Audio signal encoding and decoding method using a neural network model to generate a quantized latent vector, and encoder and decoder for performing the same

An encoder for performing a method of encoding an audio signal using a neural network model, the encoder comprising:

• a processor configured to identify an input signal, generate a quantized latent vector by inputting the input signal to the neural network model encoding the input signal, and generate a bitstream corresponding to the quantized latent vector,
• wherein the neural network model comprises i) a feature extraction layer generating a latent vector by extracting a feature of the input signal, ii) a plurality of downsampling blocks producing a plurality of downsampled latent vector corresponding to downsamplings of the latent vector respectively, and iii) a plurality of quantization blocks performing quantization of the plurality of downsampled latent vectors respectively, and
• wherein each of the plurality of quantization blocks comprises a conversion layer converting the respective downsampled latent vector to produce a respective converted latent vector, and a vector quantization layer performing vector quantization on the respective converted latent vector based on a codebook.