Audio signal encoding and decoding method, and audio signal encoding and decoding apparatus

An audio signal encoding method, comprising:

• dividing a time domain audio signal into a low band signal and a high band signal;
• encoding the low band signal to obtain one or more low frequency encoding parameters;
• calculating a voiced degree factor according to the low frequency encoding parameters;
• predicting a high band excitation signal according to the low frequency encoding parameters;
• obtaining a synthesized excitation signal according to the high band excitation signal and the voiced degree factor;
• and
• obtaining one or more high frequency encoding parameters based on the synthesized excitation signal and the high band signal;
• wherein the low frequency encoding parameters comprise an algebraic codebook, an algebraic codebook gain, an adaptive codebook, an adaptive codebook gain, and a pitch period, and wherein predicting the high band excitation signal according to the low frequency encoding parameters comprises:
• modifying the voiced degree factor using the pitch period to obtain a modified voiced degree factor;
• obtaining a weighted sum of the algebraic codebook and random noise using the modified voiced degree factor as a weighting factor;
• and
• obtaining the high band excitation signal by adding a product of the weighted sum and the algebraic codebook gain and a product of the adaptive codebook and the adaptive codebook gain.

An audio signal encoding apparatus comprising:

• a processor and a memory storing computer-readable instructions for execution by the processor;
• wherein the processor is configured to execute the instructions to:
• divide a time domain signal into a low band signal and a high band signal;
• encode the low band signal to obtain one or more low frequency encoding parameters;
• calculate a voiced degree factor according to the low frequency encoding parameters;
• predict a high band excitation signal according to the low frequency encoding parameters;
• obtain a synthesized excitation signal according to the high band excitation signal and the voiced degree factor;
• and
• obtain one or more high frequency encoding parameters based on the synthesized excitation signal and the high band signal;
• wherein the low frequency encoding parameters comprise an algebraic codebook, an algebraic codebook gain, an adaptive codebook, an adaptive codebook gain, and a pitch period, and in predicting the high band excitation signal according to the low frequency encoding parameters, the processor is configured to execute the instructions to:
• modify the voiced degree factor using the pitch period to obtain a modified voiced degree factor;
• and
• obtain a weighted sum of the algebraic codebook and random noise using the modified voiced degree factor as a weighting factor;
• and
• obtain the high band excitation signal by adding a product of the weighted sum and the algebraic codebook gain and a product of the adaptive codebook and the adaptive codebook gain.