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, the instructions causing the processor to be configured to:
• obtain a high-band signal of a current frame of the audio signal and a low-band signal of the current frame of the audio signal;
• encode the low-band signal of the current frame to obtain a low-band excitation signal;
• perform linear prediction on the high-band signal of the current frame 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 excitation signal and the quantized linear prediction coefficient;
• divide the predicted high-band signal into M subframes, wherein the M is an integer greater than two;
• perform windowing on a first subframe of the M subframes and a last subframe of the M subframes using a first asymmetric window function;
• and
• perform the windowing on a subframe except the first subframe and the last subframe of the M subframes.

A computer program product comprising a non-transitory computer readable storage medium storing program code thereon for processing an audio signal, the program code comprising instructions for executing a method that comprises:

• obtaining a high-band signal of a current frame of the audio signal and a low-band signal of the current frame of the audio signal;
• encoding the low-band signal of the current frame to obtain a low-band excitation signal;
• performing linear prediction on the high-band signal of the current frame to obtain a linear prediction coefficient;
• quantizing the linear prediction coefficient to obtain a quantized linear prediction coefficient;
• obtaining a predicted high-band signal according to the low-band excitation signal and the quantized linear prediction coefficient;
• dividing the predicted high-band signal into M subframes, wherein the M is an integer greater than two;
• performing windowing on a first subframe of the M subframes and a last subframe of the M subframes using a first asymmetric window function;
• and
• performing the windowing on a subframe except the first subframe and the last subframe of the M subframes.