A computer-readable storage medium storing computer instructions, that when executed by one or more processors, cause the one or more processors to perform the steps of: splitting (S202) spectral coefficients of a current data frame of an audio signal into subbands of the current data frame; acquiring (S101, S203) quantized frequency envelope values of the subbands of the current data frame; acquiring signal types of a first quantity of subbands in the current data frame; acquiring stored reference information of a second quantity of subbands in a previous data frame of the current data frame, wherein the second quantity is less than or equal to the first quantity; determining modification factors of the first quantity of subbands according to acquired signal types of the first quantity of subbands and acquired reference information of the second quantity of subbands: modifying (S102, S205) quantized frequency envelope values of the first quantity of subbands by using the modification factors of the first quantity of subbands; allocating (S103, S206) quantization bits to the subbands of the current data frame according to modified quantized frequency envelope values of the first quantity of subbands; quantizing (S104, S207) a spectral coefficient of a subband to which a quantization bit is allocated in the subbands of the current data frame; and writing (S105, S208) the quantized spectral coefficient of the subband to which a quantization bit is allocated into a bitstream. splitting (S202) spectral coefficients of a current data frame of an audio signal into subbands of the current data frame; acquiring (S101, S203) quantized frequency envelope values of the subbands of the current data frame; acquiring signal types of a first quantity of subbands in the current data frame; acquiring stored reference information of a second quantity of subbands in a previous data frame of the current data frame, wherein the second quantity is less than or equal to the first quantity; determining modification factors of the first quantity of subbands according to acquired signal types of the first quantity of subbands and acquired reference information of the second quantity of subbands: modifying (S102, S205) quantized frequency envelope values of the first quantity of subbands by using the modification factors of the first quantity of subbands; allocating (S103, S206) quantization bits to the subbands of the current data frame according to modified quantized frequency envelope values of the first quantity of subbands; quantizing (S104, S207) a spectral coefficient of a subband to which a quantization bit is allocated in the subbands of the current data frame; and writing (S105, S208) the quantized spectral coefficient of the subband to which a quantization bit is allocated into a bitstream. modifying (S102, S205) quantized frequency envelope values of the first quantity of subbands by using the modification factors of the first quantity of subbands; allocating (S103, S206) quantization bits to the subbands of the current data frame according to modified quantized frequency envelope values of the first quantity of subbands; quantizing (S104, S207) a spectral coefficient of a subband to which a quantization bit is allocated in the subbands of the current data frame; and writing (S105, S208) the quantized spectral coefficient of the subband to which a quantization bit is allocated into a bitstream. <EOS>