Method for Encoding and Decoding Multi-Channel Audio Signal and Apparatus Thereof

A decoding apparatus comprising:

• a demultiplexer which extracts an encoded down-mix signal and additional information from an input signal;
• a core decoder which generates a down-mix signal by decoding the encoded down-mix signal;
• a parameter decoder which extracts spatial information and a compensation parameter relating an envelope of the down-mix signal to an envelope of a multi-channel audio signal that is used to generate the down-mix signal, from the additional information, the compensation parameter corresponding to the envelope of each channel of the multi-channel audio signal;
• the parameter decoder which extracts compensation information indicating whether the compensation parameter is applied to the multi-channel audio signal;
• and
• a multi-channel synthesization unit which generates a multi-channel audio signal based on the down-mix signal and the spatial information and compensates the envelope of each channel of the multi-channel audio signal based on the compensation parameter when the compensation parameter is applied to the multi-channel audio signal.

An encoding method comprising:

• calculating spatial information based on a multi-channel audio signal and a down-mix signal;
• generating compensation information indicating whether a compensation parameter is applied to the multi-channel audio signal;
• and
• calculating a compensation parameter relating an envelope of the down-mix signal to an envelope of the multi-channel audio signal that is used to generate the down-mix signal based on the multi-channel audio signal and the down-mix signal, the compensation parameter being calculated for each channel of the multi-channel audio signal when the compensation parameter is applied to the multi-channel audio signal.

An encoding apparatus comprising:

• a down-mix unit which generating a down-mix signal from a multi-channel audio signal;
• a spatial information calculation unit which calculates spatial information based on the multi-channel audio signal and the down-mix signal;
• a compensation parameter calculation unit which generates compensation information indicating whether a compensation parameter is applied to the multi-channel audio signal, and calculates the compensation parameter relating an envelope of the down-mix signal to an envelope of the multi-channel audio signal that is used to generate the down-mix signal based on the multi-channel audio signal and the down-mix signal, the compensation parameter being calculated for each channel of the multi-channel audio signal when the compensation parameter is applied to the multi-channel audio signal;
• and
• a bitstream generation unit which generates a bitstream by encoding the spatial information, the compensation parameter, and the down-mix signal and combining results of the encoding.