Encoder, decoder, encoding method, and decoding method
An image encoder/decoder includes circuitry and a memory coupled to the circuitry. When a geometry of a block of a picture satisfies a first condition, the circuitry splits the block of the picture into sub blocks having a first set of geometries. When the geometry of the block does not satisfy the first condition, the circuitry splits the block of the picture into sub blocks having a second set of geometries, the second set of geometries being different from the first set of geometries. The circuitry encodes/decodes the sub blocks of the block.
1 . An image encoder, comprising:
circuitry; and
a memory coupled to the circuitry,
wherein the circuitry, in operation,
splits a block of a picture into four sub blocks if a determined number of sub blocks for the block is set to four, wherein
(a) if a size of the block satisfies a block-size condition, the block is split along a single direction, wherein:
(i) if the block has a width larger than its height and a size of 32×8, the block is split along a vertical direction into four 8×8 sub blocks; and
(ii) if the block has a height larger than its width and a size of 8×32, the block is split along a horizontal direction into four 8×8 sub blocks; and
(b) if the size of the block does not satisfy the block-size condition, the block is split along vertical and horizontal directions, wherein if the block has a width equal to its height and a size of 32×32, the block is split into four 16×16 sub blocks; and
encodes the sub blocks.
2 . An image decoder, comprising:
circuitry; and
a memory coupled to the circuitry,
wherein the circuitry, in operation,
splits a block of a picture into four sub blocks if a determined number of sub blocks for the block is set to four, wherein
(a) if a size of the block satisfies a block-size condition, the block is split along a single direction, wherein:
(i) if the block has a width larger than its height and a size of 32×8, the block is split along a vertical direction into four 8×8 sub blocks; and
(ii) if the block has a height larger than its width and a size of 8×32, the block is split along a horizontal direction into four 8×8 sub blocks; and
(b) if the size of the block does not satisfy the block-size condition, the block is split along vertical and horizontal directions, wherein if the block has a width equal to its height and a size of 32×32, the block is split into four 16×16 sub blocks; and
decodes the sub blocks.
3 . A bitstream transmitting apparatus, comprising:
circuitry; and
memory coupled to the circuitry,
wherein the circuitry, in operation:
transmits a bitstream generated by performing an encoding method, the encoding method including:
splitting a block of a picture into four sub blocks if a determined number of sub blocks for the block is set to four, wherein the step of splitting the block comprises:
(a) if a size of the block satisfies a block-size condition, splitting the block along a single direction, wherein:
(i) if the block has a width larger than its height and a size of 32×8, the block is split along a vertical direction into four 8×8 sub blocks; and
(ii) if the block has a height larger than its width and a size of 8×32, the block is split along a horizontal direction into four 8×8 sub blocks; and
(b) if the size of the block does not satisfy the block-size condition, splitting the block along vertical and horizontal directions, wherein if the block has a width equal to its height and a size of 32×32, the block is split into four 16×16 sub blocks; and
encoding the sub blocks.