands having content which is perceptually more relevant are, in contrast fully encoded. Encoding bits may be saved in this manner, without leaving voids in the frequency spectrum of the received signal. In this way, this method avoids the annoying bandwidth switching artefacts that can occur when full bandwidth audio is encoded with a bit budget which is too low to represent the signal within each frequency band. Thus, this method allows an increase in the encoded audio bandwidth without introducing annoying bandwidth switching artefacts. The noise filling parameter is a measure of the RMS signal value within the band in question and is used at the reception end by a decoding algorithm to indicate an amount of noise to inject in the frequency band in question.
