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 of performing encoding processing of a picture on a slice basis, the image encoding method comprising:
encoding, into a bitstream, a dependent slice enabling flag indicating whether or not a dependent slice is enabled for the picture, wherein the dependent slice is a slice on which the encoding processing is performed by partially using control information included in a header of a slice different from the dependent slice,
encoding, into the bitstream, a slice address indicating a starting position of a current slice of the picture, and
encoding, into the bitstream, a dependency indication indicating whether or not the current slice is the dependent slice;
wherein, when the dependency indication indicates the slice is an independent slice, a context table of arithmetic encoding is initialized,
when the dependency indication indicates the slice is the dependent slice, the context table of arithmetic encoding is not initialized,
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 dependency indication is encoded into the bitstream when the dependent slice enabling flag indicates the dependent slice is enabled for the picture.
3. The image encoding method according to claim 1 , wherein the dependent slice enabling flag is disposed at a beginning of the parameter set.
4. 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.
5. The image encoding method according to claim 1 , wherein the encoding of the dependent slice does not initialize CABAC context tables.
6. The image encoding method according to claim 1 , wherein the encoding of the slice different from the dependent slice initializes CABAC context tables.
7. An image encoding apparatus which performs encoding processing of a picture on a slice basis, the image encoding apparatus comprising:
an encoder, which encodes into a bitstream:
a dependent slice enabling flag indicating whether or not a dependent slice is enabled for the picture, wherein the dependent slice is a slice on which the encoding processing is performed by partially using control information included in a header of a slice different from the dependent slice, a slice address indicating a starting position of a current slice of the picture, and
a dependency indication indicating whether or not the current slice is the dependent slice;
wherein, when the dependency indication indicates the slice is an independent slice, a context table of arithmetic encoding is initialized,
when the dependency indication indicates the slice is the dependent slice, the context table of arithmetic encoding is not initialized,
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.