Encoder, a decoder and corresponding methods for intra prediction
Devices and methods for Intra prediction are provided. The method includes: obtaining a value of an indication information of a current block. When the value of the indication information indicates the intra prediction mode of the current block is not comprised in the set of most probable modes, deriving the intra prediction mode IntraPredModeY of the current block by the following ordered steps: i. IntraPredModeY is set equal to intra_luma_mpm_remainder[xCb][yCb], ii. The value of IntraPredModeY is incremented by one. The method can improve the efficiency to determine the intra prediction mode of the current block.
1 . A device for intra prediction, comprising:
a receiver, configured to receive a bitstream; and
at least one storage medium configured to store the bitstream;
wherein the bitstream comprises:
indication information of a current block, a value of the indication information indicating whether an intra prediction mode of the current block is included in a set of most probable modes, wherein the set of most probable modes comprises a planar mode and five candidate intra prediction modes; and
a syntax element representing a remainder intra prediction mode when the value of the indication information indicates the intra prediction mode of the current block is not included in the set of most probable modes.
2 . The device of claim 1 , wherein a value of the planar mode is 0, and candModeList[i] represents a candidate intra prediction mode included in the set of most probable modes other than the planar mode, i is an integer from 0 to 4.
3 . The device of claim 1 , wherein the value of the indication information is indicated by a flag, and when a value of the flag is not equal to 1, the intra prediction mode of the current block is not included in the set of most probable modes.
4 . The device of claim 1 , wherein the syntax element representing the remainder intra prediction mode is truncated binary coded.
5 . The device of claim 2 , wherein the syntax element representing the remainder intra prediction mode is intra_luma_mpm_remainder.
6 . The device of claim 5 , wherein to derive the intra_luma_mpm_remainder:
the intra_luma_mpm_remainder is set equal to the intra prediction mode of the current block;
a value of the intra_luma_mpm_remainder is reduced by one; and
for i equal to 0 to 4, inclusive, when the intra prediction mode of the current block is greater than or equal to candModeList[i], the value of the intra_luma_mpm_remainder is reduced by one.
7 . The device of claim 1 , wherein the bitstream further comprises a planar flag indicating whether the intra prediction mode of the current block is the planar mode.
8 . The device of claim 7 , wherein the planar flag is context adaptive binary arithmetic coding (CABAC) coded.
9 . The device of claim 8 , wherein the CABAC indicates whether the current block is an intra block with intra sub-partition (ISP) coding mode enabled, or whether the current block is an intra block with multiple reference line (MRL) enabled.
10 . A method for intra prediction, comprising:
receiving a bitstream; and
storing the bitstream;
wherein the bitstream comprises:
indication information of a current block, a value of the indication information indicating whether an intra prediction mode of the current block is included in a set of most probable modes, wherein the set of most probable modes comprises a planar mode and five candidate intra prediction modes; and
a syntax element representing a remainder intra prediction mode when the value of the indication information indicates the intra prediction mode of the current block is not included in the set of most probable modes.
11 . The method of claim 10 , wherein a value of the planar mode is 0, and candModeList[i] represents a candidate intra prediction mode included in the set of most probable modes other than the planar mode, i is an integer from 0 to 4.
12 . The method of claim 10 , wherein the value of the indication information is indicated by a flag, and wherein when a value of the flag is not equal to 1, the intra prediction mode of the current block is not included in the set of most probable modes.
13 . The method of claim 10 , wherein the syntax element representing the remainder intra prediction mode is truncated binary coded.
14 . The method of claim 11 , wherein the syntax element representing the remainder intra prediction mode is intra_luma_mpm_remainder.
15 . The method of claim 14 , wherein the intra_luma_mpm_remainder is derived by:
setting the intra_luma_mpm_remainder equal to the intra prediction mode of the current block;
reducing a value of the intra_luma_mpm_remainder by one; and
for i equal to 0 to 4, inclusive, when the intra prediction mode of the current block is greater than or equal to candModeList[i], reducing the value of the intra_luma_mpm_remainder by one.
16 . The method of claim 10 , wherein the bitstream further comprises a planar flag indicating whether the intra prediction mode of the current block is the planar mode.
17 . The method of claim 16 , wherein the planar flag is context adaptive binary arithmetic coding (CABAC) coded.
18 . The method of claim 17 , wherein the CABAC indicates whether the current block is an intra block with intra sub-partition (ISP) coding mode enabled, or whether the current block is an intra block with multiple reference line (MRL) enabled.
19 . An encoding device, comprising:
a memory configured to store instructions; and
a processor coupled to the memory and configured to execute the instructions to cause the encoding device to:
determine whether an intra prediction mode of a current block is included in a set of most probable modes, wherein the set of most probable modes comprises a planar mode and five candidate intra prediction modes; and
encode a syntax element representing a remainder intra prediction mode when a value of indication information indicates the intra prediction mode of the current block is not included in the set of most probable modes.
20 . The encoding device of claim 19 , wherein the syntax element representing the remainder intra prediction mode is intra_luma_mpm_remainder, and to derive the intra_luma_mpm_remainder:
the intra_luma_mpm_remainder is set equal to the intra prediction mode of the current block;
a value of the intra_luma_mpm_remainder is reduced by one; and
for i equal to 0 to 4, inclusive, when the intra prediction mode of the current block is greater than or equal to candModeList[i], the value of the intra_luma_mpm_remainder is reduced by one.