ENCODING DEVICE AND ENCODING METHOD

• US 20110035214A1
• Filed: 04/08/2009
• Published: 02/10/2011
• Est. Priority Date: 04/09/2008
• Status: Abandoned Application

• Current Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: Morii, Toshiyuki
• Application Number:
  US12/936,447
• Publication Number:
  US 20110035214A1
• Time in Patent Office: Days
• US Class Current: 704/225
• CPC Class Codes: G10L 19/038 Vector quantisation, e.g. TwinVQ audio
• CPC Class Codes: G10L 19/10 the excitation function being a multipulse excitation
• 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

Good sound quality as perceived by the ear is obtained even with few information bits. A shape quantizer (111) is comprised of an interval search unit (121) which searches and encodes the pulses in each band of a plurality of divisions of the specified search interval, and a full search unit (122) which searches for pulses over the entire search interval, and quantizes the shape of the input spectrum at the positions and the polarities of a small number of pulses. The interval search unit (121) encodes a pulse searched for in a higher band than the specified frequency with fewer bits than a pulse searched for in another band. The full search unit (122) encodes the pulses positioned in a higher band than the specified frequency with fewer bits than the other pulses. A gain quantizer (112) calculates and quantizes in each band the gain of a pulse searched for by the shaper quantizer (111).

Claims

1. A coding apparatus comprising:

a shape quantizing section that encodes a shape of a frequency spectrum; and

a gain quantizing section that encodes a gain of the frequency spectrum,

wherein the shape quantizing section comprises;

an interval search section that searches for a first waveform in each of a plurality of bands dividing a predetermined search interval, and

encodes the first waveform searched out in a predetermined band, by a smaller number of bits than other first waveforms; and

a thorough search section that searches for a second waveform over the predetermined search interval, and, when the second waveform located in the predetermined band satisfies a predetermined condition, encodes a position near a position of the second waveform located in the predetermined band.

2. The coding apparatus according to claim 1, wherein the thorough search section searches for the second waveform while evaluating a coding distortion by a band-specific ideal gain.

3. The coding apparatus according to claim 1, wherein the thorough search section calculates a plurality of values using a plurality of items of position information related to the second waveform, and encodes position information related to the second waveform using the plurality of values.

4. The coding apparatus according to claim 1, wherein the thorough search section encodes position information of the second waveform located in the predetermined band, such that positions before and after the first waveform searched out in the predetermined band can be distinguished.

5. The coding apparatus according to claim 1, wherein the gain quantizing section calculates and encodes gains of the first waveform and the second waveform on a per band basis.

6. The coding apparatus according to claim 1, wherein the interval search section performs a search at fractional accuracy in a low frequency band among the plurality of bands dividing the predetermined search interval, and encodes position information showing a position of the fractional accuracy in a searched waveform by a position of integral accuracy closest to the position of the fractional accuracy.

7. The coding apparatus according to claim 6, wherein the gain quantizing section encodes a gain of a waveform in the position of the fractional accuracy of the searched waveform.

8. A coding method comprising:

a shape quantizing step of encoding a shape of a frequency spectrum; and

a gain quantizing step of encoding a gain of the frequency spectrum,

wherein the shape quantizing step comprises;

an interval search step of searching for a first waveform in each of a plurality of bands dividing a predetermined search interval, and encoding the first waveform searched out in a predetermined band, by a smaller number of bits than other first waveforms; and

a thorough search step of searching for a second waveform over the predetermined search interval, and, when the second waveform located in the predetermined band satisfies a predetermined condition, encodes a position nearby a position of the second waveform located in the predetermined band.