Method and apparatus for processing image service
A method, performed by a digital device, for processing an image service according to the present document comprises the steps of: receiving image information; decoding a first image on the basis of the image information; processing the decoded first image to be displayed on a first area of a display screen; and processing a second image to be displayed on a second area of the display screen.
1. An image decoding method performed by a decoding apparatus, the method comprising:
deriving a first intra prediction mode based on a first neighboring block which is located in a left side of a current block;
deriving a second intra prediction mode based on a second neighboring block which is located in an upper side of the current block;
configuring an Most Probable Mode (MPM) list for the current block based on the first intra prediction mode and the second intra prediction mode;
deriving an intra prediction mode of the current block based on the MPM list;
generating prediction samples for the current block based on the intra prediction mode; and
generating a reconstructed picture for the current block based on the prediction samples,
wherein the MPM list comprises MPM candidates derived based on whether at least one of the first intra prediction mode or the second intra prediction mode is non-directional intra prediction mode,
wherein the MPM candidates which are derived based on a case that the first intra prediction mode and the second intra prediction mode are both the non-directional intra prediction mode, comprise:
a DC intra prediction mode, a vertical directional intra prediction mode, a horizontal directional intra prediction mode, an intra prediction mode of which mode number is equal to a mode number of the vertical directional intra prediction mode minus 4, and an intra prediction mode of which mode number is equal to the mode number of the vertical directional intra prediction mode plus 4, and
wherein the MPM candidates which are derived based on a case that one of the first intra prediction mode and the second intra prediction mode is the non-directional intra prediction mode and the other is directional intra prediction mode, comprise:
one of the first intra prediction mode and the second intra prediction mode, an intra prediction mode of which mode number is equal to a maximum mode number of the first intra prediction mode and the second intra prediction mode minus 1, an intra prediction mode of which mode number is equal to the maximum mode number plus 1, an intra prediction mode of which mode number is equal to the maximum mode number minus 2.
2. The method of claim 1 , wherein the non-directional intra prediction mode is a planar intra prediction mode or a DC intra prediction mode, and
the directional intra prediction mode is one of 65 angular intra prediction modes.
3. The method of claim 1 , wherein the first intra prediction mode is derived as an intra prediction mode of the first neighboring block, based on a case that the first neighboring block is available and an intra prediction is applied to the first neighboring block, and
the first intra prediction mode is derived as a planar intra prediction mode, based on a case that the first neighboring block is not available or the intra prediction is not applied to the first neighboring block.
4. The method of claim 1 , wherein the second intra prediction mode is derived as an intra prediction mode of the second neighboring block, based on a case that the second neighboring block is available, an intra prediction is applied to the second neighboring block, and the second neighboring block is included in a current CTU, and
the second intra prediction mode is derived as a planar intra prediction mode, based on a case that the second neighboring block is not available or the intra prediction is not applied to the second neighboring block or the second neighboring block is not included in the current CTU.
5. The method of claim 1 , wherein the method further comprising:
obtaining MPM flag information related to whether the intra prediction mode of the current block is one of the MPM candidates; and
obtaining MPM index information or remaining mode information, based on the MPM flag information,
wherein based on a value of the MPM flag information being 1, the intra prediction mode of the current block is derived based on the MPM index information indicating the intra prediction mode of the current block among the MPM candidates included in the MPM list, or
wherein based on a value of the MPM flag information being 0, the intra prediction mode of the current block is derived based on the remaining mode information indicating the intra prediction mode of the current block excluding the MPM candidates among all available intra prediction modes.
6. The method of claim 5 , wherein the remaining mode information is derived as a value of a syntax element derived based on a Truncated Binary (TB) binarization process.
7. The method of claim 1 , wherein the directional intra prediction mode is one of a horizontal prediction mode, an up-left diagonal prediction mode or a vertical prediction mode.
8. An image encoding method performed by an encoding apparatus, the method comprising:
deriving a first intra prediction mode based on a first neighboring block which is located in a left side of a current block;
deriving a second intra prediction mode based on a second neighboring block which is located in an upper side of the current block;
configuring an Most Probable Mode (MPM) list for the current block based on the first intra prediction mode and the second intra prediction mode;
determining an intra prediction mode of the current block based on the MPM list;
generating prediction samples for the current block based on the intra prediction mode; and
encoding image information including information on the intra prediction mode,
wherein the MPM list comprises MPM candidates derived based on whether at least one of the first intra prediction mode or the second intra prediction mode is non-directional intra prediction mode,
wherein the MPM candidates which are derived based on a case that the first intra prediction mode and the second intra prediction mode are both the non-directional intra prediction mode, comprise:
a DC intra prediction mode, a vertical directional intra prediction mode, a horizontal directional intra prediction mode, an intra prediction mode of which mode number is equal to a mode number of the vertical directional intra prediction mode minus 4, and an intra prediction mode of which mode number is equal to the mode number of the vertical directional intra prediction mode plus 4, and
wherein the MPM candidates which are derived based on a case that one of the first intra prediction mode and the second intra prediction mode is the non-directional intra prediction mode and the other is directional intra prediction mode, comprise:
one of the first intra prediction mode and the second intra prediction mode, an intra prediction mode of which mode number is equal to a maximum mode number of the first intra prediction mode and the second intra prediction mode minus 1, an intra prediction mode of which mode number is equal to the maximum mode number plus 1, an intra prediction mode of which mode number is equal to the maximum mode number minus 2.
9. The method of claim 8 , wherein the non-directional intra prediction mode is a planar intra prediction mode or a DC intra prediction mode, and
the directional intra prediction mode is one of 65 angular intra prediction modes.
10. The method of claim 8 , wherein the first intra prediction mode is derived as an intra prediction mode of the first neighboring block, based on a case that the first neighboring block is available and an intra prediction is applied to the first neighboring block, and
the first intra prediction mode is derived as a planar intra prediction mode, based on a case that the first neighboring block is not available or the intra prediction is not applied to the first neighboring block.
11. The method of claim 8 , wherein the second intra prediction mode is derived as an intra prediction mode of the second neighboring block, based on a case that the second neighboring block is available, an intra prediction is applied to the second neighboring block, and the second neighboring block is included in a current CTU, and
the second intra prediction mode is derived as a planar intra prediction mode, based on a case that the second neighboring block is not available or the intra prediction is not applied to the second neighboring block or the second neighboring block is not included in the current CTU.
12. The method of claim 8 , wherein the directional intra prediction mode is one of a horizontal prediction mode, an up-left diagonal prediction mode or a vertical prediction mode.
13. A non-transitory computer-readable storage medium storing a bitstream generated by a method, the method comprising: performing deriving a first intra prediction mode based on a first neighboring block which is located in a left side of a current block, deriving a second intra prediction mode based on a second neighboring block which is located in an upper side of the current block, configuring an Most Probable Mode (MPM) list for the current block based on the first intra prediction mode and the second intra prediction mode, determining an intra prediction mode of the current block based on the MPM list, generating prediction samples for the current block based on the intra prediction mode, and generating the bitstream by encoding image information including information on the intra prediction mode,
wherein the MPM list comprises MPM candidates derived based on whether at least one of the first intra prediction mode or the second intra prediction mode is non-directional intra prediction mode,
wherein the MPM candidates which are derived based on a case that the first intra prediction mode and the second intra prediction mode are both the non-directional intra prediction mode, comprise:
a DC intra prediction mode, a vertical directional intra prediction mode, a horizontal directional intra prediction mode, an intra prediction mode of which mode number is equal to a mode number of the vertical directional intra prediction mode minus 4, and an intra prediction mode of which mode number is equal to the mode number of the vertical directional intra prediction mode plus 4, and
wherein the MPM candidates which are derived based on a case that one of the first intra prediction mode and the second intra prediction mode is the non-directional intra prediction mode and the other is directional intra prediction mode, comprise:
one of the first intra prediction mode and the second intra prediction mode, an intra prediction mode of which mode number is equal to a maximum mode number of the first intra prediction mode and the second intra prediction mode minus 1, an intra prediction mode of which mode number is equal to the maximum mode number plus 1, an intra prediction mode of which mode number is equal to the maximum mode number minus 2.