Method and apparatus for encoding/decoding audio signal

1 . An encoding method, comprising:

transforming an input audio signal in a time domain into an audio signal in a frequency domain;

quantizing energy of a frequency band of the audio signal in the frequency domain;

generating a normal signal by normalizing the audio signal in the frequency domain according to quantized energy;

obtaining a feature vector including information on the energy of the frequency band based on the normal signal and the input audio signal;

quantizing the feature vector;

obtaining a scale factor used to scale the normal signal based on a quantized feature vector;

quantizing an adjustment signal into which the normal signal has been scaled based on the scale factor; and

outputting bitstreams based on the quantized energy, the quantized feature vector, and a quantized adjustment signal,

wherein the obtaining of the scale factor comprises obtaining the scale factor for each frequency band based on the quantized feature vector,

wherein a number of dimensions of the scale factor matches a total number of bands in the frequency band, and

wherein a number of dimensions of the quantized feature vector matches a number of dimensions of the feature vector.

2 . The encoding method of claim 1 , wherein the obtaining of the feature vector comprises:

obtaining a magnitude spectrum of the input audio signal in a frequency domain based on the input audio signal; and

obtaining the feature vector based on the magnitude spectrum and the normal signal.

3 . The encoding method of claim 2 , wherein the obtaining of the feature vector further comprises:

generating a latent representation for extracting the information on the energy of the frequency band based on the magnitude spectrum and the normal signal; and

calculating the feature vector based on the latent representation.

4 . The encoding method of claim 1 , wherein the quantizing of the adjustment signal comprises:

generating the adjustment signal by scaling the normal signal according to the scale factor.

5 . The encoding method of claim 1 , wherein the outputting of the bitstreams comprises:

outputting a first bitstream by encoding the quantized feature vector;

outputting a second bitstream by encoding the quantized adjustment signal; and

outputting a third bitstream by encoding the quantized energy.

6 . A decoding method, comprising:

receiving bitstreams from an encoder;

obtaining a scale factor used to inversely scale a restored adjustment signal based on a first bitstream into which a quantized feature vector is encoded;

generating a restored normal signal based on the scale factor and a second bitstream into which a quantized adjustment signal is encoded;

obtaining a restored audio signal in a frequency domain based on a third bitstream, into which quantized energy is encoded, and the restored normal signal; and

outputting a restored audio signal in a time domain based on the restored audio signal in the frequency domain,

wherein a number of dimensions of the scale factor matches a total number of bands in the frequency band, and

wherein a number of dimensions of the quantized feature vector matches a number of dimensions of the feature vector.

7 . The decoding method of claim 6 , wherein the obtaining of the scale factor comprises:

obtaining a quantized feature vector by decoding the first bitstream; and

calculating the scale factor from the quantized feature vector.

8 . The decoding method of claim 6 , wherein the generating of the restored normal signal comprises:

generating a restored adjustment signal by decoding the second bitstream; and

inversely scaling the restored adjustment signal according to the scale factor.

9 . The decoding method of claim 6 , wherein the obtaining of the restored audio signal in the frequency domain comprises:

outputting restored energy of a frequency band of the restored audio signal in the frequency domain, based on the third bitstream; and

denormalizing the restored normal signal according to the restored energy.

10 . An encoding device, comprising:

a memory configured to store one or more instructions; and

a processor configured to execute the instructions,

wherein, when the instructions are executed, the processor is configured to perform a plurality of operations, and

wherein the plurality of operations comprises:

transforming an input audio signal in a time domain into an audio signal in a frequency domain;

quantizing energy of a frequency band of the audio signal in the frequency domain;

generating a normal signal by normalizing the audio signal in the frequency domain according to quantized energy;

obtaining a feature vector including information on the energy of the frequency band based on the normal signal and the input audio signal;

quantizing the feature vector;

obtaining a scale factor used to scale the normal signal based on a quantized feature vector;

quantizing an adjustment signal into which the normal signal has been scaled based on the scale factor; and

outputting bitstreams based on the quantized energy, the quantized feature vector, and a quantized adjustment signal,

wherein the obtaining of the scale factor comprises obtaining the scale factor for each frequency band based on the quantized feature vector,

wherein a number of dimensions of the scale factor matches a total number of bands in the frequency band, and

wherein a number of dimensions of the quantized feature vector matches a number of dimensions of the feature vector.

11 . The encoding device of claim 10 , wherein the obtaining of the feature vector comprises:

obtaining a magnitude spectrum of the input audio signal in a frequency domain based on the input audio signal; and

obtaining the feature vector based on the magnitude spectrum and the normal signal.

12 . The encoding device of claim 11 , wherein the obtaining of the feature vector further comprises:

generating a latent representation for extracting the information on the energy of the frequency band based on the magnitude spectrum and the normal signal; and

calculating the feature vector based on the latent representation.

13 . The encoding device of claim 10 , wherein the quantizing of the adjustment signal comprises:

generating the adjustment signal by scaling the normal signal according to the scale factor.

14 . The encoding device of claim 10 , wherein the outputting of the bitstreams comprises:

outputting a first bitstream by encoding the quantized feature vector;

outputting a second bitstream by encoding the quantized adjustment signal; and

outputting a third bitstream by encoding the quantized energy.