Audio coding and decoding apparatuses and methods, and recording mediums storing the methods
First Claim
1. An audio coding apparatus comprising:
- a first harmonic coding module performing first harmonic coding on an input audio signal using a pitch lag of the input audio signal and producing a quantized linear prediction coding coefficient;
a first detector detecting a first difference audio signal from a difference between an audio signal output from the first harmonic coding module and the input audio signal;
a second harmonic coding module performing harmonic coding on the first difference audio signal using the quantized linear prediction coding coefficient and a previous harmonic coding result;
a second detector detecting a second difference audio signal obtained from a difference between an audio signal output from the second harmonic coding module and the first difference audio signal; and
a code excited linear prediction (CELP) module CELP coding the second difference audio signal using the quantized linear prediction coding coefficient obtained from the first harmonic coding module.
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Abstract
Audio coding and decoding apparatuses and methods that can optimize the quality of an audio signal including harmonics, and recording mediums storing the methods. An audio coding apparatus includes: a first harmonic coding module performing first harmonic coding on an input audio signal using a pitch lag of the input audio signal and producing a quantized linear prediction coding coefficient; a first detector detecting a first difference audio signal from a difference between an audio signal output from the first harmonic coding module and the input audio signal; a second harmonic coding module performing harmonic coding on the first difference audio signal using the quantized linear prediction coding coefficient and a previous harmonic coding result; a second detector detecting a second difference audio signal obtained from a difference between an audio signal output from the second harmonic coding module and the first difference audio signal; and a code excited linear prediction (CELP) module CELP coding the second difference audio signal using the quantized linear prediction coding coefficient obtained from the first harmonic coding module.
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Citations
25 Claims
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1. An audio coding apparatus comprising:
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a first harmonic coding module performing first harmonic coding on an input audio signal using a pitch lag of the input audio signal and producing a quantized linear prediction coding coefficient;
a first detector detecting a first difference audio signal from a difference between an audio signal output from the first harmonic coding module and the input audio signal;
a second harmonic coding module performing harmonic coding on the first difference audio signal using the quantized linear prediction coding coefficient and a previous harmonic coding result;
a second detector detecting a second difference audio signal obtained from a difference between an audio signal output from the second harmonic coding module and the first difference audio signal; and
a code excited linear prediction (CELP) module CELP coding the second difference audio signal using the quantized linear prediction coding coefficient obtained from the first harmonic coding module. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. An audio decoding apparatus comprising:
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an inverse quantization unit inverse quantizing each of a plurality of parameters to restore an audio signal;
a first harmonic decoding module performing harmonic decoding using a linear prediction coding coefficient and a phase vector output from the inverse quantization unit;
a second harmonic decoding module performing harmonic decoding based on the linear prediction coding coefficient, a harmonic index, and a first gain value output from the inverse quantization unit;
a first adder adding a signal output from the first harmonic decoding module to a signal output from the second harmonic decoding module;
a code excited linear prediction (CELP) decoding module performing CELP decoding based on a stochastic codebook index output from the inverse quantization unit and a second gain value output from the inverse quantization unit; and
a second adder adding a signal output from the first adder to a signal output from the CELP decoding module and outputting the result as a restored audio signal. - View Dependent Claims (15, 16, 17, 18)
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19. An audio coding method comprising:
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harmonically coding an input audio signal without analyzing a linear prediction coding coefficient;
analyzing a linear prediction coding coefficient of a difference audio signal obtained from a difference between the input audio signal and the harmonic-coding result and harmonically coding the difference audio signal; and
CELP coding a difference audio signal obtained from a difference between the result of harmonically coding on the difference audio signal and the input audio signal. - View Dependent Claims (20, 21, 22)
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23. An audio decoding method comprising:
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inverse quantizing a plurality of parameters for restoring an audio signal;
first harmonic decoding using a linear prediction coding coefficient and a phase vector obtained through the inverse quantizing;
second harmonic decoding using a linear prediction coding coefficient, a harmonic index, and a first gain value obtained through the inverse quantizing;
first adding the first harmonic decoding result to the second harmonic decoding result;
CELP decoding using a stochastic index and a second gain value obtained through the inverse quantization; and
adding the result obtained through the first adding to the result obtained through the CELP decoding to obtain a restored audio signal.
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24. A recording medium on which a program for performing an audio coding method is recorded, the audio coding method comprising:
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harmonically coding an input audio signal without analyzing a linear prediction coding coefficient;
analyzing a linear prediction coding coefficient of a difference audio signal obtained from a difference between the input audio signal and the harmonic-coding result and harmonically coding the difference audio signal; and
CELP coding a difference audio signal obtained from a difference between the result of harmonically coding on the difference audio signal and the input audio signal.
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25. A recording medium on which a program for performing an audio decoding method is performed, the audio decoding method comprising:
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inverse quantizing a plurality of parameters for restoring an audio signal;
first harmonic decoding using a linear prediction coding coefficient and a phase vector obtained through the inverse quantizing;
second harmonic decoding using a linear prediction coding coefficient, a harmonic index, and a first gain value obtained through the inverse quantizing;
first adding the first harmonic decoding result to the second harmonic decoding result;
CELP decoding using a stochastic index and a second gain value obtained through the inverse quantization; and
second adding the result obtained through the first adding to the result obtained through the CELP decoding to obtain a restored audio signal.
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Specification