<p>An audio data processing unit (120) performs a decode process and a compression/encoding process on audio data in a frame unit formed by a predetermined number of samples. The obtained encoded data is temporarily accumulated in an encode data buffer (110). A music composition change detection unit (106) identifies a frame boundary as a music composition change point according to music composition position information corresponding to the audio data and feature information expressing a feature of the audio data outputted from a feature extraction signal processing unit (107).A frame boundary division unit (111) corrects the encoded data which is accumulated in the encode data buffer (110) so that the frame boundary of the encoded data is matched with the identified frame boundary.</p>
