Geon-Hyoung Lee

Method and apparatus for encoding envelopes of harmonic signals and method and apparatus for decoding envelopes of harmonic signals

Provided are a methods and apparatuses for encoding/decoding an audio signal to efficiently encode/decode a harmonic envelope. The method of encoding an audio signal includes performing harmonic analysis with respect to an input signal to determine harmonic parameters with respect to harmonic signals; correlating the amplitudes of the harmonic signals to signals in a time domain instead of signals in a frequency domain; applying a time-frequency transformation operation to the amplitudes in the time domain to generate time-frequency transformed values in the frequency domain; and encoding the time-frequency transformed values. When expressing a harmonic envelope, the amplitudes of the harmonic signals are regarded as signals in the time domain so as to perform a time-frequency transformation and only a part from among the transformed values is selected to be encoded. Therefore, sound quality is not affected and coding efficiency greatly improves.