Method and apparatus for neural network-based audio encoding using subband decomposition

An audio processing apparatus comprising:

• at least one memory configured to store program code;
• and
• at least one processor configured to read the program code and operate as instructed by the program code, the program code comprising:
• decomposition code configured to cause at least one of the at least one processor to decompose an audio signal into a low-frequency subband signal and a high-frequency subband signal;
• feature extraction code configured to cause at least one of the at least one processor to:
• perform convolution on the low-frequency subband signal to obtain a convolution feature of the low-frequency subband signal;
• perform pooling on the convolution feature to obtain a pooling feature of the low-frequency subband signal;
• and
• obtain a low-frequency feature of the low-frequency subband signal based on the pooling feature of the low-frequency subband signal;
• high-frequency analysis code configured to cause at least one of the at least one processor to obtain a high-frequency feature of the high-frequency subband signal,
• wherein a feature dimensionality of the high-frequency feature is lower than a feature dimensionality of the low-frequency feature;
• and
• encoding code configured to cause at least one of the at least one processor to perform quantization encoding on the low-frequency feature to obtain a low-frequency bitstream of the audio signal, and perform quantization encoding on the high-frequency feature to obtain a high-frequency bitstream of the audio signal.

A non-transitory computer-readable storage medium, storing computer code which, when executed by at least one processor, causes the at least one processor to at least:

• decompose an audio signal into a low-frequency subband signal and a high-frequency subband signal;
• perform convolution on the low-frequency subband signal to obtain a convolution feature of the low-frequency subband signal;
• perform pooling on the convolution feature to obtain a pooling feature of the low-frequency subband signal;
• obtain a low-frequency feature of the low-frequency subband signal based on the pooling feature of the low-frequency subband signal;
• obtain a high-frequency feature of the high-frequency subband signal,
• wherein a feature dimensionality of the high-frequency feature is lower than a feature dimensionality of the low-frequency feature;
• perform quantization encoding on the low-frequency feature to obtain a low-frequency bitstream of the audio signal;
• and
• perform quantization encoding on the high-frequency feature to obtain a high-frequency bitstream of the audio signal.