Apparatus and method of encoding audio signal by switching frequency domain transformation scheme and time domain transformation scheme

An audio signal decoding apparatus, comprising:

• a first inverse transformation unit to perform any one inverse transformation of a time domain inverse transformation and a frequency domain inverse transformation with respect to a first transformation signal of a first time interval on which a time domain transformation or a frequency domain transformation is performed;
• a second inverse transformation unit to perform the other inverse transformation with respect to a second transformation signal of a second time interval subsequent to the first time interval, the second time interval being adjacent to the first time interval, to generate a second inverse transformation signal, the other inverse transformation being different from the inverse transformation performed by the first inverse transformation;
• a third inverse transformation unit to perform any one of the time domain inverse transformation and the frequency domain inverse transformation, with respect to either the first transformation signal or the second transformation signal based on respective inverse transformation schemes of the first inverse transformation unit and the second inverse transformation unit, to generate a third inverse transformation signal;
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• a signal restoration unit to reconstruct an audio signal of the first time interval based on the first inverse transformation signal and the third inverse transformation signal, or to reconstruct an audio signal of the second time interval based on the second inverse transformation signal and the third inverse transformation signal.

An audio signal coding method, comprising:

• performing any one transformation of a time domain transformation and a frequency domain transformation with respect to a first audio signal of a first time interval to generate a first transformation signal;
• performing the other transformation with respect to a second audio signal of a second time interval subsequent to the first time interval, the second time interval being adjacent to the first time interval, to generate a second transformation signal, the other transformation being different from the transformation performed with respect to the first audio signal;
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• performing any one transformation of the time domain transformation and the frequency domain transformation, with respect to either the first audio signal or the second audio signal based on respective transformation schemes of the performing of the any one transformation and the performing of the other transformation, to generate a third transformation signal,
• wherein the first audio signal is reconstructed based on the first transformation signal and the third transformation signal, and the second audio signal is reconstructed based on the second transformation signal and the third transformation signal.

An audio signal decoding method, comprising:

• performing any one inverse transformation of a time domain inverse transformation and a frequency domain inverse transformation, with respect to a first transformation signal of a first time interval on which either a time domain transformation or a frequency domain transformation is performed, to generate a first inverse transformation signal;
• performing the other inverse transformation with respect to a second transformation signal of a second time interval subsequent to the first time interval, the second time interval being adjacent to the first time interval, to generate a second inverse transformation signal, the other inverse transformation being different from the inverse transformation performed with respect to the first transformation signal;
• performing any one inverse transformation of the time domain inverse transformation and the frequency domain inverse transformation, with respect to either the first transformation signal or the second transformation signal based on respective inverse transformation schemes of the performing of the any one inverse transformation and the performing of the other inverse transformation, to generate a third inverse transformation signal;
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• reconstructing an audio signal of the first time interval based on the first inverse transformation signal and the third inverse transformation signal, or reconstructing an audio signal of the first time interval or the second time interval based on the second inverse transformation signal and the third inverse transformation signal.