LPC residual signal encoding/decoding apparatus of modified discrete cosine transform (MDCT)-based unified voice/audio encoding device
Disclosed is an LPC residual signal encoding/decoding apparatus of an MDCT based unified voice and audio encoding device. The LPC residual signal encoding apparatus analyzes a property of an input signal, selects an encoding method of an LPC filtered signal, and encode the LPC residual signal based on one of a real filterbank, a complex filterbank, and an algebraic code excited linear prediction (ACELP).
1. A processing method performed by a device, comprising:
identifying a previous frame which has a speech characteristic to be coded in a time domain;
identifying a current frame which has an audio characteristic to be coded in a frequency domain; and
overlap-adding a first signal related to the previous frame and a second signal related to the current frame for time domain aliasing cancellation (TDAC), when a switching occurs from the previous frame to the current frame,
wherein the first signal is windowed previous frame modified based on an artificial TDA (time domain aliasing) signal, and the second signal is windowed current frame,
wherein the artificial TDA signal is used to compensate for a distortion between the first signal and the second signal.
2. The processing method of claim 1 , wherein a left portion of the second signal is determined based on a sine window.
3. The processing method of claim 1 , wherein the previous frame is coded with CELP (code-excited linear prediction), and the current frame is coded with MDCT (Modified Discrete Cosine Transform).
4. A processing method performed by a device, comprising:
identifying a previous frame which has a speech characteristic to be coded in CELP (code-excited linear prediction);
identifying a current frame which has an audio characteristic to be coded in MDCT (Modified Discrete Cosine Transform); and
generating a first signal by applying a first window into the previous frame, and a second signal by applying a second window into the current frame,
processing overlap-adding the first signal and the second signal, when a switching occurs from the previous frame to the current frame,
wherein the first signal is determined based on an artificial TDA (time domain aliasing) signal,
wherein the artificial TDA signal is used to cancel an aliasing introduced by the MDCT.
5. The processing method of claim 4 , wherein a left portion of the second signal is determined based on a sine window.