Method and apparatus for encoding audio signal, and method and apparatus for decoding audio signal

Time for each audio band-decoding method and apparatus of the encoding method and apparatus and an audio signal of an audio signal using a mixture of frequency method and parametric methods is disclosed. The encoding method according to the invention, dividing the input audio signal into a plurality of audio band, for selecting a respective coding scheme per audio band contains all of the encoded data for each step, and the audio band to encode in accordance with a selected coding scheme generating a bit stream, comprising the steps of: selecting a respective coding scheme per audio band parametric coding scheme and a time-selected that the size of the data encoded in the frequency (time-frequency) coding scheme smaller. By encoding by dividing the audio signal into a plurality of band select the coding scheme, the size of the encoded data for each band smaller, as compared to applying a coding scheme with respect to the entire audio data, the effect capable of efficient encoding have.