Bandwidth extension method and apparatus, electronic device, and computer-readable storage medium

A bandwidth extension (BWE) apparatus, comprising a processor and a memory, the memory storing computer-readable instructions executable by the processor, the processor being configured to:

• determine parameters of a low-frequency spectrum of a narrowband signal, the parameters of the low-frequency spectrum comprising a low-frequency amplitude spectrum;
• input the parameters of the low-frequency spectrum into a neural network model, and obtain a correlation parameter based on an output of the neural network model, the correlation parameter representing a correlation between a high-frequency part and a low-frequency part of a target broadband spectrum and comprising a high-frequency spectrum envelope;
• obtain a low-frequency spectrum envelope of the narrowband signal according to the low-frequency amplitude spectrum;
• generate an initial high-frequency amplitude spectrum based on the low-frequency amplitude spectrum;
• adjust the initial high-frequency amplitude spectrum based on the high-frequency spectrum envelope and the low-frequency spectrum envelope, to obtain a target high-frequency amplitude spectrum;
• generate a corresponding high-frequency phase spectrum based on a low-frequency phase spectrum of the narrowband signal;
• obtain a high-frequency spectrum according to the target high-frequency amplitude spectrum and the high-frequency phase spectrum;
• and
• obtain a broadband signal after BWE based on the low-frequency spectrum and the high-frequency spectrum.

A non-transitory computer-readable storage medium, storing computer-readable instructions, the computer-readable instructions, when loaded and executed by a processor, causing the processor to perform:

• determining parameters of a low-frequency spectrum of a narrowband signal, the parameters of the low-frequency spectrum comprising a low-frequency amplitude spectrum;
• inputting the parameters of the low-frequency spectrum into a neural network model, and obtaining a correlation parameter based on an output of the neural network model, the correlation parameter representing a correlation between a high-frequency part and a low-frequency part of a target broadband spectrum and comprising a high-frequency spectrum envelope;
• obtaining a low-frequency spectrum envelope of the narrowband signal according to the low-frequency amplitude spectrum;
• generating an initial high-frequency amplitude spectrum based on the low-frequency amplitude spectrum;
• adjusting the initial high-frequency amplitude spectrum based on the high-frequency spectrum envelope and the low-frequency spectrum envelope, to obtain a target high-frequency amplitude spectrum;
• generating a corresponding high-frequency phase spectrum based on a low-frequency phase spectrum of the narrowband signal;
• obtaining a high-frequency spectrum according to the target high-frequency amplitude spectrum and the high-frequency phase spectrum;
• and
• obtaining a broadband signal after BWE based on the low-frequency spectrum and the high-frequency spectrum.