Coding method and coding apparatus
The image decoding method includes: determining a context for use in a current block to be processed, from among a plurality of contexts; and performing arithmetic decoding on a bit sequence corresponding to the current block, using the determined context, wherein in the determining: the context is determined under a condition that control parameters of neighboring blocks of the current block are used, when the signal type is a first type, the neighboring blocks being a left block and an upper block of the current block; and the context is determined under a condition that the control parameter of the upper block is not used, when the signal type is a second type, and the second type is one of “ref_idx_l0” and “ref_idx_l1”.
1 . A non-transitory computer-readable medium storing thereon a computer program for decoding a control parameter for controlling decoding of an image, the computer program being executed by a processor, causing the processor to perform operations including:
determining a context for a current block in the image, from among a plurality of contexts; and
performing arithmetic decoding on a bitstream corresponding to the current block, using the determined context to obtain the control parameter for the current block,
wherein the determining further includes:
determining a signal type under which the control parameter for the current block is classified;
determining the context by using both of decoded control parameters for a left block and an upper block, when the signal type is a first type, the left block being a neighboring block to the left of the current block, and the upper block being a neighboring block on top of the current block; and
determining the context by using a predetermined fixed value, without using any decoded control parameters for the left block and the upper block, when the signal type is a second type different from the first type,
wherein a split flag is classified under the first type, the split flag indicating whether or not the current block is partitioned into a plurality of blocks, and
wherein a reference picture index is classified under the second type, the reference picture index indicating a reference picture used to predict the current block.
2 . A non-transitory computer-readable medium storing thereon a computer program for coding a control parameter for controlling coding of an image, the computer program being executed by a processor, causing the processor to perform operations including:
determining a context for a current block in the image, from among a plurality of contexts; and
performing arithmetic coding on the control parameter for the current block, using the determined context to generate a bitstream corresponding to the current block,
wherein the determining further includes:
determining a signal type under which the control parameter for the current block is classified;
determining the context by using both of coded control parameters for a left block and an upper block, when the signal type is a first type, the left block being a neighboring block to the left of the current block, and the upper block being a neighboring block on top of the current block; and
determining the context by using a predetermined fixed value, without using any coded control parameters for the left block and the upper block, when the signal type is a second type different from the first type,
wherein a split flag is classified under the first type, the split flag indicating whether or not the current block is partitioned into a plurality of blocks, and
wherein a reference picture index is classified under the second type, the reference picture index indicating a reference picture used to predict the current block.
3 . A non-transitory computer-readable medium storing executable instructions for causing a computer to perform an encoding method to generate a bitstream to be stored on the non-transitory computer readable medium, the encoding method comprising:
determining a context for a current block in the image, from among a plurality of contexts; and
performing arithmetic coding on the control parameter for the current block, using the determined context to generate a bitstream corresponding to the current block,
wherein the determining further includes:
determining a signal type under which the control parameter for the current block is classified;
determining the context by using both of coded control parameters for a left block and an upper block, when the signal type is a first type, the left block being a neighboring block to the left of the current block, and the upper block being a neighboring block on top of the current block; and
determining the context by using a predetermined fixed value, without using any coded control parameters for the left block and the upper block, when the signal type is a second type different from the first type,
wherein a split flag is classified under the first type, the split flag indicating whether or not the current block is partitioned into a plurality of blocks, and
wherein a reference picture index is classified under the second type, the reference picture index indicating a reference picture used to predict the current block.