IMAGE CODING METHOD BASED ON CHROMA DEBLOCKING PARAMETER INFORMATION FOR MONOCHROME COLOR FORMAT IN VIDEO OR IMAGE CODING SYSTEM
According to a disclosure of the present document, information associated with a deblocking filter for performing deblocking filtering may include chroma component filter parameter information associated with deblocking parameter offsets that are applied to a chroma component. The chroma component filter parameter information may be selectively signaled on the basis of a chroma tool offset presence flag. Therefore, an effect of increasing overall coding efficiency may be derived by signaling chroma component filter parameter information only in the case of not a monochrome color format.
1 . An apparatus, comprising:
a memory; and
at least one processor connected to the memory, the at least one processor being configured to:
obtain image information from a bitstream, the image information including information related to a deblocking filter,
generate reconstructed samples for a current block, and
perform in-loop filtering on the reconstructed samples, the in-loop filtering including deblocking filtering based on the information related to the deblocking filter,
wherein a chroma tool offset present flag is included in a picture parameter set (PPS) of the bitstream,
wherein the chroma tool offset present flag equal to 1 indicates that chroma tool offset related information is present in the PPS, and the chroma tool offset present flag equal to 0 indicates that the chroma tool offset related information is not present in the PPS,
wherein the information related to the deblocking filter includes at least one of first chroma component filter parameter information, second chroma component filter parameter information, or third chroma component filter parameter information,
wherein the first chroma component filter parameter information indicates deblocking parameter offsets being applied to chroma components of slices referring to the PPS,
wherein the second chroma component filter parameter information indicates deblocking parameter offsets being applied to chroma components of slices in a current picture,
wherein the third chroma component filter parameter information indicates deblocking parameter offsets being applied to chroma components of a current slice,
wherein, based on the chroma tool offset present flag being equal to 1, the second chroma component filter parameter information is signaled from a picture header (PH) in the bitstream, and
wherein, based on the chroma tool offset present flag being equal to 0, the second chroma component filter parameter information is not signaled from the PH in the bitstream.
2 . The apparatus of claim 1 , wherein, based on the chroma tool offset present flag being equal to 1, the third chroma component filter parameter information is signaled from a slice header (SH) in the bitstream, and
wherein, based on the chroma tool offset present flag being equal to 0, the third chroma component filter parameter information is not signaled from the SH in the bitstream.
3 . The apparatus of claim 1 , wherein performing the in-loop filtering comprises deriving a chroma array type that is a variable related to a sampling format of a chroma component, and
wherein a value of the first chroma component filter parameter information is limited to 0 based on a case that a value of the chroma array type is 0.
4 . The apparatus of claim 1 , wherein performing the in-loop filtering comprises deriving a chroma array type that is a variable related to a sampling format of a chroma component, and
wherein a value of the second chroma component filter parameter information is limited to 0 based on a case that a value of the chroma array type is 0.
5 . The apparatus of claim 1 , wherein performing the in-loop filtering comprises deriving a chroma array type that is a variable related to a sampling format of a chroma component, and
wherein the second chroma component filter parameter information is included in the PH based on a case that a value of the chroma array type is not 0.
6 . The apparatus of claim 1 , wherein performing the in-loop filtering comprises deriving a chroma array type that is a variable related to a sampling format of a chroma component, and
wherein a value of the third chroma component filter parameter information is limited to 0 based on a case that a value of the chroma array type is 0.
7 . The apparatus of claim 1 , wherein performing the in-loop filtering comprises deriving a chroma array type that is a variable related to a sampling format of a chroma component, and
wherein the third chroma component filter parameter information is included in a slice header (SH) based on a case that a value of the chroma array type is not 0.
8 . The apparatus of claim 1 , wherein the information related to the deblocking filter further comprises a chroma deblocking parameter present flag and a chroma deblocking filter override enabled flag,
wherein the chroma deblocking parameter present flag is related to whether chroma deblocking related information is present in the PPS, and the chroma deblocking parameter present flag is included in the PPS,
wherein the chroma deblocking filter override enabled flag is related to whether the chroma deblocking related information is present in the PH or a slice header (SH), and
wherein the chroma deblocking filter override enabled flag is included in the PPS based on a case that a value of the chroma deblocking parameter present flag is 1.
9 . The apparatus of claim 8 , wherein the information related to the deblocking filter further comprises a deblocking filter override enabled flag,
wherein the deblocking filter override enabled flag is related to whether a deblocking operation for pictures referring to the PPS is redefined at a picture level or a slice level, and
wherein the chroma deblocking filter override enabled flag is included in the PPS based on a case that a value of the deblocking filter override enabled flag is 1.
10 . The apparatus of claim 9 , wherein the second chroma component filter parameter information is included in the PH based on a case that a value of the chroma deblocking parameter present flag is 1 and a value of the chroma deblocking filter override enabled flag is 1.
11 . The apparatus of claim 8 , wherein the third chroma component filter parameter information is included in the SH based on a case that a value of the chroma deblocking parameter present flag is 1 and a value of the chroma deblocking filter override enabled flag is 1.
12 . The apparatus of claim 8 , wherein performing the in-loop filtering comprises deriving a chroma array type that is a variable related to a sampling format of a chroma component,
wherein a value of the chroma deblocking parameter present flag is limited to 0 based on a case that a value of the chroma array type is 0, and
wherein a value of the chroma deblocking filter override enabled flag is limited to 0 based on a case that the value of the chroma array type is 0.
13 . An apparatus, comprising:
a memory; and
at least one processor connected to the memory, the at least one processor being configured to:
generate reconstructed samples for a current block,
apply an in-loop filter including a deblocking filter to the reconstructed samples,
generate information related to the deblocking filter, and
encode image information including the information related to the deblocking filter,
wherein a chroma tool offset present flag is encoded into a picture parameter set (PPS) in a bitstream,
wherein the chroma tool offset present flag equal to 1 indicates that chroma tool offset related information is present in the PPS, and the chroma tool offset present flag equal to 0 indicates that the chroma tool offset related information is not present in the PPS,
wherein the information related to the deblocking filter includes at least one of first chroma component filter parameter information, second chroma component filter parameter information, or third chroma component filter parameter information,
wherein the first chroma component filter parameter information indicates deblocking parameter offsets being applied to chroma components of slices referring to the PPS,
wherein the second chroma component filter parameter information indicates deblocking parameter offsets being applied to chroma components of slices in a current picture,
wherein the third chroma component filter parameter information indicates deblocking parameter offsets being applied to chroma components of a current slice,
wherein, based on the chroma tool offset present flag being equal to 1, the second chroma component filter parameter information is encoded into a picture header (PH) in the bitstream, and
wherein, based on the chroma tool offset present flag being equal to 0, the second chroma component filter parameter information is not encoded into the PH in the bitstream.
14 . An apparatus, comprising:
at least one processor configured to obtain a bitstream of the image information, wherein the bitstream is generated by generating reconstructed samples for a current block, applying an in-loop filter including a deblocking filter to the reconstructed samples, generating information related to the deblocking filter, and encoding the image information including the information related to the deblocking filter; and
a transmitter configured to transmit the data including the bitstream of the image information,
wherein a chroma tool offset present flag is encoded into a picture parameter set (PPS) in the bitstream,
wherein the chroma tool offset present flag equal to 1 indicates that chroma tool offset related information is present in the PPS, and the chroma tool offset present flag equal to 0 indicates that the chroma tool offset related information is not present in the PPS,
wherein the information related to the deblocking filter includes at least one of first chroma component filter parameter information, second chroma component filter parameter information, or third chroma component filter parameter information,
wherein the first chroma component filter parameter information indicates deblocking parameter offsets being applied to chroma components of slices referring to the PPS,
wherein the second chroma component filter parameter information indicates deblocking parameter offsets being applied to chroma components of slices in a current picture,
wherein the third chroma component filter parameter information indicates deblocking parameter offsets being applied to chroma components of a current slice,
wherein, based on the chroma tool offset present flag being equal to 1, the second chroma component filter parameter information is encoded into a picture header (PH) in the bitstream, and
wherein, based on the chroma tool offset present flag being equal to 0, the second chroma component filter parameter information is not encoded into the PH in the bitstream.