Method and apparatus for processing temporal envelope of audio signal, and encoder

An apparatus for processing an audio signal, comprising:

• a memory comprising instructions;
• and
• a processor in communication with the memory, wherein the processor executes the instructions to:
• obtain a high-band signal of a current frame signal;
• divide the high-band signal of the current frame signal into M subframes, wherein M is an integer that is greater than or equal to 2;
• perform windowing on a first subframe of the M subframes and a last subframe of the M subframes by using a first asymmetric window function, and
• perform windowing on a subframe except the first subframe and the last subframe of the M subframes.

An encoder, wherein the encoder is configured to:

• obtain a low-band signal of a current frame signal and a high-band signal of the current frame signal according to the current frame signal received by the encoder;
• encode the low-band signal of the current frame signal to obtain a low-band encoded excitation signal;
• perform linear prediction on the high-band signal of the current frame signal to obtain a linear prediction coefficient;
• quantize the linear prediction coefficient to obtain a quantized linear prediction coefficient;
• obtain a predicted high-band signal according to the low-band encoded excitation signal and the quantized linear prediction coefficient;
• dividing the predicted high-band signal into M subframes, wherein M is an integer that is greater than or equal to 2;
• performing windowing on a first subframe of the M subframes and a last subframe of the M subframes by using an asymmetric window function;
• and
• performing windowing on a subframe except the first subframe and the last subframe of the M subframes.