US 8,015,001 B2Granted

Signal encoding apparatus and method thereof, and signal decoding apparatus and method thereof

AssigneeSony Corporation

InventorShiro Suzuki

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Abstract

In a signal encoding apparatus (1) a frequency normalization unit (11) normalizes each spectrum of spectral signals by using respectively normalization factors and supplies a normalization factor index per spectrum to a quantization accuracy determining unit (13). The quantization accuracy determining unit (13) adds a weighting factor using auditory properties to the normalization factor index per spectrum of range conversion spectral signals which are subjected to normalization as well as range conversion, and the quantization accuracy is determined according to the result of addition. Then, a quantization unit (14) performs quantization with the quantization accuracy corresponding to a quantization accuracy index supplied from the quantization accuracy determining unit (13), while the encoding/code string generating unit (15) encodes the weighting factor supplied from the quantization accuracy determining unit (13), together with the normalization factor index and the quantized spectral signal.

Claims15

Dependent claims

A signal encoding apparatus comprising:

a spectral transformation unit that transforms an input time domain audio signal per preset unit time to a frequency domain spectral signal;
a normalization unit that receives the frequency domain spectral signal from the spectral transformation unit and (a) generates a plurality of normalized spectral signals by selecting a like plurality of normalization factors having a preset step width with respect to each of a plurality of spectral signal bands and normalizing the spectral signal through use of a selected normalization factor, and (b) generates a normalization factor index by converting the normalization factor per normalized spectrum;
a range conversion unit that receives the normalized spectral signals from the normalization unit and converts the amplitude range of the normalized spectral signals to generate range-converted spectral signals;
a quantization accuracy determining unit that receives the range-converted spectral signals from the range conversion unit and adds a weighting factor per range-converted spectral signal to a normalization factor index used for the normalization and determining quantization accuracy of each normalized spectral signal based on the result of addition;
a quantization unit that quantizes each normalized spectral signal according to the quantization accuracy determined by the quantization accuracy determining means to generate a quantized spectral signal;
and
an encoder that generates code strings by encoding each quantized spectral signal, the normalization factor index, and weight information on the weighting factor,
wherein,
the spectral transformation unit is in direct communication with the encoding to supply information regarding the number of spectral signals generated to the encoding means,
the normalization unit is in direct communication with the encoding means and the quantization accuracy determining means to supply information regarding the normalization factor index to the encoding means and the quantization accuracy, and
the quantization accuracy determining unit is in direct communication with the encoding means to supply said weight information on the weighting factor to the encoding means.

8 more elements

A signal decoding apparatus comprising:

a decoder that decodes an input code string containing a range-converted spectral signals, a quantized spectral signal, a normalization factor index and weight information relating to a weighting factor used in generating the code string;
a quantization accuracy restoring unit in communication with the decoder, the quantization accuracy restoring unit receiving from the decoder the range-converted spectral signals, information on the number of decoded spectra, the normalization information and the weight information as well as maximum quantization information, the quantization accuracy unit adding the weighting factor determined from the weight information per decoded spectra to the normalization factor index to restore the quantization accuracy of range-converted spectral signals based on the result of the addition;
an inverse quantization unit in communication with the decoder and the quantization accuracy restoring unit, the inverse quantization unit receiving from the decoder the information on the number of decoded spectra and the quantization spectrum, the inverse quantization unit receiving from the quantization accuracy restoration unite the range-converted spectral signals, the inverse quantization unit restoring the range-converted spectral signals by inversely quantizing the quantized spectral signal according to the quantization accuracy of each of the range-converted spectral signals;
an inverse range conversion unit in communication with the inverse quantization unit and the decoder, the inverse range conversion unit receiving the inversed quantized spectral signals from the inverse quantization unit and the normalization factor index from the decoder, the inverse range conversion unit converting the range-converted spectral signals into normalized spectral signals;
an inverse normalization unit in communication with the decoder and the inverse range conversion unit, the inverse normalization unit receiving from the decoder the information on the number of decoded spectra and the normalization information, the inverse normalization unit receiving from the inverse range conversion unit the normalized spectral signals, the inverse normalization unit restoring spectral signals by inversely normalizing each of the normalized spectral signals using the normalization factor;
and
an inverse spectral conversion unit in communication with the inverse normalization unit, the inverse spectral conversion unit receiving the normalized spectral signals from the inverse normalization unit and restoring an audio signal per preset unit time by converting the spectral signals.

4 more elements

A signal decoding method comprising:

a decoding step in which a decoder decodes an input code string containing a quantized spectral signal, a normalization factor index and weight information relating to a weighting factor used in generating the code string;
a quantization accuracy restoring step in which information on the number of decoded spectra, the normalization information and the weight information as well as maximum quantization information are communicated to a quantization accuracy restoring unit from the decoder, and the quantization accuracy unit adds the weighting factor determined from the weight information per decoded spectra to the normalization factor index to restore the quantization accuracy of range-converted spectral signals based on the result of the addition;
an inverse quantization step in which the information on the number of decoded spectra and the quantized signal are communicated to a inverse quantization unit from the decoder and the quantization accuracy restoring unit, respectively, and the inverse quantization unit restores the range-converted spectral signals by inversely quantizing the quantized spectral signal according to the quantization accuracy of each of the range-converted spectral signals;
an inverse range conversion step in which the normalizing factor index and the restored range-converted spectral signals are communicated to an inverse quantization unit from the decoder and the inversion quantization unit, respectively, and the range-converted spectral signals are converted into normalized spectral signals by the inverse range conversion unit;
an inverse normalization step in which an inverse normalization unit receives from the decoder the information on the number of decoded spectra and the normalization information, receives the normalized spectral signals from inverse range-conversion unit, and restores a spectral signals by inversely normalizing each of the normalized spectral signals using the normalization factor;
and
an inverse spectral conversion step in which an inverse spectral conversion unit receives the spectral signals from the inverse normalization unit and restores an audio signal per preset unit time by converting the spectral signals.

4 more elements

Dependencies are inferred from the claim text.