WE CLAIM:
1. An image coding method for generating a coded bitstream by coding an
image, the image coding method comprising:
constructing (S102) a first reference list including a plurality of pictures, each of the pictures having a Picture Order Count (POC) assigned thereto and being identified by one of a plurality of reference indexes, the reference indexes corresponding one to one with the pictures included in the first reference list, each of the reference indexes having a different index value, the first reference list being constructed based on the POC assigned to each of the plurality of pictures;
reordering (S103) the pictures included in the first reference list to generate a modified reference list by assigning new reference indexes using the reference indexes, the new reference indexes corresponding one to one with the pictures included in the modified reference list, each of the new reference indexes having a different index value!
writing (S104), into the coded bitstream, reference list reordering information for indicating details of the reordering; and
coding (S105) the image using the POC assigned to each of the pictures and the modified reference list resulting from the reordering,
wherein each of the reference indexes (i) identifies one of the pictures included in the first reference picture list such that the reference indexes correspond one to one with the pictures included in the first reference list and (ii) is used in assigning the new reference indexes in the reordering.
2. An image decoding method for decoding a coded bitstream, the image
decoding method comprising:
constructing (S202) a first reference list including a plurality of pictures , each of the pictures having a Picture Order Count (POC) assigned thereto and being identified by one of a plurality of reference indexes, the reference indexes corresponding one to one with the pictures included in the first reference list, each of the reference indexes having a different index value, the first reference list being constructed based on the POC assigned to each of the plurality of pictures;
obtaining (S203), from the coded bitstream, reference list reordering information for indicating details of reordering to be performed on the first reference list;
reordering (S204) the pictures included in the first reference list to generate a modified reference list by assigning new reference indexes using the reference indexes, the new reference indexes corresponding one to one with the pictures included in the modified reference list, each of the new reference indexes having a different index value; and
decoding (S205) a current picture or slice using the new reference indexes and the modified reference list resulting from the reordering,
wherein each of the reference indexes (i) identifies one of the pictures included in the first reference picture list such that the reference indexes
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correspond one to one with the pictures included in the first reference list and (ii) is used in assigning the new reference indexes in the reordering.
3. An image coding apparatus (100) for generating a coded bitstream by coding
an image, the image coding apparatus comprising:
a processor (ex500); and
a non-transitory memory (ex511) having stored thereon executable instructions, which when executed by the processor, cause the processor to perform:
constructing (S102) a first reference list including a plurality of pictures, each of the pictures having a Picture Order Count (POC) assigned thereto and being identified by one of a plurality of reference indexes, the reference indexes corresponding one to one with the pictures included in the first reference list, each of the reference indexes having a different index value, the first reference list being constructed based on the POC assigned to each of the plurality of pictures;
reordering (S103) the pictures included in the first reference list to generate a modified reference list by assigning new reference indexes using the reference indexes, the new reference indexes corresponding one to one with the pictures included in the modified reference list, each of the new reference indexes having a different index value!
writing (S104), into the coded bitstream, reference list reordering information for indicating details of the reordering; and
coding (S105) the image using the POC assigned to each of the pictures and the modified reference list resulting from the reordering,
wherein each of the reference indexes (i) identifies one of the pictures included in the first reference picture list such that the reference indexes correspond one to one with the pictures included in the first reference list and (ii) is used in assigning the new reference indexes in the reordering.
4. An image decoding apparatus (200) for decoding a coded bitstream, the image
decoding apparatus comprising:
a processor (ex500); and
a memory (ex51l) having a computer program stored thereon, the computer program causing the processor to execute operations including:
constructing (S202) a first reference list including a plurality of pictures, each of the pictures having a Picture Order Count (POC) assigned thereto and being identified by one of a plurality of reference indexes, the reference indexes corresponding one to one with the pictures included in the first reference list, each of the reference indexes having a different index value, the first reference list being constructed based on the POC assigned to each of the plurality of pictures;
obtaining (S203), from the coded bitstream, reference list reordering information for indicating details of reordering to be performed on the first reference list;
reordering (S204) the pictures included in the first reference list to generate a modified reference list by assigning new reference indexes using the reference
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indexes, the new reference indexes corresponding one to one with the pictures included in the modified reference list, each of the new reference indexes having a different index value! and
decoding (S205) a current picture or slice using the new reference indexes and the modified reference list resulting from the reordering,
wherein each of the reference indexes (i) identifies one of the pictures included in the first reference picture list such that the reference indexes correspond one to one with the pictures included in the first reference list and (ii) is used in assigning the new reference indexes in the reordering.