SCALABLE ENCODING APPARATUS, SCALABLE DECODING APPARATUS, AND METHODS THEREOF

• US 20090125300A1
• Filed: 10/26/2005
• Published: 05/14/2009
• Est. Priority Date: 10/28/2004
• Status: Active Grant

• Current Assignee: III Holdings 12, LLC (Intellectual Ventures LLC)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Oshikiri, Masahiro
• Granted Patent: US 8,019,597 B2
• Time in Patent Office: Days
• US Class Current: 704/207
• 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 19/09 Long term prediction, i.e. removing periodical redundancies, e.g. by using adaptive codebook or pitch predictor
• 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

Abstract

A scalable encoding apparatus capable of reducing the bit rates of encoded parameters and also capable of efficiently encoding even audio signals in which a plurality of harmonic structures are coexistent. In the apparatus, an MDCT analyzing part (111) MDCT analyzes an audio signal (S15) for converting/encoding processes. A pitch frequency converting part (112) determines the inverse of a pitch period to calculate a pitch frequency. A selecting part (113) selects spectra located at frequencies that are integral multiples of the pitch frequency. A second layer encoding part (106) encodes the selected spectra.

Claims

1. A scalable coding apparatus comprising:

a first coding section that encodes a speech signal using a pitch period of the speech signal;

a calculation section that calculates a pitch frequency from the pitch period; and

a second coding section that encodes a spectrum of a frequency of an integral multiple of the pitch frequency in spectra of the speech signal.

2. The scalable coding apparatus according to claim 1, further comprising a third coding section that, when the spectra of the speech signal comprise a plurality of pitch frequencies, using another pitch frequency that is different from the pitch frequency used in the second coding section, encodes a spectrum at a frequency of an integral multiple of said another pitch frequency.

3. The scalable coding apparatus according to claim 2, wherein the third coding section further encodes a difference between said another pitch frequency and the pitch frequency used in the second coding section.

4. The scalable coding apparatus according to claim 1, wherein the calculation section acquires the pitch period from a decoded signal of an encoded parameter obtained in the first coding section and calculates the pitch frequency.

5. The scalable coding apparatus according to claim 1, wherein the second coding section encodes a spectrum of a higher frequency than a predetermined frequency in the spectra of the speech signal.

6. The scalable coding apparatus according to claim 5, wherein the second coding section further encodes information related to the predetermined frequency.

7. The scalable coding apparatus according to claim 1, further comprising a correction section that corrects the pitch period based on a nearby pitch period of the pitch period,

wherein the calculation section calculates the pitch frequency from the corrected pitch period.

8. The scalable coding apparatus according to claim 7, wherein the second coding section further encodes a difference between the pitch period and the corrected pitch period.

9. The scalable coding apparatus according to claim 1, wherein the second coding section performs encoding using modified discrete cosine transform.

10. The scalable coding apparatus according to claim 1, wherein said spectrum at a frequency of an integral multiple of the pitch frequency is a spectrum having a predetermined bandwidth.

12. A communication terminal apparatus comprising the scalable coding apparatus according to claim 1.

14. A base station apparatus comprising the scalable coding apparatus according to claim 1.

11. A scalable decoding apparatus comprising:

a first decoding section that decodes a first encoded parameter of a speech signal that is encoded using a pitch period of the speech signal, using the pitch period;

a calculation section that calculates a pitch frequency from the pitch period;

a generation section that generates a spectrum of part of spectra of the speech signal from a second encoded parameter that is obtained by encoding said spectrum of part of the spectra of the speech signal; and

an arrangement section that arranges the spectrum generated by the generation section at a frequency of an integral multiple of the pitch frequency calculated by the calculation section.

13. A communication terminal apparatus comprising the scalable decoding apparatus according to claim 11.

15. A base station apparatus comprising the scalable decoding apparatus according to claim 11.

16. A scalable coding method comprising the steps of:

encoding a speech signal using a pitch period of the speech signal;

calculating a pitch frequency from the pitch period; and

encoding a spectrum of a frequency of an integral multiple of the pitch frequency in spectra of the speech signal.

17. A scalable decoding method comprising the steps of:

decoding a first encoded parameter of a speech signal that is encoded using a pitch period of the speech signal, using the pitch period;

calculating a pitch frequency from the pitch period;

generating a spectrum of part of spectra of the speech signal from a second encoded parameter that is obtained by encoding said spectrum of part of the spectra of the speech signal; and

arranging the generated spectrum at a frequency of an integral multiple of the calculated pitch frequency.