Method and Device for Decoding Signal

A computer program product comprising computer-executable instructions stored on a non-transitory computer-readable medium that, when executed by a processor, cause an audio decoder to:

• obtain a first spectral coefficient of a first sub-band of a current frame of an audio signal by decoding a bitstream, wherein the first sub-band includes a plurality of spectral coefficients;
• obtain a first average quantity of allocated bits per spectral coefficient of the first sub-band;
• obtain a first noise filling gain for the first sub-band when the first average quantity is less than a threshold;
• generate, according to the first noise filling gain, a second spectral coefficient;
• obtain a frequency domain audio signal according to the first spectral coefficient and the second spectral coefficient;
• and
• generate a time domain audio signal according to the frequency domain signal.