Method and apparatus for processing an audio signal using window transitions for coding schemes

• US 9,082,399 B2
• Filed: 08/06/2013
• Issued: 07/14/2015
• Est. Priority Date: 07/27/2009
• Status: Active Grant

• Current Assignee: Dolby Laboratories Licensing Corporation (Dolby Laboratories Incorporated)
• Original Assignee: Industry Academic Cooperation Foundation
• Inventors: Oh, Hyen-O, Lee, Chang Heon, Kang, Hong Goo, Song, Jung Wook
• Primary Examiner(s): PULLIAS, JESSE SCOTT
• Application Number:
  US13/960,220
• Publication Number:
  US 20130332149A1
• Time in Patent Office: 707 Days
• Field of Search: 704200-256, 704500-504
• US Class Current: 1/1
• CPC Class Codes: G10L 19/005 Correction of errors induced by the transmission channel, if related to the coding algorithm
• CPC Class Codes: G10L 19/022 Blocking, i.e. grouping of samples in time; Choice of analysis windows; Overlap factoring
• CPC Class Codes: G10L 19/04 using predictive techniques
• CPC Class Codes: G10L 19/18 Vocoders using multiple modes
• CPC Class Codes: G10L 25/45 characterised by the type of analysis window

Abstract

An apparatus for processing an audio signal and method thereof are disclosed. The present invention includes receiving, by an audio processing apparatus, an audio signal including a first data of a first block encoded with rectangular coding scheme and a second data of a second block encoded with non-rectangular coding scheme; receiving a compensation signal corresponding to the second block; estimating a prediction of an aliasing part using the first data; and, obtaining a reconstructed signal for the second block based on the second data, the compensation signal and the prediction of aliasing part.

Claims

1. A method for processing an audio signal, comprising:

receiving, by an audio processing apparatus, coding identification information indicating whether to apply a first coding scheme or a second coding scheme to a current frame of the audio signal,

when the coding identification information indicates that the second coding scheme is applied to the current frame, receiving window type information indicating a particular window for the current frame, from among a plurality of windows;

applying a current window to the current frame based on the window type information,

wherein, when the first coding scheme is applied to a previous frame, the current window is determined to be one of a short window, a long stop window, or a stop start window,

wherein the long stop window and the stop start window have an ascending line which width is N/4, the long stop window has a descending line which width is N, and the stop start window has a descending line which width is N/8,

and wherein the N is the frame length.

2. The method of claim 1, wherein the length of the short window, the long stop window, and the stop start window is 2N.

3. The method of claim 1, wherein the length of the short window, the long stop window, and the stop start window corresponds to 2048 samples.

4. The method of claim 1, wherein a cross point between the current window and a previous window is at N/2 distance from the start of the current window.

5. The method of claim 1, wherein the long stop window has a zero part in a right half, and

wherein the stop start window has no zero part in a right half.

6. The method of claim 1, wherein a cross point between the current window and a following window is at 3N/2 distance from the start of the current window.

7. The method of claim 1, wherein the first coding scheme is based on the linear-prediction domain, and the second coding scheme is based on the frequency-domain.

8. An apparatus for processing an audio signal, comprising:

a de-multiplexer receiving, by an audio processing apparatus, coding identification information indicating whether to apply a first coding scheme or a second coding scheme to a current frame of the audio signal, and, when the coding identification information indicates that the second coding scheme is applied to the current frame, receiving window type information indicating a particular window for the current frame, from among a plurality of windows;

a second coding unit applying a current window to the current frame based on the window type information, wherein, when the first coding scheme is applied to a previous frame, the current window is determined to be one of a short window, a long stop window, or a stop start window,

wherein the long stop window and the stop start window have an ascending line which width is N/4, the long stop window has a descending line which width is N, and the stop start window has a descending line which width is N/8,

and wherein the N is frame length.

9. The apparatus of claim 8, wherein the length of the short window, the long stop window, and the stop start window is 2N.

10. The apparatus of claim 8, wherein length of the short window, the long stop window, and the stop start window corresponds to 2048 samples.

11. The apparatus of claim 8, wherein a cross point between the current window and a previous window is at N/2 distance from start of the current window.

12. The apparatus of claim 8, wherein the long stop window has a zero part in a right half, and

wherein the stop start window has no zero part in a right half.

13. The apparatus of claim 8, wherein a cross point between the current window and a following window is at 3N/2 distance from start of the current window.

14. The apparatus of claim 8, wherein the first coding scheme is based on the linear-prediction domain, and the second coding scheme is based on the frequency-domain.