Unified speech/audio codec (USAC) processing 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 method of processing a window sequence to perform encoding or decoding by a processor, comprising:
determining a first window for a previous block;
determining a second window for a current block;
modifying a left portion of a second window for the current block based on the first window, when a switching occurs from the previous block to the current block; and
processing the current block using the modified second window by performing overlap-add operation between the previous block applied to the first window and the current block applied to the second window having the modified left portion,
wherein a slope of the left portion in the second window is modified according to the first window,
wherein the slope corresponds to an area for performing overlap-add operation with the first window.
2. The method of claim 1 , wherein the modifying comprising:
modifying a shape of the left portion of the second window according to the first window.
3. The method of claim 1 , wherein the modifying comprising:
modifying a size of the left portion of the second window according to the first window.
4. The method of claim 1 , wherein the current block is a Linear Prediction Domain (LPD) mode and the previous block is the LPD mode.
5. The method of claim 1 , wherein the current block is a Frequency Domain (FD) mode and the previous block is a Linear Prediction Domain (LPD) mode.
6. The method of claim 1 , wherein the current block is a Linear Prediction Domain (LPD) mode and the previous block is a Frequency Domain (FD) mode.
7. A method of processing a window sequence to perform encoding or decoding by a processor, comprising:
determining a first window for a current block;
determining a second window for a next block;
modifying a right portion of a first window for the current block based on the second window, when a block switching occurs from the current block to the next block; and
processing the current block using the modified first window by performing overlap-add operation between the current block applied to the first window having the modified right portion and the next block applied to the second window,
wherein a slope of the right portion in the first window is modified according to the second window,
wherein the slope corresponds to an area for performing overlap-add operation with the second window.
8. The method of claim 7 , wherein the modifying comprising:
modifying a shape of the right portion of the first window based on the second window.
9. The method of claim 7 , wherein the modifying comprising:
modifying a size of the right portion of the first window based on the second window.
10. The method of claim 7 , wherein the current block is a Linear Prediction Domain (LPD) mode and the previous block is the LPD mode.
11. The method of claim 7 , wherein the current block is a Frequency Domain (FD) mode and the previous block is a Linear Prediction Domain (LPD) mode.
12. The method of claim 7 , wherein the current block is a Linear Prediction Domain (LPD) mode and the previous block is a Frequency Domain (FD) mode.
13. A device for processing a window sequence to perform encoding or decoding, comprising:
one or more processor configured to:
determine a first window for a previous block;
determine a second window for a current block;
modify a left portion of a second window for the current block based on the first window, when a switching occurs from the previous block to the current block; and
process the current block using the modified second window by performing overlap-add operation between the previous block applied to the first window and the current block applied to the second window having the modified left portion,
wherein a slope of the left portion in the second window is modified according to the first window,
wherein the slope corresponds to an area for performing overlap-add operation with the first window.
14. The device of claim 13 , wherein the processor modifies a shape of the left portion of the second window according to the first window, or
the processor modifies a size of the left portion of the second window according to the first window.
15. The device of claim 13 , wherein the current block is a Linear Prediction Domain (LPD) mode and the previous block is the LPD mode.
16. The device of claim 13 , wherein the current block is a Frequency Domain (FD) mode and the previous block is a Linear Prediction Domain (LPD) mode.
17. The device of claim 13 , wherein the current block is a Linear Prediction Domain (LPD) mode and the previous block is a Frequency Domain (FD) mode.