HDMI 2.0a is a further update for the High Definition Multimedia Interface. Though a minor change to the interface's specifications – in comparison to the ones made to HDMI cables between versions of the past – HDMI 2.0a can be of significant importance to the future of multimedia content. Version 2.0a has been developed to deal explicitly with the intensive process of sending extended and additional High Dynamic Range content produced by HDR capable source devices to HDR compatible monitors and displays.
Thankfully, HDMI 2.0a is fully compatible with current HDMI cables: no new connectors or additional HDMI cables are needed. In fact, the update has little to do with the HDMI cable at all: HDMI 2.0a concerns the various chips and HDR processing hardware found in source devices such as Ultra HD 4K resolution TVs and Blu-ray players, rather than the HDMI cable transmitting data between them. When discussing TVs, High Dynamic Range is a format that refers to increased realism, greater detail, and better picture quality in terms of how a TV produces video signals. This is due to the hardware possessing a greatly expanded selection of colours including brighter whites, darker blacks and subtle shades of colour. HDR does, however, require a compatible TV and an HDR capable source device, in addition to special, HDR enhanced content.
Ultimately, the HDMI 2.0a update modifies how compatible HDMI source devices communicate static HDR metadata to each other over HDMI cables. This particular set of data is layered over the video signal and is responsible for dictating to the display the most effective ways of rendering the deeper colours, greater contrasts and higher overall picture quality of the HDR content. Despite this, HDMI 2.0a does not regulate how online content is streamed from an Internet connection to a TV: streaming connections such as Netflix bypass HDMI entirely, utilising the TV's decoder instead.