Codec system and method

Abstract

Image codec with server and client device system, and method for encoding images with photoreal and non-photoreal parts to assist with visual impairment. Rendering includes detecting image regions with predetermined properties s510 and logging the property as a reserved value stored on an alpha channel s520. Encoding s530 incorporates settings selected in response to the reserved value s535. Settings may be other than the default and an encoded image produced with indicators of selectable changes to decoder settings. The decoder can select changes in response to predetermined indicators. The predetermined property may relate to image modification responding to; a user accessibility requirement like the colour range or gamut being reduced or altered, discontinuities of colour, brightness, or contrast, other accessibility indicators, or; rendering, sourcing from a real-world image, animation or motion, inter-image difference of pixel values while accounting for inter-image motion or not, decoded image quality, or intended quality degradation. An image region may correspond to; an encoding block, set of pixels corresponding to one alpha channel pixel, depicted object, or to a modification. [Figure 5]