Apparatus for driving a local-dimming display comprising a backlight and a spatial light modulator, the backlight comprising a plurality of individually controllable elements, the apparatus comprising: a decoder configured to extract: (i) a first image data component comprising a lower dynamic range version of an image from which first driving signals for the spatial light modulator are derivable; and (ii) a second image data component comprising a ratio data image from which second driving signals for controlling the individually controllable elements of the backlight are derivable, the ratio data image having pixel values that are ratios of a pixel value of a higher dynamic range version of the image to a pixel value of the lower dynamic range version of the image; a first system configured to generate, using the first image data component and without combining the first image data component with the second image data component, the first driving signals for the spatial light modulator; and a second system configured to generate, using the second image data component and without combining the first image data component with the second image data component, the second driving signals for controlling the individually controllable elements of the backlight; wherein a signal path in which the first image data component is processed by the first system and a signal path in which the second image data component is processed by the second system have no connection with each other; wherein the first driving signals and the second driving signals cause the local-dimming display to display the higher dynamic range version of the image; and wherein the second system comprises a downsampler configured to downsample the second image data component to a resolution of the individually controllable element of the backlight, such that Pixel values of the downsampled second image data component comprise driving values of the second driving signal, wherein the ratio data image has a resolution greater than the resolution of the individually controllable elements of the backlight. a decoder configured to extract: (i) a first image data component comprising a lower dynamic range version of an image from which first driving signals for the spatial light modulator are derivable; and (ii) a second image data component comprising a ratio data image from which second driving signals for controlling the individually controllable elements of the backlight are derivable, the ratio data image having pixel values that are ratios of a pixel value of a higher dynamic range version of the image to a pixel value of the lower dynamic range version of the image; a first system configured to generate, using the first image data component and without combining the first image data component with the second image data component, the first driving signals for the spatial light modulator; and a second system configured to generate, using the second image data component and without combining the first image data component with the second image data component, the second driving signals for controlling the individually controllable elements of the backlight; wherein a signal path in which the first image data component is processed by the first system and a signal path in which the second image data component is processed by the second system have no connection with each other; wherein the first driving signals and the second driving signals cause the local-dimming display to display the higher dynamic range version of the image; and wherein the second system comprises a downsampler configured to downsample the second image data component to a resolution of the individually controllable element of the backlight, such that Pixel values of the downsampled second image data component comprise driving values of the second driving signal, wherein the ratio data image has a resolution greater than the resolution of the individually controllable elements of the backlight. system and a signal path in which the second image data component is processed by the second system have no connection with each other; wherein the first driving signals and the second driving signals cause the local-dimming display to display the higher dynamic range version of the image; and wherein the second system comprises a downsampler configured to downsample the second image data component to a resolution of the individually controllable element of the backlight, such that Pixel values of the downsampled second image data component comprise driving values of the second driving signal, wherein the ratio data image has a resolution greater than the resolution of the individually controllable elements of the backlight.