Patent ID: 11949903
Assignee: SUN PATENT TRUST
Field: Audio-visual technology (Electrical engineering)
Classification: CPC H | IPC H

Claim 0:
1. An image coding system, comprising:
an encoding apparatus that encodes a current block, the image encoding apparatus including:
a processor;
a memory storing instructions, which when executed by the processor cause the apparatus to:
encode information in a slice header indicative of a maximum number of merging candidates, wherein the slice header corresponds to a slice containing a plurality of blocks including the current block;
derive a plurality of merging candidates for encoding the current block from a corresponding plurality of blocks that are neighbor or co-located blocks of the current block, each of the plurality of merging candidates having a motion vector for encoding a corresponding one of the plurality of blocks, a prediction direction that corresponds to the corresponding one of the plurality of blocks, and a reference picture index that identifies a reference picture corresponding to the corresponding one of the plurality of blocks;
determine whether a number of the plurality of merging candidates for encoding the current block is less than the maximum number of merging candidates;
when it is determined that the number of the plurality of merging candidates for encoding the current block is less than the maximum number of merging candidates, derive at least one combined candidate for bi-directional prediction, by:
assigning the motion vector and the reference picture index of a first merging candidate of the plurality of merging candidates for encoding the current block to a first prediction direction of the at least one combined candidate; and
assigning the motion vector and the reference picture index of a second merging candidate of the plurality of merging candidates for encoding the current block to a second prediction direction of the at least one combined candidate;

select a candidate from the plurality of merging candidates and the at least one combined candidate;
encode an index corresponding to the selected candidate, wherein the maximum number of merging candidates is used to encode the index; and
encode the current block using the selected candidate; and

an image decoding apparatus that decodes the current block, the image decoding apparatus including:
a processor;
a memory storing instructions, which when executed by the processor cause the apparatus to:
decode information from the slice header indicative of a maximum number of merging candidates;
derive a plurality of merging candidates for decoding the current block from a corresponding plurality of blocks that are neighbor or co-located blocks of the current block, each of the plurality of merging candidates for decoding the current block having a motion vector for decoding a corresponding one of the plurality of blocks, a prediction direction that corresponds to the motion vector for decoding the corresponding one of the plurality of blocks, and a reference picture index that identifies a reference picture corresponding to the motion vector for decoding the corresponding one of the plurality of blocks;
determine whether a number of the plurality of merging candidates for decoding the current block is less than the maximum number of merging candidates;
when it is determined that the number of the plurality of merging candidates for decoding the current block is less than the maximum number of merging candidates, derive a combined merging candidate for bi-directional prediction for decoding the current block, whereby the memory comprises instructions which, when executed by the processor cause the apparatus to:
assign the motion vector for decoding the corresponding block and the reference picture index of a first merging candidate of the plurality of merging candidates for decoding the current block to a first prediction direction of the combined merging candidate for decoding the current block; and
assign the motion vector for decoding the corresponding block and the reference picture index of a second merging candidate of the plurality of merging candidates for decoding the current block to a second prediction direction of the combined merging candidate for decoding the current block; and

decode the current block using a candidate selected from the plurality of merging candidates and the combined merging candidate.