ENCODING DEVICE, DECODING DEVICE, ENCODING METHOD AND DECODING METHOD

• US 20130035943A1
• Filed: 04/01/2011
• Published: 02/07/2013
• Est. Priority Date: 04/19/2010
• Status: Active Grant

• Current Assignee: Panasonic Intellectual Property Corporation of America (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: Yamanashi, Tomofumi, Oshikiri, Masahiro
• Granted Patent: US 9,508,356 B2
• Time in Patent Office: Days
• US Class Current: 704/500
• CPC Class Codes: G10L 19/038 Vector quantisation, e.g. TwinVQ audio
• 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 2019/0006 Tree or treillis structures; Delayed decisions

Abstract

Disclosed is an encoding device capable of improving decoded signal quality. A local search unit (302) conducts a local search on a plurality of sub-bands generated by dividing spectrum data, and calculates lattice vectors for the spectra in the plurality of sub-bands. A multi-rate indexing unit (303) uses the lattice vectors to perform multi-rate indexing on each of the sub-bands, and generates indexing information showing the results thereof. A band selection unit (304) determines certain sub-bands from amongst the plurality of sub-bands in a plurality of encoding layers as perceptually important sub-band groups, where these are: within a selection range of sub-bands wherein the total number of encoding bits allocated to each of the plurality of sub-bands in the indexing information is equal to or less than an already set value, and within a sub-band selection range with the highest total energy of each of the plurality of sub-bands.

Claims

1. A coding apparatus that includes a plurality of coding layers for performing coding processes together, the coding apparatus comprising:

a searching section that divides spectrum data inputted to the plurality of coding layers to generate a plurality of subbands, and performs a neighborhood search for the plurality of subbands to calculate lattice vectors for the spectra of the plurality of subbands;

a coding section that performs multi-rate indexing for each of the plurality of subbands using a corresponding one of the lattice vectors, to generate index information indicating a result of the multi-rate indexing for each of the plurality of subbands; and

a selecting section that determines a selection range of subbands as a specific subband group in the plurality of coding layers using the number of coding bits assigned to each of the plurality of subbands in the index information and a subband energy which is an energy of each of the plurality of subbands, the selection range of subbands being a range in which a total number of the coding bits is equal to or less than a preset value and a total of the subband energies is the highest among the plurality of subbands.

2. The coding apparatus according to claim 1, further comprising an adjusting section that rearranges the index information such that a part corresponding to the specific subband group in the index information is located at the top of the index information.

3. The coding apparatus according to claim 1, wherein the selecting section determines the selection range which is the specific subband group from the plurality of subbands, using a weighting factor such that a subband which is closer to a subband selected as the specific subband group in a previous frame is likely to be selected as the specific subband group in a current frame.

4. The coding apparatus according to claim 1, wherein the selecting section determines the selection range which is the specific subband group from the plurality of subbands, using the number of bits used for the multi-rate indexing for each of the plurality of subbands as the number of coding bits assigned to each of the plurality of subbands.

5. The coding apparatus according to claim 1, wherein the selecting section determines the selection range which is the specific subband group from the plurality of subbands, using a preset fixed number of bits as the number of coding bits assigned to each of the plurality of subbands.

6. The coding apparatus according to claim 1, wherein the selecting section determines the selection range which is the specific subband group from the plurality of subbands, using only a subband having a subband energy equal to or more than a threshold among the plurality of subbands.

7. The coding apparatus according to claim 1, wherein the selecting section determines the selection range which is the specific subband group from the plurality of subbands generated by dividing spectrum data acquired by linking the top and end of the spectrum data and then rotating the spectrum data.

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

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

10. A decoding apparatus that decodes a signal from a coding apparatus including a plurality of coding layers for performing coding processes together, the decoding apparatus comprising:

a receiving section that receives index information and band information which are generated in the coding apparatus, the index information indicating a result of multi-rate indexing for each of a plurality of subbands generated by dividing spectrum data inputted to the plurality of coding layers, using a lattice vector acquired by a neighborhood search for the plurality of subbands, band information indicating a specific subband group which is a selection range of subbands and being determined using coding bits assigned to each of the plurality of subbands and a subband energy which is an energy of each of the plurality of subbands, the selection range of subbands being a range in which a total number of coding bits assigned to each of the plurality of subbands in the multi-rate indexing is equal to or less than a preset value and a total of subband energies which are the energies of the plurality of subbands is the highest among the plurality of subbands; and

a decoding section that decodes only a part corresponding to the specific subband group indicated by the band information, in the index information, to generate a decoded signal when a decoding process is performed in only part of the plurality of coding layers.

11. The decoding apparatus according to claim 10, wherein the receiving section receives the index information which is rearranged such that a part corresponding to the specific subband group is located at the top of the index information in the coding apparatus, the decoding apparatus further comprising an adjusting section that performs a rearrangement process which is reversal of a rearrangement process in the coding apparatus on the index information when the decoding process is performed in the plurality of coding layers and that does not perform the rearrangement process on the index information when the decoding process is performed in only a part of the plurality of coding layers.

12. A communication terminal apparatus comprising the decoding apparatus according to claim 10.

13. A base station apparatus comprising the decoding apparatus according to claim 10.

14. A coding method in a coding apparatus including a plurality of coding layers for performing coding processes together, the coding method comprising:

a searching step of dividing spectrum data inputted to the plurality of coding layers to generate a plurality of subbands, and performing a neighborhood search for the plurality of subbands to calculate lattice vectors for the spectra of the plurality of subbands;

a coding step of performing multi-rate indexing for each of the plurality of subbands using a corresponding one of the lattice vectors, to generate index information indicating a result of the multi-rate indexing for each of the plurality of subbands; and

a selecting step of determining a selection range of subbands as a specific subband group in the plurality of coding layers using the number of coding bits assigned to each of the plurality of subbands in the index information and a subband energy which is an energy of each of the plurality of subbands, the selection range of subbands being a range in which a total number of the coding bits is equal to or less than a preset value and a total of the subband energies is the highest among the plurality of subbands.

15. A decoding method in a decoding apparatus that decodes a signal from a coding apparatus including a plurality of coding layers for performing coding processes together, the decoding method comprising:

a receiving step of receiving index information and band information which are generated in the coding apparatus, the index information indicating a result of multi-rate indexing for each of a plurality of subbands generated by dividing spectrum data inputted to the plurality of coding layers, using a lattice vector acquired by a neighborhood search for the plurality of subbands, band information indicating a specific subband group which is a selection range of subbands and being determined using coding bits assigned to each of the plurality of subbands and a subband energy which is an energy of each of the plurality of subbands, the selection range of subbands being a range in which a total number of coding bits assigned to each of the plurality of subbands in the multi-rate indexing is equal to or less than a preset value and a total of subband energies which are energies of the plurality of subbands is the highest among the plurality of subbands; and

a decoding step of decoding only part corresponding to the specific subband group indicated by the band information, in the index information, to generate a decoded signal when a decoding process is performed in only part of the plurality of coding layers.