Video processing

A method comprising:

• providing output video images to a head mountable display, HMD, having one or more display elements to display video images to a wearer of the HMD, for display by the one or more display elements in response to input video images, in which each output video image corresponds to a respective input video image;
• detecting whether an input image brightness at image locations in the input video images exceeds a threshold image brightness;
• and
• varying a relationship between display properties at a given image location in a given output video image and the input image display properties at the given image location in the corresponding input video image in response to a detection that image brightness at the given image location in one or more input video images preceding that corresponding input video image exceeded the threshold image brightness.

A non-transitory, machine-readable storage medium which stores computer software which, when executed by a computer, causes the computer to perform a method comprising:

• providing output video images to a head mountable display, HMD, having one or more display elements to display video images to a wearer of the HMD, for display by the one or more display elements in response to input video images, in which each output video image corresponds to a respective input video image;
• detecting whether an input image brightness at image locations in the input video images exceeds a threshold image brightness;
• and
• varying a relationship between display properties at a given image location in a given output video image and the input image display properties at the given image location in the corresponding input video image in response to a detection that image brightness at the given image location in one or more input video images preceding that corresponding input video image exceeded the threshold image brightness.