As an information recording medium that record various contents such as movies, DVDs (Digital Versatile Discs) and BDs (Blu-ray (registered trademark) Discs) are mostly used.
An image, a voice, a caption, other graphic data and the like are recorded on each of the discs in a prescribed data recording format.
On the other hand, a display device, such as a television set, which displays images recorded on these discs, has been improved in resolution because of increase in the number of pixels in recent years.
For example, the television in the past has the number of pixels represented as the number of horizontal pixels &times; the number of vertical pixels=720 &times; 480. And the television in the past can display only SD (Standard Definition) images.
On the other hand, the Hi-vision television which is now widespread has the number of pixels represented as the number of horizontal pixels &times; the number of vertical pixels=1920 &times; 1080. And the Hi-vision television can display HD (High Definition) images (HD contents).
In addition, recently, the 4K television having four times the number of pixels in the HD image, i.e., having, for example, the number of horizontal pixels &times; the number of vertical pixels=4096 &times; 2160, and capable of displaying an image according to the so-called 4K standards (4K format) has been developed and now in a spreading stage.
The 4K television includes a display unit having the number of horizontal pixels &times; the number of vertical pixels=4096 &times; 2160, and is capable of displaying an image (4K image (4K contents) that is four times the HD image in resolution. In addition, a display device that displays an 8K image of a high resolution is also being studied.
As for contents having images of these resolutions, prescriptions in international standards (ITU) are provided with respect to a color space to be used. In other words, a color space corresponding to a color that can be output is prescribed.
As regards the SD image and the HD image, it is prescribed to make contents according to the following color space.
For the SD image, BT. 601, and
for the HD image, BT. 709.
In addition, as for the 4K image, it is demanded to support two color spaces: BT. 2020 and BT. 709. In other words, it is demanded to make contents capable of outputting colors corresponding to at least one of these two color spaces.
Note that, BT. 709 prescribes a color space having a wider color area as compared with BT. 601. In addition, BT. 2020 prescribes a wider color space as compared with BT. 709. The color space prescribed by BT. 2020 is nearly close to a color space observed by naked eyes, and output of natural colors with a higher precision is implemented.
Note that, display of contents having these color spaces is stated in, for example, PTL 1 (JP 2010-263598A) and the like.