IMAGE DECODING APPARATUS AND IMAGE CODING APPARATUS

• US 20110200115A1
• Filed: 06/05/2009
• Published: 08/18/2011
• Est. Priority Date: 06/10/2008
• Status: Active Grant

• Current Assignee: Sovereign Peak Ventures, LLC (Dominion Harbor Enterprises, LLC)
• Original Assignee: Panasonic Intellectual Property Management Co., Ltd. (Panasonic Holdings Corporation)
• Inventors: Iguchi, Masayasu, Hayashi, Yoshiteru, Amano, Hiroshi
• Granted Patent: US 9,042,457 B2
• Time in Patent Office: Days
• US Class Current: 375/240.24
• CPC Class Codes: H04N 19/124 Quantisation
• CPC Class Codes: H04N 19/13 Adaptive entropy coding, e.g. adaptive variable length coding [AVLC] or context adaptive binary arithmetic coding [CABAC]
• CPC Class Codes: H04N 19/132 Sampling, masking or truncation of coding units, e.g. adaptive resampling, frame skipping, frame interpolation or high-frequency transform coefficient masking
• CPC Class Codes: H04N 19/134 characterised by the element, parameter or criterion affecting or controlling the adaptive coding
• CPC Class Codes: H04N 19/147 according to rate distortion criteria rate-distortion as a criterion for motion estimation H04N19/567
• CPC Class Codes: H04N 19/174 the region being a slice, e.g. a line of blocks or a group of blocks
• CPC Class Codes: H04N 19/176 the region being a block, e.g. a macroblock
• CPC Class Codes: H04N 19/40 using video transcoding, i.e. partial or full decoding of a coded input stream followed by re-encoding of the decoded output stream
• CPC Class Codes: H04N 19/436 using parallelised computational arrangements
• CPC Class Codes: H04N 19/44 Decoders specially adapted therefor, e.g. video decoders which are asymmetric with respect to the encoder
• CPC Class Codes: H04N 19/61 in combination with predictive coding
• CPC Class Codes: H04N 19/70 characterised by syntax aspects related to video coding, e.g. related to compression standards

Abstract

An image decoding apparatus (40) which decodes, in parallel, a coded stream (Str) having processing order dependency includes: a slice data predecoding unit (402) which predecodes, on a macroblock group basis, macroblock groups included in the coded stream (Str) to generate macroblock decoding information (1001) necessary for decoding other macroblock groups; and a first macroblock decoding unit (404) and a second macroblock decoding unit (405) each of which decodes a corresponding one of macroblock groups included in the coded stream (Str) in parallel. Each of the macroblock decoding units (404, 405), when decoding the corresponding one of macroblock groups, uses the macroblock decoding information (1001) that has been generated for the other macroblock group.

Claims

1. An image decoding apparatus which decodes a coded stream generated by coding, on a block-by-block basis, a picture including blocks, said image decoding apparatus comprising:

a predecoding unit configured to perform predecoding to generate block decoding information, on a block group basis, on a block group which contains blocks and which is included in the coded stream, the predecoding being part of the decoding, the block decoding information being a parameter necessary for decoding an other block group,

block decoding units each configured to perform the decoding on a block-by-block basis on one of block groups in parallel, the block groups being included in the coded stream and different from each other,

wherein, when the decoding is performed on the block group, each of said block decoding units is configured to perform the decoding on a corresponding one of the block groups by using the block decoding information generated in the predecoding performed on an other block group on which an other block decoding unit perform the decoding.

2. The image decoding apparatus according to claim 1,

wherein said predecoding unit is further configured to insert, at a beginning of each of the block groups in the coded stream, a bit pattern by which the beginning can be identified uniquely, and

each of said block decoding units is configured to search for the bit pattern inserted into the coded stream to find a block group on which the decoding is to be performed by said block decoding unit, and to decode the block group.

3. The image decoding apparatus according to claim 1,

wherein said predecoding unit is further configured to insert the generated block decoding information into the coded stream, and

each of said block decoding units is configured to obtain the coded stream into which the block decoding information is inserted, and to perform the decoding on the block group by using the block decoding information inserted into the coded stream.

4. The image decoding apparatus according to claim 1,

wherein said predecoding unit is configured to generate, as the block decoding information, a parameter necessary for the decoding of a block located at an end in the block group when generating the block decoding information, the parameter being obtained by performing the predecoding on the block group.

5. The image decoding apparatus according to claim 1,

wherein said predecoding unit, when generating the block decoding information, is configured to generate, as the block decoding information, a difference between a predetermined coefficient and a coefficient which is obtained by performing the predecoding on the block group and is necessary for the decoding of a block located at an end in the block group.

6. An image coding apparatus which codes, on a block-by-block basis, a picture including block groups that contains blocks, said image coding apparatus comprising:

block coding units each configured to code one of block groups on a block-by-block basis in parallel, the block groups being included in the picture and different from each other, and

an adjusting unit configured to match an intermediate stream with a coded stream generated by sequentially coding the block groups included in the picture in a predetermined processing order, by adjusting parameters used for coding and included in the intermediate stream generated by the coding performed by said block coding units.

7. The image coding apparatus according to claim 6,

wherein said adjusting unit is configured to determine the parameters used for the coding performed by said block coding units, and

each of said block coding units is configured to perform the coding using one of the parameters determined by said adjusting unit, so that the intermediate stream that matches with the coded stream is generated.

8. The image coding apparatus according to claim 6,

wherein, when coding the block groups, each of said block coding units is configured to include one of the parameters used for coding the block group, in the coded block group generated by coding the block groups, and to store at least a part of the parameter as a stored parameter, and

said adjusting unit is configured to match the intermediate stream with the coded stream, by modifying the parameters of the coded block groups, for each of the coded block groups included in the generated intermediate stream, by using the stored parameter which has been used for coding of the coded block group other than a current coded block group and which has been stored.

9. The image coding apparatus according to claim 8,

wherein each of the parameters included in the intermediate stream is coded, and

said adjusting unit is configured to perform again the coding that has been performed, on the parameter when modifying the parameter.

10. The image coding apparatus according to claim 8,

wherein, when coding the block group, each of said block coding units is configured to store, as the stored parameter, a parameter used for coding the block located at an end in the block group.

11. The image coding apparatus according to claim 8,

wherein, when modifying the parameter of the coded block group, said adjusting unit is configured to modify a parameter used for coding of a coded block located at a beginning from among coded blocks included in the coded block group.

12. The image coding apparatus according to claim 8,

wherein, when including the parameter used for coding the block group into the coded block group, each of said block coding units is configured to compress the parameter using a default coefficient that has been known before coding the block group, and to include the compressed parameter into the coded block group, and

said adjusting unit is configured to modify the compressed parameter of the coded block group by decompressing the compressed parameter of the coded block group with use of the default coefficient and compressing the decompressed parameter with use of the stored parameter.

13. The image coding apparatus according to claim 8,

wherein said adjusting unit is configured:

to determine whether or not a first skip parameter and a second skip parameter are both 0;

to modify, when a result of determination is not 0, the parameter by deleting the first skip parameter included in the intermediate stream as the parameter of the coded block group; and

to modify the second skip parameter included in the intermediate stream so that the modified second skip parameter means a number obtained by adding the number indicated by the second skip parameter to the number of the first skip parameter, the first skip parameter being included in the coded block group and indicating the number of consecutive blocks starting from a beginning of coded blocks included in the coded block group to the block of which coding is determined to be unnecessary, and the second skip parameter being included in the other coded block group and indicating the number of consecutive blocks starting from an end of coded blocks included in the other coded block group to the block of which coding is determined to be unnecessary.

14. An image decoding method for decoding a coded stream generated by coding, on a block-by-block basis, a picture including blocks, said image decoding method comprising:

predecoding to generate block decoding information, on a block group basis, on a block group which contains blocks and which is included in the coded stream, said predecoding being part of the decoding, the block decoding information being a parameter necessary for decoding an other block group,

decoding, on a block-by-block basis, on one of block groups in parallel, the block groups being included in the coded stream and different from each other,

wherein, in said decoding the block groups, said decoding is performed on a corresponding one of the block groups by using the block decoding information generated in said predecoding performed on an other block group.

15. An image coding method for coding, on a block-by-block basis, a picture including block groups that contains blocks, said image coding method comprising:

coding one of block groups on a block-by-block basis in parallel, the block groups being included in the picture and different from each other, and

matching an intermediate stream with a coded stream generated by sequentially coding the block groups included in the picture in a predetermined processing order, by adjusting parameters used for said coding and included in the intermediate stream generated by said coding.

16. A program for decoding a coded stream generated by coding, on a block-by-block basis, a picture including blocks, said program causing a computer to execute:

predecoding to generate block decoding information, on a block group basis, on a block group which contains blocks and which is included in the coded stream, the predecoding being part of the decoding, the block decoding information being a parameter necessary for decoding an other block group,

decoding, on a block-by-block basis, on one of block groups in parallel, the block groups being included in the coded stream and different from each other,

wherein, in the decoding the block groups, the decoding is performed on a corresponding one of the block groups by using the block decoding information generated in the predecoding performed on an other block group.

17. A program for coding, on a block-by-block basis, a picture including block groups that contains blocks, said program causing a computer to execute:

coding one of block groups on a block-by-block basis in parallel, the block groups being included in the picture and different from each other, and

matching an intermediate stream with a coded stream generated by sequentially coding the block groups included in the picture in a predetermined processing order, by adjusting parameters used for the coding and included in the intermediate stream generated by the coding.

18. An integrated circuit which decodes a coded stream generated by coding, on a block-by-block basis, a picture including blocks, said integrated circuit comprising:

a predecoding unit configured to perform predecoding to generate block decoding information, on a block group basis, on a block group which contains blocks and which is included in the coded stream, the predecoding being part of the decoding, the block decoding information being a parameter necessary for decoding an other block group,

block decoding units each configured to perform the decoding on a block-by-block basis on one of block groups in parallel, the block groups being included in the coded stream and different from each other,

wherein, when the decoding is performed on the block group, each of said block decoding units is configured to perform the decoding on a corresponding one of the block groups by using the block decoding information generated in the predecoding performed on an other block group on which an other block decoding unit perform the decoding.

19. An integrated circuit which codes, on a block-by-block basis, a picture including block groups that contains blocks, said integrated circuit comprising:

block coding units each configured to code one of block groups on a block-by-block basis in parallel, the block groups being included in the picture and different from each other, and

an adjusting unit configured to match an intermediate stream with a coded stream generated by sequentially coding the block groups included in the picture in a predetermined processing order, by adjusting parameters used for coding and included in the intermediate stream generated by the coding performed by said block coding units.