465 results about "Auditory sense" patented technology

An efficient audio coding device that quantizes and encodes digital audio signals with a reduced amount of computation. A spatial transform unit subjects samples of a given audio signal to a spatial transform, thus obtaining transform coefficients of the signal. With a representative value selected out of the transform coefficients of each subband, a quantization step size calculator estimates quantization noise and calculates, in an approximative way, a quantization step size of each subband from the estimated quantization noise, as well as from a masking power threshold determined from a psycho-acoustic model of the human auditory system. A quantizer then quantizes the transform coefficients, based on the calculated quantization step sizes, thereby producing quantized values of those coefficients. The quantization step sizes are also used by a scalefactor calculator to calculate common and individual scalefactors. A coder encodes at least one of the quantized values, common scalefactor, and individual scalefactors.

Any disagreement of the power level before encoding an audio signal and the power level after encoding the audio signal is adjusted to improve the sound quality to the auditory sense. The present invention provides an audio signal encoding apparatus comprising, a band dividing section that divides an input audio signal by a plurality frequency sub-bands, a spectral transform section that transforms the audio signal of each frequency sub-band into a spectral signal, a normalizing section that normalizes each spectral signal by means of a scale factor and generates a normalized spectral signal, a quantizing section that quantizes each normalized spectral signal and generates a quantized spectral signal, a scale factor adjusting section that adjusts the value of the scale factor used by the normalizing section according to the normalized spectral signal and the quantized spectral signal, and an encoding section that encodes at least each quantized spectral signal and the scale factor used by the normalizing section or the scale factor adjusted by the scale factor adjusting section. The scale factor adjusting section 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 section so as to make the absolute value of the difference of the energies not greater than a second threshold value.