Method of encoding and decoding audio signal and encoder and decoder performing the method

A method of decoding an audio signal performed by a decoder, the method comprising:

• extracting a quantized linear prediction coefficient and a quantized residual signal from a bitstream received from an encoder;
• generating a temporal envelope by dequantizing the quantized linear prediction coefficient;
• and
• reconstructing an audio signal from the quantized residual signal using the temporal envelope.

An encoder configured to perform a method of encoding an audio signal, the encoder comprising:

• a processor,
• wherein the processor is configured to:
• identify a time-domain audio signal in a unit of blocks;
• quantize a linear prediction coefficient extracted from a combined block in which a current original block of the audio signal and a previous original block chronologically adjacent to the current original block are combined, using frequency-domain linear predictive coding (LPC);
• generate a temporal envelope by dequantizing the quantized linear prediction coefficient;
• extract a residual signal from the combined block based on the temporal envelope;
• quantize the residual signal using one of time-domain quantization and frequency-domain quantization;
• and
• transform the quantized residual signal and the quantized linear prediction coefficient into a bitstream.