Merge candidates with multiple hypothesis
A video decoder receives to-be-decoded data from a bitstream for a block of pixels to be decoded as a current block of a current picture of the video. The video decoder generates a first prediction of the current block based on a first prediction mode that is selected from a first candidate list. The video decoder generates a second prediction of the current block based on a second prediction mode that is selected from a second candidate list. The video decoder generates a combined prediction for the current block based on the first prediction and the second prediction. The video decoder reconstructs the current block by using the combined prediction.
1. A video coding method, comprising:
receiving data to be encoded or decoded as a current block of a current picture of a video;
generating a first prediction of the current block according to an inter-prediction mode and a first selected motion candidate selected from a candidate list, the candidate list including one or more motion candidates;
generating a second prediction of the current block according to the inter-prediction mode and a second selected motion candidate selected from the candidate list, or according to a selected intra-prediction mode selected from one or more candidate intra-prediction modes that include a directional intra-prediction mode, a DC mode, or a Planar mode;
generating a combined prediction for the current block based on the first prediction and the second prediction; and
encoding the current block into a bitstream or reconstructing the current block according to the combined prediction,
wherein
the combined prediction is applicable to a sub-region of the current block and not applicable outside of the sub-region of the current block, and
a size of the sub-region is determined based on a width, height, or size of the current block.
2. The method of claim 1 , wherein the candidate list is a merge candidate list of the current block or a subset of the merge candidate list of the current block.
3. The method of claim 1 , wherein the second prediction is generated according to the selected intra-prediction mode that is selected based on an ordering of the one or more candidate intra-prediction modes that is determined based on the width, the height, or the size of the current block.
4. The method of claim 1 , wherein selection information for the first selected motion candidate, the second selected motion candidate, or the selected intra-prediction mode is signaled by using a shortest code word.
5. The method of claim 1 , wherein the one or more candidate intra-prediction modes include only one candidate intra-prediction mode.
6. The method of claim 5 , wherein the only one candidate intra-prediction mode is identified based on a ratio between a width of the current block and a height of the current block.
7. An apparatus, comprising:
processing circuitry configured to:
receive data to be encoded or decoded as a current block of a current picture of a video;
generate a first prediction of the current block according to an inter-prediction mode and a first selected motion candidate selected from a candidate list, the candidate list including one or more motion candidates;
generate a second prediction of the current block according to the inter-prediction mode and a second selected motion candidate selected from the candidate list, or according to a selected intra-prediction mode selected from one or more candidate intra-prediction modes that include a directional intra-prediction mode, a DC mode, or a Planar mode;
generate a combined prediction for the current block based on the first prediction and the second prediction; and
encode the current block into a bitstream or reconstructing the current block according to the combined prediction,
wherein
the combined prediction is applicable to a sub-region of the current block and not applicable outside of the sub-region of the current block, and
a size of the sub-region is determined based on a width, height, or size of the current block.
8. The apparatus of claim 7 , wherein the candidate list is a merge candidate list of the current block or a subset of the merge candidate list of the current block.
9. The apparatus of claim 7 , wherein the second prediction is generated according to the selected intra-prediction mode that is selected based on an ordering of the one or more candidate intra-prediction modes that is determined based on the width, the height, or the size of the current block.
10. The apparatus of claim 7 , wherein selection information for the first selected motion candidate, the second selected motion candidate, or the selected intra-prediction mode is signaled by using a shortest code word.
11. The apparatus of claim 7 , wherein the one or more candidate intra-prediction modes include only one candidate intra-prediction mode.
12. The apparatus of claim 11 , wherein the only one candidate intra-prediction mode is identified based on a ratio between a width of the current block and a height of the current block.