Method of generating residual signal, and encoder and decoder performing the method

A method of generating a residual signal performed by a decoder, the method comprising:

• unpacking a bitstream received from an encoder;
• dequantizing a third residual signal extracted from the unpacked bitstream;
• determining a second residual signal transformed into a frequency domain from the dequantized third residual signal, using frequency-domain prediction (FDP) decoding, wherein an information amount of the second residual signal is less than that of the dequantized third residual signal;
• transforming the second residual signal transformed into the frequency domain into a time domain;
• and
• generating a first residual signal having a greater information amount than the second residual signal, by inversely transforming a second residual signal transformed into the time domain.

An encoder performing a method of generating a residual signal, the encoder comprising:

• a processor,
• wherein the processor is configured to:
• identify an input signal comprising an audio sample;
• generate a first residual signal from the input signal using linear predictive coding (LPC);
• generate a second residual signal having a less information amount than the first residual signal by transforming the first residual signal;
• transform the second residual signal into a frequency domain;
• and
• generate a third residual signal having a less information amount than the second residual signal from the transformed second residual signal, using frequency-domain prediction (FDP) encoding.