Images and videos use specific transfer functions to describe the relationship between electrical signal, scene light and displayed light.
The opto-electronic transfer function (OETF) is the transfer function having the scene light as input and converting into the picture or video signal as output.
[1] The electro-optical transfer function (EOTF) is the transfer function having the picture or video signal as input and converting it into the linear light output of the display.
The opto-optical transfer function (OOTF) is the transfer function having the scene light as input and the displayed light as output.
[1] These transfer functions have been developed to allow HDR display: