METHOD AND APPARATUS FOR ENCODING AND DECODING AUDIO SIGNAL USING BAND WIDTH EXTENSION TECHNIQUE AND STEREO ENCODING TECHNIQUE

摘要

A method and an apparatus for encoding and decoding an audio signal by using bandwidth extension technique and stereo encoding technique are provided to output encoded stereo parameters, bitplane and bandwidth extension information as an encoded result in response to an input signal, thereby encoding high frequency components and stereo components efficiently at a limited bit rate to improve sound quality. A method for encoding an audio signal comprises the following steps of: extracting stereo parameters from an input signal and performing the down-mixing of the input signal(1300); dividing the down-mixed signal into a low frequency band signal and a high frequency band signal(1310); converting the high frequency band signal and the low frequency band signal from a time domain to a frequency domain separately(1320); quantizing the converted low frequency band signal to encode the low frequency band signal into bitplane(1330); generating and encoding bandwidth extension information indicating a characteristic of the converted high frequency band signal by using the converted low frequency band signal(1340); and outputting the encoded stereo parameters, bitplane and bandwidth extension information as an encoded result in response to the input signal(1350).