Moving-picture encoding apparatus and moving-picture decoding apparatus

1. A moving-picture decoding system, comprising:

circuitry configured to:

obtain transformation coefficients from coded data obtained by coding processes according to prediction directions;

rearrange the transformation coefficients according to a scanning order corresponding to a prediction direction of a target block from among scanning orders predetermined for prediction directions;

classify a mode applied to the target block into a predetermined first mode or a predetermined second mode;

obtain a predictive residual signal by subjecting the rearranged transformation coefficients to an inverse orthogonal transformation by use of a first transformation basis common to the prediction directions if the applied mode is classified into the first mode, and obtain a predictive residual signal by subjecting the rearranged transformation coefficients to an inverse orthogonal transformation by use of a second transformation basis different from the first transformation basis if the applied mode is classified into the second mode; and

generate a decoded image signal by use of the predictive residual signal,

wherein the first transformation basis is used for both of a vertical inverse orthogonal transformation and a horizontal inverse orthogonal transformation, and the second transformation basis is used for both of the vertical inverse orthogonal transformation and the horizontal inverse orthogonal transformation.

2. The moving-picture decoding system of claim 1 , wherein the first transformation basis is used for unidirectional intra-prediction modes comprising a plurality of unidirectional intra-prediction modes other than a vertical mode or a horizontal mode, and wherein the scanning orders comprises a plurality of scanning orders for the plurality of unidirectional intra-prediction modes.

3. The moving-picture decoding system of claim 2 , wherein the plurality of modes comprises a first mode corresponding to a diagonal down right direction, a second mode corresponding to a vertical right direction, and a third mode corresponding to a horizontal down direction.

4. The moving-picture decoding system of claim 2 , wherein the circuitry comprises a storage memory configured to store the coded data, and wherein the circuitry is configured to obtain the transformation coefficients from the coded data stored in the storage memory.

5. The moving-picture decoding system of claim 2 , wherein the circuitry comprises a buffer memory configured to buffer the coded data, and wherein the circuitry is configured to obtain the transformation coefficients from the coded data in the buffer memory.

6. The moving-picture decoding system of claim 2 , wherein the circuitry comprises a receiver configured to receive the coded data from an external apparatus through a transmission system, and wherein the circuitry is configured to obtain the transformation coefficients from the coded data received by the receiver.

7. The moving-picture decoding system of claim 2 , wherein the circuitry comprises at least one dedicated hardware processor configured to:

obtain the transformation coefficients from the coded data obtained by the coding processes according to the intra-prediction modes;

rearrange the transformation coefficients according to the scanning order corresponding to the prediction direction of the target block from among the scanning orders predetermined for the prediction directions;

classify the mode applied to the target block into the predetermined first mode or the predetermined second mode;

obtain the predictive residual signal by subjecting the rearranged transformation coefficients to the inverse orthogonal transformation by use of the first transformation basis common to the prediction directions if the applied mode is classified into the first mode, and obtain the predictive residual signal by subjecting the rearranged transformation coefficients to the inverse orthogonal transformation by use of the second transformation basis different from the first transformation basis if the applied mode is classified into the second mode; and

generate the decoded image signal by use of the predictive residual signal.

8. The moving-picture decoding system of claim 2 , wherein the circuitry comprises:

a memory that stores a program; and

at least one general purpose processor coupled to the memory and configured to execute the program,

wherein the program is configured to, when executed by the at least one general purpose processor, cause the at least one general purpose processor to:

obtain the transformation coefficients from the coded data obtained by the coding processes according to the intra-prediction modes;

rearrange the transformation coefficients according to the scanning order corresponding to the prediction direction of the target block from among the scanning orders predetermined for the prediction directions;

classify the mode applied to the target block into the predetermined first mode or the predetermined second mode;

obtain the predictive residual signal by subjecting the rearranged transformation coefficients to the inverse orthogonal transformation by use of the first transformation basis common to the prediction directions if the applied mode is classified into the first mode, and obtain the predictive residual signal by subjecting the rearranged transformation coefficients to the inverse orthogonal transformation by use of the second transformation basis different from the first transformation basis if the applied mode is classified into the second mode; and

generate the decoded image signal by use of the predictive residual signal.

9. The moving-picture decoding system of claim 2 , wherein the at least one general purpose processor comprises a CPU configured to execute the program, and wherein the program is configured to, when executed by the CPU, cause the CPU to:

obtain the transformation coefficients from the coded data obtained by the coding processes according to the intra-prediction modes;

rearrange the transformation coefficients according to the scanning order corresponding to the prediction direction of the target block from among the scanning orders predetermined for the prediction directions;

classify the mode applied to the target block into the predetermined first mode or the predetermined second mode;

obtain the predictive residual signal by subjecting the rearranged transformation coefficients to the inverse orthogonal transformation by use of the first transformation basis common to the prediction directions if the applied mode is classified into the first mode, and obtain the predictive residual signal by subjecting the rearranged transformation coefficients to the inverse orthogonal transformation by use of the second transformation basis different from the first transformation basis if the applied mode is classified into the second mode; and

generate the decoded image signal by use of the predictive residual signal.

10. A moving-picture decoding method which uses circuitry, comprising:

obtaining transformation coefficients from coded data obtained by coding processes according to prediction directions;

rearranging the transformation coefficients according to a scanning order corresponding to a prediction direction of a target block from among scanning orders predetermined for prediction directions;

classifying a mode applied to the target block into a predetermined first mode or a predetermined second mode;

obtaining a predictive residual signal by subjecting the rearranged transformation coefficients to an inverse orthogonal transformation by use of a first transformation basis common to the prediction directions if the applied mode is classified into the first mode, and obtaining a predictive residual signal by subjecting the rearranged transformation coefficients to an inverse orthogonal transformation by use of a second transformation basis different from the first transformation basis if the applied mode is classified into the second mode; and

generating a decoded image signal by use of the predictive residual signal,

wherein the first transformation basis is used for both of a vertical inverse orthogonal transformation and a horizontal inverse orthogonal transformation, and the second transformation basis is used for both of the vertical inverse orthogonal transformation and the horizontal inverse orthogonal transformation.

11. The moving-picture decoding method of claim 10 , wherein the first transformation basis is used for unidirectional intra-prediction modes comprising a plurality of unidirectional intra-prediction modes other than a vertical mode or a horizontal mode, and wherein the scanning orders comprises a plurality of scanning orders for the plurality of unidirectional intra-prediction modes.

12. The moving-picture decoding method of claim 11 , wherein the plurality of modes comprises a first mode corresponding to a diagonal down right direction, a second mode corresponding to a vertical right direction, and a third mode corresponding to a horizontal down direction.

13. The moving-picture decoding method of claim 11 , wherein the circuitry comprises a storage memory configured to store the coded data, and wherein the circuitry is configured to obtain the transformation coefficients from the coded data stored in the storage memory.

14. The moving-picture decoding method of claim 11 , wherein the circuitry comprises a buffer memory configured to buffer the coded data, and wherein the circuitry is configured to obtain the transformation coefficients from the coded data in the buffer memory.

15. The moving-picture decoding method of claim 11 , wherein the circuitry comprises a receiver configured to receive the coded data from an external apparatus through a transmission system, and wherein the circuitry is configured to obtain the transformation coefficients from the coded data received by the receiver.

16. A moving-picture encoding system, comprising:

circuitry configured to:

obtain a predictive residual signal by using coding processes according to prediction directions;

classify a mode applied to a target block into a predetermined first mode or a predetermined second mode;

obtain transformation coefficients by subjecting the predictive residual signal to an orthogonal transformation by use of a first transformation basis common to the prediction directions if the applied mode is classified into the first mode, and obtain transformation coefficients by subjecting the predictive residual signal to an orthogonal transformation by use of a second transformation basis different from the first transformation basis if the applied mode is classified into the second mode; and

rearrange the transformation coefficients according to a scanning order corresponding to a prediction direction of the target block from among scanning orders predetermined for the prediction directions; and

encode the rearranged transformation coefficient to generate coded data,

wherein the first transformation basis is used for both of a vertical orthogonal transformation and a horizontal orthogonal transformation, and the second transformation basis is used for both of the vertical orthogonal transformation and the horizontal orthogonal transformation.

17. The moving-picture encoding system of claim 16 , wherein the first transformation basis is used for unidirectional intra-prediction modes comprising a plurality of unidirectional intra-prediction modes other than a vertical mode or a horizontal mode, and wherein the scanning orders comprises a plurality of scanning orders for the plurality of unidirectional intra-prediction modes.

18. The moving-picture encoding system of claim 17 , wherein the plurality of unidirectional intra-prediction modes comprises a first mode corresponding to a diagonal down right direction, a second mode corresponding to a vertical right direction, and a third mode corresponding to a horizontal down direction.

19. The moving-picture encoding system of claim 17 , wherein the circuitry comprises a storage memory configured to store the coded data.

20. The moving-picture encoding system of claim 17 , wherein the circuitry comprises a transmitter configured to transmit the coded data to an external apparatus through a transmission system.

21. The moving-picture encoding system of claim 17 , wherein the circuitry comprises at least one dedicated hardware processor configured to:

obtain the predictive residual signal by using the coding processes according to the prediction directions;

classify the mode applied to the target block into the predetermined first mode or the predetermined second mode;

obtain the transformation coefficients by subjecting the predictive residual signal to the orthogonal transformation by use of the first transformation basis common to the prediction directions if the applied mode is classified into the first mode, and obtain the transformation coefficients by subjecting the predictive residual signal to the orthogonal transformation by use of the second transformation basis different from the first transformation basis if the applied mode is classified into the second mode; and

rearrange the transformation coefficients according to the scanning order corresponding to the prediction direction of the target block from among the scanning orders predetermined for the prediction directions; and

encode the rearranged transformation coefficient to generate the coded data.

22. The moving-picture encoding system of claim 17 , wherein the circuitry comprises:

a memory that stores a program; and

at least one general purpose processor coupled to the memory and configured to execute the program,

wherein the program is configured to, when executed by the at least one general purpose processor, cause the at least one general purpose processor to:

obtain the predictive residual signal by using the coding processes according to the prediction directions;

classify the mode applied to the target block into the predetermined first mode or the predetermined second mode;

obtain the transformation coefficients by subjecting the predictive residual signal to the orthogonal transformation by use of the first transformation basis common to the prediction directions if the applied mode is classified into the first mode, and obtain the transformation coefficients by subjecting the predictive residual signal to the orthogonal transformation by use of the second transformation basis different from the first transformation basis if the applied mode is classified into the second mode; and

rearrange the transformation coefficients according to the scanning order corresponding to the prediction direction of the target block from among the scanning orders predetermined for the prediction directions; and

encode the rearranged transformation coefficient to generate the coded data.

23. A moving-picture encoding method, performed by circuitry, comprising:

obtaining a predictive residual signal by using coding processes according to prediction directions;

classifying a mode applied to a target block into a predetermined first mode or a predetermined second mode;

obtaining transformation coefficients by subjecting the predictive residual signal to an orthogonal transformation by use of a first transformation basis common to the prediction directions if the applied mode is classified into the first mode, and obtaining transformation coefficients by subjecting the predictive residual signal to an orthogonal transformation by use of a second transformation basis different from the first transformation basis if the applied mode is classified into the second mode; and

rearranging the transformation coefficients according to a scanning order corresponding to a prediction direction of the target block from among scanning orders predetermined for the prediction directions; and

encoding the rearranged transformation coefficient to generate coded data,

wherein the first transformation basis is used for both of a vertical orthogonal transformation and a horizontal orthogonal transformation, and the second transformation basis is used for both of the vertical orthogonal transformation and the horizontal orthogonal transformation.

24. The moving-picture encoding method of claim 23 , wherein the first transformation basis is used for unidirectional intra-prediction modes comprising a plurality of unidirectional intra-prediction modes other than a vertical mode or a horizontal mode, and wherein the scanning orders comprises a plurality of scanning orders for the plurality of unidirectional intra-prediction modes.

25. The moving-picture encoding method of claim 24 , wherein the plurality of unidirectional intra-prediction modes comprises a first mode corresponding to a diagonal down right direction, a second mode corresponding to a vertical right direction, and a third mode corresponding to a horizontal down direction.

26. The moving-picture encoding method of claim 24 , wherein the circuitry comprises a storage memory configured to store the coded data.

27. The moving-picture encoding method of claim 24 , wherein the circuitry comprises a transmitter configured to transmit the coded data to an external apparatus through a transmission system.