Image coding method, image decoding method, image coding apparatus, image decoding apparatus, and image coding and decoding apparatus
A dependency indication is signaled within the beginning of a packet, that is, within the adjacent of a slice header to be parsed or a parameter set. This is achieved, for example, by including the dependency indication at the beginning of the slice header, preferably after a syntax element identifying the parameter set and before the slice address, by including the dependency indication before the slice address, by providing the dependency indication to a NALU header using a separate message, or by using a special NALU type for NALUs carrying dependent slices.
1. An image encoding method for encoding a picture, the image encoding method comprising:
encoding a dependent slice enabling flag which indicates that a dependent slice is either enabled for the picture or is not enabled for the picture, wherein the dependent slice is a slice which is encoded at least partially using control information of a slice different from the dependent slice;
determining a value indicating whether the picture is a random access picture, and,
subsequent to determining that the picture is a random access picture:
encoding, a slice address indicating a starting position of a current slice of the picture; and
only when the dependent slice enabling flag indicates the dependent slice is enabled for the picture, encoding, a dependency indication indicating whether or not the current slice is the dependent slice;
wherein:
the dependent slice enabling flag is disposed in a parameter set common to all slices of the picture;
the slice address is disposed in a slice header of the current slice; and,
the dependency indication is disposed in the slice header of the current slice before the slice address and after a syntax element identifying the parameter set.
2. The image encoding method according to claim 1 , wherein the dependent slice enabling flag is disposed at a beginning of the parameter set.
3. The image encoding method according to claim 1 , wherein the dependency indication is not included in a slice header of a slice which is processed first for the picture.
4. An image encoding apparatus for encoding a picture, the image encoding apparatus comprising:
at least one processor;
at least one memory including computer program code, the memory and the computer program code configured to, working with the at least one processor:
encode a dependent slice enabling flag which indicates that a dependent slice is either enabled for the picture or is not enabled for the picture, wherein the dependent slice is a slice which is encoded at least partially using control information of a slice which is different from the dependent slice;
determine a value indicating whether the picture is a random access picture,
and, subsequent to the determination that the picture is a random access picture:
encode a slice address indicating a starting position of a current slice of the picture; and
only when the dependent slice enabling flag indicates the dependent slice is enabled for the picture, encode, a dependency indication indicating whether or not the current slice is the dependent slice;
wherein:
the dependent slice enabling flag is disposed in a parameter set common to all slices of the picture;
the slice address is disposed in a slice header of the current slice; and
the dependency indication is disposed in the slice header of the current slice before the slice address and after a syntax element identifying the parameter set.
5. The image encoding apparatus according to claim 4 , wherein the dependent slice enabling flag is disposed at a beginning of the parameter set.
6. The image encoding apparatus according to claim 4 , wherein the dependency indication is not included in a slice header of a slice which is processed first for the picture.
7. A non-transitory computer-readable medium storing instructions which, when executed by a processor, perform the acts of:
encoding a dependent slice enabling flag which indicates that a dependent slice is either enabled for the picture or is not enabled for the picture, wherein the dependent slice is a slice which is encoded at least partially using control information of a slice which is different from the dependent slice;
determining a value indicating whether the picture is a random access picture, and, subsequent to determining whether the picture is a random access picture:
encoding a slice address indicating a starting position of a current slice of the picture; and
only when the dependent slice enabling flag indicates the dependent slice is enabled for the picture, encoding, a dependency indication indicating whether or not the current slice is the dependent slice;
wherein:
the dependent slice enabling flag is disposed in a parameter set common to all slices of the picture;
the slice address is disposed in a slice header of the current slice; and
the dependency indication is disposed in the slice header of the current slice before the slice address and after a syntax element identifying the parameter set.
8. The non-transitory computer-readable medium according to claim 7 , wherein the dependent slice enabling flag is disposed at a beginning of the parameter set.
9. The non-transitory computer-readable medium according to claim 7 , wherein the dependency indication is not included in a slice header of a slice which is processed first for the picture.