Quantization noise shaping method and apparatus
AssigneeSamsung Electronics Co., Ltd.
InventorsTae-gyu Chang, Heung-yeop Jang
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Abstract
A method and apparatus for shaping quantization noise generated when compressing audio data at a low bit rate is disclosed. A predetermined quantization noise threshold allowed during quantization of sampled audio data and quantization noise energy information of a quantized MDCT coefficient are received in all frequency bands of an audio frequency. The quantization noise energy of the quantized MDCT coefficient is attenuated in a predetermined number of frequency bands in which a difference between the predetermined quantization noise threshold and the quantization noise energy of the quantized MDCT coefficient is large.
Claims17
A method of shaping quantization noise, comprising:
- receiving a predetermined quantization noise threshold allowed during quantization of sampled audio data and quantization noise energy information of quantized MDCT coefficients of a plurality of frequency bands of an audio frequency range;
- and
- attenuating quantization noise energy of quantized MDCT coefficients of a predetermined number of the plurality of frequency bands, wherein differences between the predetermined quantization noise threshold and the quantization noise energy of the quantized MDCT coefficients are relatively large.
A method of shaping quantization noise, comprising:
- during compression of an audio signal at a predetermined bit rate, determining whether quantization noise of a plurality of frequency bands falls below a threshold noise level calculated in a psychoacoustic model;
- and
- if the quantization noise of the plurality of frequency bands does not fall below the threshold noise level, shaping the quantization noise of the plurality of the frequency bands to be substantially equal to the threshold noise level, at or within an offset error.
A method of shaping quantization noise, comprising:
- calculating a total quantization noise of quantized MDCT coefficients and a sum of quantization noise thresholds calculated in a psychoacoustic model;
- comparing the total quantization noise of the quantized MDCT coefficients with the sum of the quantization noise thresholds;
- and
- if the total quantization noise of the quantized MDCT coefficients is less than the sum of the quantization noise thresholds, attenuating quantization noise of a plurality of frequency bands, while if the total quantization noise of the quantized MDCT coefficients is greater than the sum of the quantization noise thresholds, attenuating the quantization noise in selected frequency bands of the plurality of frequency bands.
An apparatus for adjusting a quantization noise distribution, comprising:
- a quantization noise calculator that calculates a total quantization noise of a quantized MDCT coefficient and a sum of quantization noise thresholds calculated in a psychoacoustic model;
- a noise attenuation algorithm selector that compares the total quantization noise of the quantized MDCT coefficient with the sum of the quantization noise thresholds to determine whether a quantization noise attenuation is performed in a plurality of frequency bands or in selected frequency bands of the plurality of frequency bands;
- a quantization noise attenuator that attenuates quantization noise of the plurality of frequency bands;
- and
- a band selective quantization noise attenuator that attenuates quantization noise in the selected frequency bands.
A computer-readable recording medium for recording a computer program code for enabling a computer to provide a service of executing a quantization noise distribution adjustment method, the service comprising the steps of receiving a predetermined quantization noise threshold allowed during a quantization of sampled audio data and quantization noise energy information of quantized MDCT coefficients of a plurality of frequency bands of an audio frequency range and attenuating quantization noise energy of quantized MDCT coefficients of a predetermined number of the plurality of frequency bands, wherein differences between the predetermined quantization noise threshold and the quantization noise energy of the quantized MDCT coefficients are relatively large.
Dependencies are inferred from the claim text.