match' texture descriptor. Generically, all images are converted into a common unified format in which image features are identified based on the wavelength of the colours making up the scene, expressed as a standardised 63-bit descriptor. Some of the more complex algorithms, for example automated face-recognition algorithms, require more accuracy and resolution and use a 253-bit descriptor. Video descriptions are based on a differentiation of simple scenes and complex scenes together with motion estimation using vectors (direction and magnitude). In a perfect world, this all works with present and proposed MPEG-4-based object coding, though in practice it is still problematic to extract meaningful video objects out of a high frame rate high-resolution video. These are nontrivial processing tasks not to be attempted seriously in embedded software and are presently better performed as a server-side function (potentially good news for network operator and server added value). Cameras and camera phones equipped with depth sensors and/ or twin camera stereoptic capture makes it easier to capture 3D video and segmented objects that in turn make object- based coding more useful. These at present represent a specialised but emerging application sector. Thus, MPEG 7 marks a useful start in terms of a standards process but there is much practical work still to be done. 10.11 Mobile Metadata and the Five Domains of User Value The fact that we have not arrived at an end destination does not mean we cannot enjoy the journey and mobile metadata already has much to offer in terms of 'interconnected user domain value'. To summarise: The Radio system domain, mobile metadata can extract value from cell ID, di- rection and speed of movement and all of the other (many) user-specific behaviour metrics that are potentially available from the radio air interface. This value can be realised by integration with parallel mobile metadata inputs including: The Audio domain mobile metadata can be associated with voice capture and voice reco