METHOD AND APPARATUS TO EXTRACT IMPORTANT FREQUENCY COMPONENT OF AUDIO SIGNAL AND METHOD AND APPARATUS TO ENCODE AND/OR DECODE AUDIO SIGNAL USING THE SAME
First Claim
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1. A method of extracting an important frequency component of an audio signal, the method comprising:
- converting an audio signal of a time domain into an audio signal of a frequency domain;
selecting a frequency band having a harmonic feature from the converted audio signal of the frequency domain; and
extracting an important frequency component from the selected frequency band having the harmonic feature.
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Abstract
A method and apparatus to extract an important frequency component of an audio signal and a method and apparatus to encode and/or decode an audio signal by using the same. The method of extracting an important frequency component of an audio signal includes converting an audio signal of a time domain into an audio signal of a frequency domain, selecting a frequency band having a harmonic feature from the converted audio signal of the frequency domain, and extracting an important frequency component from the selected frequency band having the harmonic feature.
70 Citations
24 Claims
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1. A method of extracting an important frequency component of an audio signal, the method comprising:
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converting an audio signal of a time domain into an audio signal of a frequency domain; selecting a frequency band having a harmonic feature from the converted audio signal of the frequency domain; and extracting an important frequency component from the selected frequency band having the harmonic feature. - View Dependent Claims (2, 3, 4, 5)
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6. A method of extracting an important frequency component of an audio signal, the method comprising:
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converting an audio signal of a time domain into an audio signal of a frequency domain; dividing the audio signal of the frequency domain into subbands according to a predetermined reference, and determining whether each of the subbands has a harmonic feature or not; extracting an important frequency component based on a harmonic model from the audio signal of the subband having the harmonic feature according to the determination result; and extracting an important frequency component based on a psychoacoustic model from the audio signal of the subband not having the harmonic feature according to the determination result.
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7. An apparatus for extracting an important frequency component of an audio signal, the apparatus comprising:
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a signal converting unit converting an audio signal of a time domain into an audio signal of a frequency domain; a harmonic feature determining unit determining which frequency band of the converted audio signal has a harmonic feature; a first extracting unit extracting an important frequency component based on a harmonic model from the audio signal of the frequency band the having the harmonic feature; and a second extracting unit extracting an important frequency component based on a psychoacoustic model from the audio signal of the frequency band not having the harmonic feature. - View Dependent Claims (8, 9, 10, 11, 12, 13)
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14. A method of encoding an audio signal, the method comprising:
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converting an audio signal of a time domain into an audio signal of a frequency domain; selecting a frequency band having a harmonic feature from the converted audio signal of the frequency domain; extracting an important frequency component having the harmonic feature from the selected frequency band having the harmonic feature; extracting a harmonic parameter from the important frequency component; and encoding an audio signal by using the extracted harmonic parameter. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22)
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23. A method of decoding an audio signal, the method comprising:
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decoding information including period information of a harmonic peak, quantizing step magnitude information, and a quantized value of an audio signal; inverse-quantizing the quantized value of the audio signal by using the decoded information; and converting the inverse-quantized value into a signal of a time domain.
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24. A method of decoding an audio signal, the method comprising:
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decoding ISC (important spectrum component) extracting mode information, information including a quantized step magnitude information and a quantized value of an audio signal, period information of a harmonic peak, or index information representing whether an ISC exists or not from an encoded bit stream; inverse-quantizing the quantized value of the audio signal by using the decoded information according to the ISC extracting mode information; and converting the inverse-quantized value into a signal of a time domain.
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Specification