Patent ID: 7627469
Filing Date: 2009-12-01
Classification: G10L

Abstract:
1. An audio signal encoding apparatus comprising: a band dividing unit for dividing an input audio signal by a plurality frequency sub-bands; a spectral transform unit for transforming the audio signal of each frequency sub-band into a spectral signal; a normalizing unit for normalizing each spectral signal by means of a scale factor and generating a normalized spectral signal; a quantizing unit for quantizing each normalized spectral signal and generating a quantized spectral signal; a scale factor adjusting unit for adjusting the value of the scale factor used by the normalizing unit according to the normalized spectral signal and the quantized spectral signal; and an encoding unit for encoding at least each quantized spectral signal and the scale factor used by the normalizing unit or the scale factor adjusted by the scale factor adjusting unit, wherein, the scale factor adjusting unit is adapted to compare the absolute value of the difference of the energy of the normalized spectral signal and the energy of the quantized spectral signal with a first threshold value for each frequency sub-band and, if the absolute value of the difference is greater than the first threshold value, adjust the value of the scale factor used by the normalizing unit so as to make the absolute value of the difference of the energies not greater than a second threshold value.