Encoding device, decoding device and system for the distribution of audio data

摘要

An audio data input unit (310) of an encoding device 300 splits an audio data string into contiguous 4,096 samples of audio data, and a transforming unit (320) transforms the split audio data into spectral data in a frequency domain. A data dividing unit (330) divides the spectral data into that in a lower frequency band and that in a higher frequency band at 11.025 kHz (f1) as a boundary. The spectral data in the lower frequency band is quantized and encoded by a first quantizing unit (340) and an encoding unit (350) as usual. A second quantizing unit (345) generates sub information indicating a characteristic of the spectral data in the higher frequency band, and a second encoding unit (355) encodes the sub information. A stream output unit (390) integrates the codes obtained by the first and second encoding units (350), (355), and outputs the integrated one. Here, the f1 is a half or less of a sampling frequency f2 at which the audio data string is created.