Scalable Decoding Apparatus and Scalable Encoding Apparatus

• US 20080126082A1
• Filed: 11/02/2005
• Published: 05/29/2008
• Est. Priority Date: 11/05/2004
• Status: Active Grant

• Current Assignee: III Holdings 12, LLC (Intellectual Ventures LLC)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Yoshida, Koji, Ehara, Hiroyuki, Oshikiri, Masahiro
• Granted Patent: US 7,983,904 B2
• Time in Patent Office: Days
• US Class Current: 704/205
• CPC Class Codes: G10L 19/24 Variable rate codecs, e.g. for generating different qualities using a scalable representation such as hierarchical encoding or layered encoding
• CPC Class Codes: G10L 21/038 using band spreading techniques

Abstract

A scalable decoding apparatus capable of providing decoded audio signals of high quality having less degradation of a high frequency spectrum even when decoding audio signals by generating the high frequency spectrum by use of a low frequency spectrum. In the apparatus, an amplitude adjusting part (1211) uses different adjustment coefficients in accordance with the characteristic of first layer spectrum information to adjust the amplitude of a first layer decoded signal spectrum, and then outputs the amplitude-adjusted first layer decoded signal spectrum to a pseudo-spectrum generating part (1012). Using amplitude-adjusted first layer decoded signal spectrum received from the amplitude adjusting part (1211), the pseudo-spectrum generating part (1012) generates and outputs a pseudo-spectrum of high frequencies to a scaling part (1013). The scaling part (1013) scales the spectrum received from the pseudo-spectrum generating part (1012) and then outputs it to an adder (B).

Claims

1. A scalable decoding apparatus comprising:

a first decoding section that decodes low frequency band coded information and obtains a low frequency band decoded signal; and

a second decoding section that obtains a high frequency band decoded signal from the low frequency band decoded signal and high frequency band coded information,

wherein the second decoding section comprises;

a transform section that transforms the low frequency band decoded signal and obtains a low frequency band spectrum;

an adjusting section that carries out amplitude adjustment on the low frequency band spectrum; and

a generating section that generates a high frequency band spectrum in a pseudo manner using the amplitude-adjusted low frequency band spectrum and the high frequency band coded information.

2. The scalable decoding apparatus according to claim 1, wherein the generating section carries out mirroring on the amplitude-adjusted low frequency band spectrum and generates the high frequency band spectrum in a pseudo manner.

3. The scalable decoding apparatus according to claim 1, wherein the generating section generates the high frequency band spectrum in a pseudo manner when at least part of the high frequency band coded information cannot be decoded.

4. The scalable decoding apparatus according to claim 1, wherein the generating section carries out pitch filtering processing on the amplitude-adjusted low frequency band spectrum and generates the high frequency band spectrum in a pseudo manner.

5. The scalable decoding apparatus according to claim 1, wherein the high frequency band coded information is configured in order of priority, that is, scale factor, amplitude adjustment coefficient, lag and residual spectrum, and the generating section generates the high frequency band spectrum in a pseudo manner using the scale factor, the amplitude adjustment coefficient and the lag when the residual spectrum is lost at the high frequency band coding information.

6. The scalable decoding apparatus according to claim 1, wherein the high frequency band coded information is configured in order of priority, in order of scale factor, amplitude adjustment coefficient, lag and residual spectrum, and the generating section carries out mirroring on the amplitude-adjusted low frequency band spectrum and generates the high frequency band spectrum in a pseudo manner when the lag and the residual spectrum are lost at the high frequency coding information.

7. The scalable decoding apparatus according to claim 1, wherein the high frequency band coded information is configured in order of priority, in order of scale factor, amplitude adjustment coefficient, lag and residual spectrum, and the generating section generates the high frequency band spectrum in a pseudo manner using past information corresponding to the lost information when at least one of the scale factor, the amplitude adjustment coefficient, the lag and the residual spectrum is lost.

8. A scalable encoding apparatus that generates low frequency band coded information and high frequency band coded information from an original signal to output to the scalable decoding apparatus according to claim 1, the scalable encoding apparatus comprising:

a first encoding section that encodes the original signal and obtains the low frequency band coded information; and

a second encoding section that obtains an estimation value of a high frequency band of a spectrum of the original signal using a filter having the low frequency band spectrum obtained from a decoded signal of the low frequency band coded information as an internal state, and outputs information indicating characteristics of the filter as the high frequency band coded information.