Patent ID: 7974837

Claim:
An audio encoding apparatus for encoding an audio signal, said audio encoding apparatus comprising: a pitch cycle detection unit operable to detect a pitch cycle of an audio signal; a framing unit operable to frame the audio signal based on the detected pitch cycle; a first waveform modification unit operable to perform waveform modification on the framed audio signal, in conformance with a time-frequency transformation frame length, and to output a waveform-modified audio signal; a time-frequency transformation unit operable to transform the waveform-modified audio signal into a frequency parameter, for every predetermined time-frequency transformation frame length; an encoding unit operable to encode the frequency parameter; and a multiplex unit operable to multiplex the encoded frequency parameter from said encoding unit and the pitch cycle, and to output the multiplexed result as a bit stream, wherein said first waveform modification unit includes: a first cutting unit operable to cut the framed audio signal in conformance with the pitch cycle; and a first duplication unit operable to duplicate part of a waveform signal of a pitch cycle of an adjacent encoded frame in between a waveform signal of a pitch cycle of a current encoded frame and the waveform signal of the pitch cycle of the adjacent encoded frame, so as to generate the waveform-modified audio signal of the time-frequency transformation frame length.