Moving image decoding apparatus, moving image coding apparatus, moving image decoding circuit, and moving image decoding method

1. A moving image decoding apparatus which performs motion-compensation decoding involving motion compensation of a stream of motion-compensation coded moving images, said moving image decoding apparatus comprising:

a decoding unit configured to decode, from the stream, a plurality of motion compensation filter coefficients (filter coefficients of a motion compensation filter) for use in the motion-compensation decoding;

a memory for holding the motion compensation filter coefficients included in the stream decoded by said decoding unit;

a filter coefficient storage unit for holding at least one of the motion compensation filter coefficients held in said memory, the at least one motion compensation filter coefficient being required for the motion compensation;

a motion compensation unit configured to perform the motion compensation using the at least one motion compensation filter coefficient held in said filter coefficient storage unit; and

a transfer control unit configured to write, to said memory, the motion compensation filter coefficients decoded by said decoding unit, and transfer the at least one motion compensation filter coefficient from said memory to said filter coefficient storage unit.

2. The moving image decoding apparatus according to claim 1 ,

wherein said transfer control unit is configured to transfer the at least one motion compensation filter coefficient from said memory to said filter coefficient storage unit, only when said filter coefficient storage unit does not hold the at least one motion compensation filter coefficient.

3. The moving image decoding apparatus according to claim 2 ,

wherein said decoding unit is configured to decode, from the stream, a plurality of motion compensation filter coefficients for use in the motion-compensation decoding and identification information identifying the at least one motion compensation filter coefficient,

said moving image decoding apparatus further comprises:

a storage state management unit configured to manage information indicating whether or not said filter coefficient storage unit holds the at least one motion compensation filter coefficient identified based on the identification information; and

said transfer control unit is configured to transfer the at least one motion compensation filter coefficient from said memory to said filter coefficient storage unit, based on the information managed by said storage state management unit.

4. The moving image decoding apparatus according to claim 3 ,

wherein said transfer control unit is configured to transfer the at least one motion compensation filter coefficient identified based on said identification information from said memory to an area which is of said filter coefficient storage unit and holds a motion compensation filter coefficient transferred from said memory at earliest time, only when it is found out, with reference to the information managed by said storage state management unit, that said filter coefficient storage unit does not hold the at least one motion compensation filter coefficient.

5. The moving image decoding apparatus according to claim 3 ,

wherein said transfer control unit is configured to transfer the at least one motion compensation filter coefficient identified based on said identification information from said memory to an area which is of said filter coefficient storage unit and holds a motion compensation filter coefficient transferred from said memory most recently, only when it is found out, with reference to the information managed by said storage state management unit, that said filter coefficient storage unit does not hold the at least one motion compensation filter coefficient.

6. The moving image decoding apparatus according to claim 3 ,

Wherein, only when it is found out, with reference to the information managed by said storage state management unit, that said filter coefficient storage unit does not hold the at least one motion compensation filter coefficient, said transfer control unit is configured to arbitrarily select an area which is of said filter coefficient storage unit and holds a motion compensation filter coefficient, and transfer the at least one motion compensation filter coefficient identified based on said identification information from said memory to the selected area.

7. The moving image decoding apparatus according to claim 3 , further comprising

a reference management unit configured to manage use history information indicating the number of times of reference from a start of the decoding for each of the plurality of motion compensation filter coefficients included in the stream,

wherein said transfer control unit is configured to transfer the at least one motion compensation filter coefficient from said memory to said filter coefficient storage unit, based on the information managed by said storage state management unit and the information managed by said reference management unit.

8. The moving image decoding apparatus according to claim 7 ,

wherein said transfer control unit is configured to transfer the at least one motion compensation filter coefficient identified based on said identification information from said memory to an area which is determined, with reference to the information managed by said reference management unit, to be of said filter coefficient storage unit and holds a motion compensation filter coefficient least frequently referred to, only when it is found out, with reference to the information managed by said storage state management unit, that said filter coefficient storage unit does not hold the at least one motion compensation filter coefficient.

9. The moving image decoding apparatus according to claim 7 ,

wherein said transfer control unit is configured to transfer the at least one motion compensation filter coefficient identified based on said identification information from said memory to an area which is determined, with reference to the information managed by said reference management unit, to be of said filter coefficient storage unit and holds a motion compensation filter coefficient least frequently used in a predetermined period from a past time to a current time, only when it is found out, with reference to the information managed by said storage state management unit, that said filter coefficient storage unit does not hold the at least one motion compensation filter coefficient.

10. The moving image decoding apparatus according to claim 7 ,

wherein said transfer control unit is configured to transfer the at least one motion compensation filter coefficient identified based on said identification information from said memory to an area which is determined, with reference to the information managed by said reference management unit, to be of said filter coefficient storage unit and holds a motion compensation filter coefficient most frequently used in a predetermined period from a past time to a current time, only when it is found out, with reference to the information managed by said storage state management unit, that said filter coefficient storage unit does not hold the at least one motion compensation filter coefficient.

11. The moving image decoding apparatus according to claim 7 ,

wherein said transfer control unit is configured to transfer the at least one motion compensation filter coefficient identified based on said identification information from said memory to an area which is determined, with reference to the information managed by said reference management unit, to be of said filter coefficient storage unit and holds a motion compensation filter coefficient most frequently referred to, only when it is found out, with reference to the information managed by said storage state management unit, that said filter coefficient storage unit does not hold the at least one motion compensation filter coefficient.

12. The moving image decoding apparatus according to claim 2 ,

wherein said decoding unit is configured to decode, from the stream, the plurality of motion compensation filter coefficients for use in the motion-compensation decoding and the identification information identifying the at least one motion compensation filter coefficient,

said moving image decoding apparatus further comprises:

a pre-decoding unit configured to decode, from the stream, the at least one motion compensation filter coefficient among the plurality of motion compensation filter coefficients included in the stream, prior to the decoding by said decoding unit;

a storage state management unit configured to manage information indicating whether or not said filter coefficient storage unit holds the at least one motion compensation filter coefficient identified based on the identification information; and

a statistical information management unit configured to manage a use state of each of the motion compensation filter coefficients decoded by said pre-decoding unit and to be decoded by said decoding unit, and

said transfer control unit is configured to transfer the at least one motion compensation filter coefficients from said memory to said filter coefficient storage unit, based on the information managed by said storage state management unit and the use state managed by said statistical information management unit.

13. The moving image decoding apparatus according to claim 12 ,

wherein said transfer control unit is configured to transfer the at least one motion compensation filter coefficient identified based on said identification information from said memory to an area which is determined, with reference to the use state managed by said statistical information management unit, to be of said filter coefficient storage unit and holds a motion compensation filter coefficient to be referred to least frequently, only when it is found out, with reference to the information managed by said storage state management unit, that said filter coefficient storage unit does not hold the at least one motion compensation filter coefficient.

14. The moving image decoding apparatus according to claim 12 ,

wherein said transfer control unit is configured to transfer the at least one motion compensation filter coefficient identified based on said identification information from said memory to an area which is determined, with reference to the use state managed by said statistical information management unit, to be of said filter coefficient storage unit and holds a motion compensation filter coefficient to be referred to least frequently in a predetermined period, only when it is found out, with reference to the information managed by said storage state management unit, that said filter coefficient storage unit does not hold the at least one motion compensation filter coefficient.

15. The moving image decoding apparatus according to claim 2 , further comprising:

a reversible coding unit configured to reversibly code the plurality of motion compensation filter coefficients included in the stream; and

a reversible decoding unit configured to reversibly decode the at least one motion compensation filter coefficient among the plurality of motion compensation filter coefficients reversibly coded by said reversible coding unit, and write, under control of said transfer control unit, the reversibly decoded at least one motion compensation filter coefficient into said filter coefficient storage unit.

16. A moving image coding apparatus which performs motion-compensation coding using a current image to be coded and a reference image, said moving image coding apparatus comprising:

a generation unit configured to generate a plurality of motion compensation filter coefficients for use in the motion-compensation coding;

a memory for holding the motion compensation filter coefficients generated by said generation unit;

a filter coefficient storage unit for holding at least one of the motion compensation filter coefficients held in said memory, the at least one motion compensation filter coefficient being required for the motion compensation;

a motion estimation unit configured to generate a prediction image by performing motion compensation between the current image to be coded and the reference image, using the at least one motion compensation filter coefficient held in said filter coefficient storage unit; and

a transfer unit configured to write, to said memory, the motion compensation filter coefficients generated by said generation unit, and transfer the at least one motion compensation filter coefficient from said memory to said filter coefficient storage unit, only when said filter coefficient storage unit does not hold the at least one motion compensation filter coefficient.

17. The moving image coding apparatus according to claim 16 ,

wherein said motion estimation unit is configured to generate identification information identifying the at least one motion compensation filter coefficient for use in the motion compensation;

said moving image coding apparatus further comprises

a storage state management unit configured to manage information indicating whether or not said filter coefficient storage unit holds the at least one motion compensation filter coefficient identified based on the identification information, and

said transfer control unit is configured to transfer the at least one motion compensation filter coefficient from said memory to said filter coefficient storage unit, based on the information managed by said storage state management unit.

18. The moving image coding apparatus according to claim 16 ,

wherein said motion estimation unit is configured to generate identification information identifying the at least one motion compensation filter coefficient for use in the motion compensation,

said moving image coding apparatus further comprises:

a reference management unit configured to manage use history information indicating the number of times of reference from a start of the motion compensation for each of the at least one motion compensation filter coefficient for use in the motion compensation; and

a storage state management unit configured to manage information indicating whether or not said filter coefficient storage unit holds the at least one motion compensation filter coefficient identified based on the identification information, and

said transfer control unit is configured to transfer the at least one motion compensation filter coefficient from said memory to said filter coefficient storage unit, based on the use history information managed by said reference management unit and the information managed by said storage state management unit.

19. The moving image coding apparatus according to claim 16 , further comprising:

a reversible coding unit configured to reversibly code the plurality of motion compensation filter coefficients; and

a reversible decoding unit configured to reversibly decode the at least one motion compensation filter coefficient among the plurality of motion compensation filter coefficients reversibly coded by said reversible coding unit, and write, under control of said transfer control unit, the reversibly decoded at least one motion compensation filter coefficient into said filter coefficient storage unit,

wherein said transfer control unit is configured to write, to said memory, the reversibly coded motion compensation filter coefficients, read out the at least one motion compensation filter coefficient from said memory, and transfer the read-out at least one motion compensation filter coefficient to said reversible decoding unit.

20. An integrated circuit which performs motion-compensation decoding involving motion compensation of a stream of motion-compensation coded moving images, said integrated circuit comprising:

a decoding unit configured to decode, from the stream, a plurality of motion compensation filter coefficients (filter coefficients of a motion compensation filter) for use in the motion-compensation decoding;

a memory for holding the motion compensation filter coefficients included in the stream decoded by said decoding unit;

a filter coefficient storage unit for holding at least one of the motion compensation filter coefficients held in said memory, the at least one motion compensation filter coefficient being required for the motion compensation;

a motion compensation unit configured to perform the motion compensation using the at least one motion compensation filter coefficient held in said filter coefficient storage unit; and

a transfer control unit configured to write, to said memory, the motion compensation filter coefficients decoded by said decoding unit, transfer the at least one motion compensation filter coefficient from said memory to said filter coefficient storage unit, only when said filter coefficient storage unit does not hold the at least one motion compensation filter coefficient.

21. A moving image decoding method of performing motion-compensation decoding involving motion compensation of a stream of motion-compensation coded moving images, said moving image decoding method comprising:

decoding, from the stream, a plurality of motion compensation filter coefficients (filter coefficients of a motion compensation filter) for use in the motion-compensation decoding;

holding the motion compensation filter coefficients included in the stream decoded in said decoding;

holding at least one of the motion compensation filter coefficients in a filter coefficient storage unit, the at least one motion compensation filter coefficient being required for the motion compensation;

performing the motion compensation using the at least one motion compensation filter coefficient held in the filter coefficient storage unit; and

writing, to the memory, the motion compensation filter coefficients decoded in said decoding, transferring the at least one motion compensation filter coefficient, only when the filter coefficient storage unit does not hold the at least one motion compensation filter coefficient for use in the motion compensation.

22. A moving image decoding apparatus which decodes, from a stream, a plurality of motion compensation filter coefficients for use in motion-compensation decoding, said moving image decoding apparatus comprising:

a pre-decoding unit configured to decode, from the stream, the plurality of motion compensation filter coefficients, prior to decoding by a decoding unit;

a memory for holding the motion compensation filter coefficients decoded by said decoding unit;

a filter coefficient storage unit for holding at least one of the motion compensation filter coefficients held in said memory, the at least one motion compensation filter coefficient being required for the motion compensation; and

a control unit configured to cause said filter coefficient storage unit to hold the at least one motion compensation filter coefficient, based on the motion compensation filter coefficients decoded by said decoding unit.