Alias cancelling during audio coding mode transitions

• US 9,214,160 B2
• Filed: 08/06/2013
• Issued: 12/15/2015
• Est. Priority Date: 07/27/2009
• Status: Expired

• 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:
  US13/960,284
• Publication Number:
  US 20130325487A1
• Time in Patent Office: 861 Days
• Field of Search: 704/200, 704/201, 704/200.1, 704/211
• 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, an audio signal including a first data of a first block encoded with a rectangular coding scheme and a second data of a second block encoded with a non-rectangular coding scheme;

generating an output signal for the first block using the first data of the first block based on the rectangular coding scheme;

receiving a compensation signal corresponding to the second block;

obtaining a prediction of an aliasing part by applying a window of the second block to the output signal for the first block; and

obtaining a reconstructed signal for the second block based on the second data, the compensation signal and the prediction of the aliasing part,

wherein, when the first data is encoded with a LPD (Linear Prediction Domain) coding scheme and the window of the second block belongs to a transition window class, the window of the second block has an ascending line with a first slope,

wherein the first slope is gentler than a second slope.

2. The method of claim 1, wherein, when the first data is encoded with a FD (Frequency Domain) coding scheme and the window of the second block belongs to the transition window class, the window of the second block has an ascending line with the second slope.

3. The method of claim 1, wherein, when the transition window class comprises a long_stop window and a stop_start window, and

the long_stop window and the stop_start window have horizontal-asymmetry, and have a zero part in a left half.

4. The method of claim 1, wherein the compensation signal is received, when the first data is encoded with the rectangular coding scheme.

5. The method of claim 1, wherein the compensation signal is generated based on at least one of a difference related to asymmetry between a rectangular window and a non-rectangular window, and a difference between the aliasing part and a prediction of the aliasing part.

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

a de-multiplexer receiving an audio signal including a first data of a first block encoded with a rectangular coding scheme and a second data of a second block encoded with a non-rectangular coding scheme, and receiving a compensation signal corresponding to the second block;

a rectangular decoding unit generating an output signal for the first block using the first data of the first block based on the rectangular coding scheme, and obtaining a prediction of an aliasing part by applying a window of the second block to the output signal for the first block; and

a non-rectangular decoding unit obtaining a reconstructed signal for the second block based on the second data, the compensation signal and the prediction of the aliasing part,

wherein, when the first data is encoded with a LPD (Linear Prediction Domain) coding scheme and the window of the second block belongs to a transition window class, the window of the second block has an ascending line with a first slope,

wherein the first slope is gentler than a second slope.

7. The apparatus of claim 6, wherein, when the first data is encoded with a FD (Frequency Domain) coding scheme and the window of the second block belongs to the transition window class, the window of the second block has an ascending line with the second slope.

8. The apparatus of claim 6, wherein, when the transition window class comprises a long_stop window and a stop_start window, and

the long_stop window and the stop_start window have horizontal-asymmetry, and have a zero part in a left half.

9. The apparatus of claim 6, wherein the compensation signal is received, when the first data is encoded with the rectangular coding scheme.

10. The apparatus of claim 6, wherein the compensation signal is generated based on at least one of a difference related to asymmetry between a rectangular window and a non-rectangular window, and a difference between the aliasing part and a prediction of the aliasing part.