Image coding apparatus and method, and image decoding apparatus and method

1. An image coding apparatus comprising:

circuitry configured to:

set, in a case where a number of enhancement layers of an image is greater than a number of candidates for resolution information on a layer of the image, a correspondence relationship between each of the candidates and at least one of the enhancement layers so that at least one of the candidates correspond to at least two of the enhancement layers;

set, in a case where the number of the candidates is greater than the number of the enhancement layers, the correspondence relationship between the candidates and the enhancement layers so that a one-to-one correspondence is established between the candidates and the enhancement layers, beginning with a leading candidate; and

code the image and generate a bitstream including information relating to the set correspondence relationship,

wherein each of the enhancement layers is set to correspond to at least one of the candidates.

2. The image coding apparatus according to claim 1 , wherein, in a case where multiple candidates are present, information is set that indicates whether or not the correspondence relationship between the resolution information and the enhancement layer is present.

3. The image coding apparatus according to claim 1 , wherein, in a case where the number of the candidates is 1, updating of the correspondence relationship between the resolution information and the enhancement layer is prohibited in a sequence parameter set.

4. The image coding apparatus according to claim 1 , wherein the one-to-one correspondence is established between the candidates and the enhancement layers, beginning with a leading candidate, so that at least one of the candidates do not correspond to at least two of the enhancement layers.

5. An image coding method comprising:

setting, in a case where a number of enhancement layers of an image is greater than a number of candidates for resolution information on a layer of the image, a correspondence relationship between each of the candidates and at least one of the enhancement layers so that at least one of the candidates correspond to at least two of the enhancement layers;

setting, in a case where the number of the candidates is greater than the number of the enhancement layers, the correspondence relationship between the candidates and the enhancement layers so that a one-to-one correspondence is established between the candidates and the enhancement layers, beginning with a leading candidate; and

coding the image and generating a bitstream including information relating to the correspondence relationship that is set,

wherein each of the enhancement layers is set to correspond to at least one of the candidates.

6. A non-transitory computer-readable medium having embodied thereon a program, which when executed by a computer causes the computer to execute an image coding method, the method comprising:

setting, in a case where a number of enhancement layers of an image is greater than a number of candidates for resolution information on a layer of the image, a correspondence relationship between each of the candidates and at least one of the enhancement layers so that at least one of the candidates correspond to at least two of the enhancement layers;

setting, in a case where the number of the candidates is greater than the number of the enhancement layers, the correspondence relationship between the candidates and the enhancement layers so that a one-to-one correspondence is established between the candidates and the enhancement layers, beginning with a leading candidate; and

coding the image and generating a bitstream including information relating to the correspondence relationship that is set,

wherein each of the enhancement layers is set to correspond to at least one of the candidates.

7. An image coding apparatus comprising:

a setting unit configured to:

set, in a case where a number of enhancement layers of an image is greater than a number of candidates for resolution information on a layer of the image, a correspondence relationship between each of the candidates and at least one of the enhancement layers so that at least one of the candidates correspond to at least two of the enhancement layers; and

set, in a case where the number of the candidates is greater than the number of the enhancement layers, the correspondence relationship between the candidates and the enhancement layers so that a one-to-one correspondence is established between the candidates and the enhancement layers, beginning with a leading candidate; and

a coding unit configured to code the image and generate a bitstream including information relating to the correspondence relationship that is set by the setting unit,

wherein each of the enhancement layers is set to correspond to at least one of the candidates, and

wherein the setting unit and the coding unit are each implemented via at least one processor.

8. The image coding apparatus according to claim 7 , wherein, in a case where multiple candidates are present, the setting unit sets information that indicates whether or not the correspondence relationship between the resolution information and the enhancement layer is present.

9. The image coding apparatus according to claim 7 , wherein, in a case where the number of the candidates is 1, the setting unit prohibits updating of the correspondence relationship between the resolution information and the enhancement layer in a sequence parameter set.

10. An image coding apparatus comprising:

circuitry configured to:

set, in a case where a number of enhancement layers of an image is greater than a number of candidates for resolution information on a layer of the image, a correspondence relationship between each of the candidates and at least one of the enhancement layers so that at least one of the candidates correspond to at least two of the enhancement layers;

set, in a case where the number of the candidates is greater than the number of the enhancement layers, the correspondence relationship between the candidates and the enhancement layers so that a one-to-one correspondence is established between the candidates and the enhancement layers, beginning with a leading candidate;

automatically map the enhancement layers and the candidates onto each other; and

code the image and generate a bitstream including information relating to the set correspondence relationship,

wherein each of the enhancement layers is set to correspond to at least one of the candidates.

11. An image coding apparatus comprising:

circuitry configured to:

set, in a case where a number of Rep_formats on a layer of an image is less than a number of enhancement layers of the image, a correspondence relationship between each of the Rep_formats and at least one of the enhancement layers so that at least one of the Rep_formats correspond to at least two of the enhancement layers;

set, in a case where the number of the Rep_formats is greater than the number of the enhancement layers, the correspondence relationship between the Rep_formats and the enhancement layers so that a one-to-one correspondence is established between the Rep_formats and the enhancement layers, beginning with a leading candidate; and

code the image and generate a bitstream including information relating to the set correspondence relationship,

wherein, in a case where the number of the Rep_formats is less than the number of the enhancement layers, the correspondence relationship between the Rep_formats and the enhancement layers is set, beginning with the leading candidate, and an automatic mapping is performed between the Rep_formats and the enhancement layers, and

wherein each of the enhancement layers is set to correspond to at least one of the Rep_formats.