In the expression, L is the luminance of an image and standardized at a reference white level, where V may exceed 1, meaning that this conversion function also supports luminance greater than the reference white, V is a numerical value corresponding to an electric signal, μ is a breakpoint between a gamma curve and a logarithmic curve and determines the maximum value of L where V is 1 or less, and α, β, γ, δ, and ρ are each a constant and specific numerical examples thereof are α=4.5, β=0.018, γ=1.099, δ=0.45, and ρ=0.099.

In other words, as represented by Expression 4, the second OETF may be an OETF defined by a linear term of the luminance of video data in a third range of the luminance of the video data, defined by an exponential term of the luminance of the video data in a fourth range of the luminance of the video data greater than the third range, and defined by a logarithmic term of the luminance of the video data in a fifth range of the luminance of the video data greater than the fourth range.

The first OETF may be the function determined according to Expression 5 below.
[Math. 4]
V=L^α??(Expression 5)