Method and an apparatus for processing an audio signal

A non-transitory computer-readable medium having instructions stored thereon, which causes the processor to perform operations, comprising:

• comparing a size information of at least two blocks of A+1 level with a size information of a block of A level corresponding to the at least two of A+1 level;
• and,
• determining the at least two blocks of A+1 level as an optimum block if the size information of the at least two blocks of A+1 level is less than the size information of the block of A level, and determining the block of A level as the optimum block if the size information of the block of A level is less than the size information of the at least two blocks of A+1 level.

An apparatus for processing an audio signal, comprising:

• a initial comparing part comparing a size information of at least two blocks of A+1 level with a size information of a block of A level corresponding to the at least two of A+1 level;
• and,
• a conditional comparing part determining the at least two blocks of A+1 level as an optimum block if the size information of the at least two blocks of A+1 level is less than the size information of the block of A level, and determining the block of A level as the optimum block if the size information of the block of A level is less than the size information of the at least two blocks of A+1 level.