AUDIO ENCODING DEVICE AND AUDIO DECODING DEVICE
First Claim
1. An audio coding apparatus comprising:
- a first coding section that codes an input signal and generates first coded data;
a first local decoding section that decodes the first coded data, and generates a first decoded signal;
a subtractor section that subtracts the first decoded signal from the input signal, and generates an error signal;
a second coding section that codes only a portion of spectral coefficients of the error signal, and generates second coded data;
a spectral envelope shaping parameter calculation section that calculates a spectral envelope shaping parameter; and
a quantization section that quantizes the spectral envelope shaping parameter, and generates third coded data.
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Accused Products
Abstract
Provided is an audio encoding device that can suppress degradation of audio quality. Spectral coefficients of synthesized signal from CELP core layer are utilized to fulfill spectral gaps in error signal spectrum coefficients from a transform coding layer. By both spectral coefficients, decoded signal spectral coefficients are generated. The decoded signal spectral coefficients and the input signal spectral coefficients are divided into a plurality of sub bands. In each sub band, the energy of the input signal spectral coefficient corresponding to a zero decoded error signal spectral coefficient is calculated, and the energy of the decoded signal spectral coefficient corresponding to the zero decoding error signal spectral coefficient is calculated, and their energy ratio is calculated and is quantized and transmitted.
30 Citations
20 Claims
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1. An audio coding apparatus comprising:
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a first coding section that codes an input signal and generates first coded data; a first local decoding section that decodes the first coded data, and generates a first decoded signal; a subtractor section that subtracts the first decoded signal from the input signal, and generates an error signal; a second coding section that codes only a portion of spectral coefficients of the error signal, and generates second coded data; a spectral envelope shaping parameter calculation section that calculates a spectral envelope shaping parameter; and a quantization section that quantizes the spectral envelope shaping parameter, and generates third coded data. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. An audio decoding apparatus comprising:
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a first decoding section that decodes first coded data and generates a first decoded signal; a second decoding section that decodes second coded data, and generates decoded error signal spectral coefficients comprising zero decoded error signal spectral coefficients and non-zero decoded error signal spectral coefficients; a first adder section that adds spectral coefficients of the first decoded signal and the decoded error signal spectral coefficients, and generates decoded signal spectral coefficients; a dequantization section that dequantizes third coded data and generates a decoded spectral envelope shaping parameter; a spectral envelope shaping section that shapes the decoded signal spectral coefficients using the decoded spectral envelope shaping parameter, and generates a shaped decoded signal spectral coefficient; a second adder section that adds the decoded error signal spectral coefficients and the shaped decoded signal spectral coefficients, and generates a post-processing error signal; and a third adder section that adds the first decoded signal and the post-processing error signal, and generates an output signal. - View Dependent Claims (14, 15, 16, 17, 18)
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19. An audio coding method comprising:
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generating first coded data by coding an input signal; generating a first decoded signal by decoding the first coded data; generating an error signal by subtracting the first decoded signal from the input signal; generating second coded data by coding only a portion of spectral coefficients of the error signal; calculating a spectral envelope shaping parameter; and generating third coded data by quantizing the spectral envelope shaping parameter.
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20. An audio decoding method comprising:
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generating a first decoded signal by decoding first coded data; generating, by decoding second coded data, decoded error signal spectral coefficients comprising zero decoded error signal spectral coefficients and non-zero decoded error signal spectral coefficients; generating decoded signal spectral coefficients by adding spectral coefficients of the first decoded signal and the decoded error signal spectral coefficients; generating a decoded spectral envelope shaping parameter by dequantizing third coded data; generating shaped decoded signal spectral coefficients by shaping the decoded signal spectral coefficients using the decoded spectral envelope shaping parameter; generating a post-processing error signal by adding the decoded error signal spectral coefficients and the shaped decoded signal spectral coefficients; and generating an output signal by adding the first decoded signal and the post-processing error signal.
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Specification