Method and apparatus for video coding
Aspects of the disclosure provide a method and an apparatus for video coding. In some examples, an apparatus includes processing circuitry that divides a current block into a plurality of sub-blocks, derives a plurality of pieces of sub-block motion information for the plurality of sub-blocks, generates predicted sub-block samples for the sub-blocks according to the pieces of sub-block motion information, and generates a predicted block for the current block according to a combination of the predicted sub-block samples. The processing circuitry also selects a piece of the sub-block motion information from the pieces of sub-block motion information as representative motion information for the current block, and stores the representative motion information in a history-based motion vector prediction (HMVP) buffer.
1. A method of video decoding in a decoder, comprising
dividing a current block into a plurality of sub-blocks:
deriving a plurality of pieces of sub-block motion information for the plurality of sub-blocks, respectively:
generating predicted sub-block samples for the sub-blocks according to the pieces of sub-block motion information;
generating a predicted block for the current block according to a combination of the predicted sub-block samples:
selecting a piece of sub-block motion information that corresponds to a particular sub-block of the plurality of sub-blocks from the pieces of sub-block motion information as representative motion information for the current block to be stored as a new history-based motion vector prediction (HMVP) candidate in an HMVP buffer; and
after the predicted block for the current block is generated, storing the representative motion information for the current block as the new HMVP candidate in the HMVP buffer for a subsequent motion vector prediction process.
2. The method of claim 1 , wherein
the particular sub-block of the plurality of sub-blocks is at a particular position in the current block.
3. The method of claim 2 , wherein
the particular sub-block is at a bottom-right position in the current block.
4. The method of claim 2 , wherein
the particular sub-block is adjacent to a center position of the current block.
5. The method of claim 4 , wherein
an upper-left corner of the particular sub-block is at the center position of the current block.
6. The method of claim 2 , further comprising:
determining the particular position according to control information transmitted in a Sequence Parameter Set (SPS), Picture Parameter Set (PPS), slice header, tile group header, or tile header.
7. The method of claim 1 , wherein
the current block is coded according to one of affine inter prediction, subblock-based temporal motion vector prediction, and triangular inter prediction.
8. An apparatus, comprising:
processing circuitry configured to:
divide a current block into a plurality of sub-blocks;
derive a plurality of pieces of sub-block motion information for the plurality of sub-blocks, respectively;
generate predicted sub-block samples for the sub-blocks according to the pieces of sub-block motion information;
generate a predicted block for the current block according to a combination of the predicted sub-block samples;
select a piece of sub-block motion information that corresponds to a particular sub-block of the plurality of sub-blocks from the pieces of sub-block motion information as representative motion information for the current block to be stored as a new history-based motion vector prediction (HMVP) candidate in an HMVP buffer; and
after the predicted block for the current block is generated, store the representative motion information for the current block as the new HMVP candidate in the HMVP buffer for a subsequent motion vector prediction process.
9. The apparatus of claim 8 , wherein
the particular sub-block of the plurality of sub-blocks is at a particular position in the current block.
10. The apparatus of claim 9 , wherein
the particular sub-block is at a bottom-right position in the current block.
11. The apparatus of claim 9 , wherein
the particular sub-block is adjacent to a center position of the current block.
12. The apparatus of claim 11 , wherein
an upper-left corner of the particular sub-block is at the center position of the current block.
13. The apparatus of claim 9 , wherein the processing circuitry is further configured to:
determine the particular position according to control information transmitted in a Sequence Parameter Set (SPS), Picture Parameter Set (PPS), slice header, tile group header, or tile header.
14. The apparatus of claim 8 , wherein
the current block is coded according to one of affine inter prediction, subblock-based temporal motion vector prediction, and triangular inter prediction.
15. A non-transitory computer-readable medium storing instructions which when executed by a computer for video decoding cause the computer to perform:
dividing a current block into a plurality of sub-blocks;
deriving a plurality of pieces of sub-block motion information for the plurality of sub-blocks, respectively;
generating predicted sub-block samples for the sub-blocks according to the pieces of sub-block motion information;
generating a predicted block for the current block according to a combination of the predicted sub-block samples;
selecting a piece of sub-block motion information that corresponds to a particular sub-block of the plurality of sub-blocks from the pieces of sub-block motion information as representative motion information for the current block to be stored as a new history-based motion vector prediction (HMVP) candidate in an HMVP buffer; and
after the predicted block for the cu rent block is generated, storing the representative motion information for the current block as the new HMVP candidate in the HMVP buffer for a subsequent motion vector prediction process.
16. The non-transitory computer-readable medium of claim 15 , wherein
the particular sub-block of the plurality of sub-blocks is at a particular position the current block.
17. The non-transitory computer-readable medium of claim 16 , wherein
the particular sub-block is at a bottom-right position in the current block.
18. The non-transitory computer-readable medium of claim 16 , wherein
the particular sub-block is adjacent to a center position of the current block, and
an upper-left corner of the particular sub-block is at the center position of the current block.
19. The non-transitory computer-readable medium of claim 16 , wherein the instructions when executed by the computer further cause the computer to perform:
determining the particular position according to control information transmitted in a Sequence Parameter Set (SPS), Picture Parameter Set (PPS), slice header, tile group header, or tile header.
20. The non-transitory computer-readable medium of claim 15 , wherein
the current block is coded according to one of affine inter prediction, subblock-based temporal motion vector prediction, and triangular inter prediction.
21. The method of claim 1 , wherein
the HMVP buffer is configured to store up to six HMVP candidates.