Unified speech/audio codec (USAC) windows sequence based mode switching
A Unified Speech and Audio Codec (USAC) that may process a window sequence based on mode switching is provided. The USAC may perform encoding or decoding by overlapping between frames based on a folding point when mode switching occurs. The USAC may process different window sequences for each situation to perform encoding or decoding, and thereby may improve a coding efficiency.
1. A signal processing method processed by a processor, comprising:
identifying a first window for a previous frame;
identifying a second window for a current frame;
modifying a left portion of the second window according to the first window, when a switching occurs between the previous frame and the current frame, and
processing the current frame by performing overlap-add operation between the previous frame applied to the first window and the current frame applied to the second window having the modified left portion,
wherein a slope of the left portion in the second window corresponding to an area for performing overlap-add operation with the first window is modified.
2. The signal processing method of claim 1 , wherein the overlap-add operation is performed at a folding point with respect to the first window and the second window.
3. The signal processing method of claim 1 , wherein the current frame is applied to a Linear Prediction Domain (LPD) mode and the previous frame is applied to a Frequency Domain (FD) mode.
4. The signal processing method of claim 1 , wherein the current frame is applied to a Linear Prediction Domain (LPD) mode and the previous frame is applied to the LPD mode.
5. The signal processing method of claim 1 , wherein the current frame is applied to Frequency Domain (FD) and the previous frame is applied to a Linear Prediction Domain (LPD) mode.
6. A signal processing method processed by a processor, comprising:
identifying a first window for a current frame;
identifying a second window for a next frame;
modifying a right portion of the first window according to the second window, when a switching occurs between the current frame and the next frame; and
processing the current frame by performing overlap-add operation between the current frame applied to the first window having the modified right portion and the next frame applied to the second window,
wherein a slope of the right portion in the first window corresponding to an area for performing the overlap-add operation with the second window is modified.
7. The signal processing method of claim 6 , wherein the overlap-add operation is performed at a folding point with respect to the first window and the first window.
8. The signal processing method of claim 6 , wherein the current frame is applied to a Linear Prediction Domain (LPD) mode and the next frame is applied to a Frequency Domain (FD) mode.
9. The signal processing method of claim 6 , wherein the current frame is applied to a Linear Prediction Domain (LPD) mode and the next frame is applied to the LPD mode.
10. The signal processing method of claim 6 , wherein the current frame is applied to Frequency Domain (FD) and the next frame is applied to a Linear Prediction Domain (LPD) mode.
11. A signal processing apparatus, comprising:
a processor is configured to:
identify a first window for a previous frame;
identify a second window for a current frame;
identify a third window for a next frame;
modify a left portion of the second window for the current frame according to the first window, when a switching occurs between the previous frame and the current frame;
modify a right portion of the second window for the current frame, according to the third window, when a switching occurs between the current frame and the next frame;
process the current frame by performing overlap-add operation between the previous frame applied to the first window and the current frame applied to the second window having the modified left portion or performing overlap-add operation between the current frame applied to the second window having the modified right portion and the next frame applied to the third window,
wherein a slope of the left portion in the second window corresponding to a first area for performing overlap-add operation with the first window is modified, or
wherein a slope of the right portion in the second window corresponding to a second area for performing the overlap-add operation with the third window is modified.
12. The signal processing apparatus of claim 11 , wherein the current frame is applied to one mode of a Linear Prediction Domain (LPD) mode or a Frequency Domain (FD) mode, and the previous frame is applied to one mode of the LPD mode or the FD mode.
13. The signal processing apparatus of claim 11 , wherein the current frame is applied to one mode of a Linear Prediction Domain (LPD) mode or a Frequency Domain (FD) mode, and the next frame is applied to one mode of the LPD mode or the FD mode.