Unified speech/audio codec (USAC) windows sequence based mode switching

• US 10,622,001 B2
• Filed: 05/15/2018
• Issued: 04/14/2020
• Est. Priority Date: 11/26/2008
• Status: Active Grant

• Current Assignee: Electronics and Telecommunications Research Institute
• Original Assignee: Electronics and Telecommunications Research Institute
• Inventors: Beack, Seungkwon, Lee, Tae Jin, Kim, Min Je, Kang, Kyeongok, Jang, Dae Young, Seo, Jeongil, Hong, Jin Woo, Ahn, Chieteuk, Park, Ho Chong, Park, Young-cheol
• Primary Examiner(s): Azad, Abul K
• Application Number:
  US15/980,012
• Publication Number:
  US 20180261235A1
• Time in Patent Office: 700 Days
• Field of Search: None
• CPC Class Codes: G10L 19/022 Blocking, i.e. grouping of samples in time; Choice of analysis windows; Overlap factoring
• CPC Class Codes: G10L 19/06 Determination or coding of the spectral characteristics, e.g. of the short-term prediction coefficients
• CPC Class Codes: G10L 19/18 Vocoders using multiple modes
• CPC Class Codes: G10L 19/22 Mode decision, i.e. based on audio signal content versus external parameters

Abstract

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.

Claims

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.