By Darryl Budge
The central feature of a 4K UHD screen is a four-fold increase in resolution over Full HD (1080p). The pixel dimensions are 3840 by 2160 (8.3 million pixels) vs. Full HD 1920x1080 resolution (2.2 million pixels). All 4KTVs upscale lower resolutions.
Buying a TV for the "4K" label alone does not guarantee greater image contrast, black levels or colour range. These improvements rely on other new technologies. For example, 'HDR' extends the brightness and colour range. 'Quantum dots' (coloured nanocrystals on the edge or behind the whole screen) increase colour vibrancy. Very expensive Organic LED (OLED) displays are superior in every way (even better than Plasma). Many such technologies are included in new 4K TVs.
HOW CLOSE DO YOU SIT? The benefit of 4K resolution shines in screens above 55 inches from less than 2 metres away (65inch=2.5m). If you sit further away, you will not see much, if any, difference in detail when playing 4K content. However, a 4K screen could double as a TV and a 'sit-close' PC monitor in small living spaces.
HOW DO I GET 4K CONTENT (apart from shooting 4k mobile phone videos)?
Netflix 4K: requires the $15 monthly plan, a 4K 'smart TV' with the 'High Efficiency Video Codec' (H.265) and built-in Netflix app, and a broadband connection above 15 megabits per second. Watching 14 hours (of the 60+ hours available) of 4K Netflix will use 100 gigabytes of internet quota. If your ISP is Internode, iiNet, Westnet, Adam or Optus, Netflix is unlimited in quota. Unfortunately playing 4K Netflix via a computer requires a very new and expensive graphics card that supports HVEC and HDCP 2.2 copy protection.
YouTube 4K: Using a different codec called VP9, 4K YouTube content is not yet common, even though some high-end mobile phones record 4K videos. This will change when YouTube launches a paid subscription streaming service. Unlike HVEC, the VP9 codec is open-source and can be played on a 4K TV with the YouTube app, or a 4K computer monitor using Google Chrome or Firefox browsers.
Ultra HD Blu-ray: Later this year, 3-layer Ultra HD Blu-ray discs with up to 100GB of storage will offer 4K content and up to 11.3 surround sound. These discs can offer 60 fps video, 10-bit colour graduation (1024 levels of brightness, vs 256 for 8-bit) and a wider colour gamut (i.e. palette) called Rec. 2020. To play these discs you will need to buy a new Ultra HD Blu-ray disc player (that is backwards compatible) and have a 4K TV that supports HVEC, HDMI 2.0 and HDCP 2.2.
WHEN TO BUY? 4K Ultra HD televisions are expected to enter mainstream demand from Christmas 2015. Waiting those few months means prices will drop further. Make sure it supports at least the HVEC codec, HDMI 2.0 and HDCP 2.2 copy protection. To see the best of UHD Blu-ray, choose a 10-bit colour panel as well.