Signal processing apparatus and method, and program

A signal processing method of a signal processing apparatus that performs signal processing on a code string obtained by dividing an input digital signal into blocks along the time axis, performing gain control on each block along the time axis, normalizing with a positive value a signal component on which the gain control has been performed, quantizing the normalized signal component, and coding and multiplexing along with gain control function generation information on generating a gain control function for performing the gain control and normalization coefficient information, the signal processing method comprising the steps of:

• adjusting a level of the signal by adding or subtracting an integer value to or from the normalization coefficient information in the code string;
• calculating, by the apparatus, a cutoff amount for a case where the normalization coefficient information after subtraction is cut off at a minimum possible value thereof because a subtracted amount of the normalization coefficient is larger than the normalization coefficient information;
• and
• modifying, by the apparatus, gain control function generation information according to the calculated cutoff amount.

A non-transitory, computer-readable storage medium storing a program that, when executed by a computer, causes the computer to perform a process on a code string obtained by dividing an input digital signal into blocks along the time axis, performing gain control on each block along the time axis, normalizing with a positive value a signal component on which the gain control has been performed, quantizing the normalized signal component, coding and multiplexing along with gain control function generation information on generating a gain control function for performing the gain control and normalization coefficient information, the process comprising the steps of:

• adjusting a level of the signal by adding or subtracting an integer value to or from the normalization coefficient information in the code string;
• calculating a cutoff amount for a case where the normalization coefficient information after subtraction is cut off at a minimum possible value thereof because a subtracted amount of the normalization coefficient is larger than the normalization coefficient information;
• and
• modifying gain control function generation information according to the calculated cutoff amount.