When you plug your Blu-ray player, games console or media streaming box into a shiny new Full HD or Ultra HD LCD or OLED television, there's a lot that goes on behind the scenes to display an image correctly and at the highest quality possible. All TVs might seem (very roughly) equal when you see them in the store, but there's a lot of different aspects — 4K, LED, HDR and more — that you need to learn before you pick a new screen to buy. Here's our quick guide to all the important tech inside your TV.
Sony was first to market with both 4K UHD TV and Android TV in Australia. From the director’s lens to the living room, Sony is a proven leader of innovation and technology in home entertainment.
From Source To Screen: TV Image Processing
Any TV has a native resolution — the number of individual pixels that the LCD or OLED screen is built up of — but the content that any modern TV displays is only very rarely delivered in that native resolution. It took quite a while for Full HD Blu-ray video and 1080p streaming video to become ubiquitous after the launch of Full HD LCD and plasma TVs, for example. With the new wave of affordable and high quality 4K TVs quickly becoming available on store shelves, though, we're seeing that trend reversed — you can already buy Ultra HD Blu-rays with a 4K native resolution and with super-high bit-rates that don't require any extra image processing.
For any lower-resolution content, like 1080p or 720p streaming video, or even lower-resolution YouTube or broadcast TV on a 4K TV, your TV has to apply image processing to that source to bring it up to the resolution required for 4K display. A great, new 4K TV will have a powerful image processing chip that does a huge amount behind the scenes — upscaling video frames, interpolating extra pixels where needed, applying smart sharpening, and altering contrast — to bring lower-quality video up to standard. Generally, a more powerful imaging processor chip will allow for more complicated routines to run, and should translate into higher quality upscaled video.
Full HD And 4K: Screen Resolutions
In 2016, we're reaching a tipping point where many of the new televisions that are being launched onto electronics store shelves are 4K, rather than the 1080p Full HD resolution that has been the dominant standard since around 2010. Where a Full HD display has a native resolution — the number of individual dots or cells that the screen itself is made up of — of 1920 pixels horizontally and 1080 pixels vertically in each line, a 4K or Ultra HD display has 3840 pixels horizontally and 2160 pixels vertically. When you multiply each of these numbers to get the overall resolution in megapixels, Full HD's 2.1 megapixels of imaging information per frame pales in comparison to Ultra HD's 8.3 megapixels.
At four times the native resolution, Ultra HD has a big advantage in the amount of detail that it can display from a good quality source. Ultra HD TVs also up-scale lower quality content to their native resolution, and while it's not perfect — you can't add in missing data — it generally does a pretty good job. To get the most out of an Ultra HD TV, you need to be able to stream high quality video from the internet, with native 4K streaming only available through Netflix or YouTube in Australia at the moment, or to invest in a new Ultra HD-compatible Blu-ray player, more of which are starting to become available in Australia.
HDR: High Dynamic Range And Dolby Vision
High dynamic range is one of those technologies that has to be seen to be believed. Any modern TV — whether it's LED or OLED — has the ability to adjust the level of its backlight to display deep, dark, inky blacks and bright, clear, shining whites. Within the same display, both LED and OLED have the ability to adjust brightness on different sections of the screen simultaneously, displaying shadows alongside whites as best as possible. With anywhere upwards of 24 frames of video being displayed on a TV every second, though, the HDR standard ensures that your TV's backlight level is optimised for each segment of video, through metadata embedded in the video stream or Blu-ray disc you're watching.
Dolby Vision and HDR-10 are two examples of competing standards within the high dynamic range umbrella. HDR-10 is the more vanilla of the two, and is the mandatory specification for Ultra HD Blu-ray movies: if you want to watch a new 4K Ultra HD movie with HDR support, your TV has to at least support HDR-10. But Dolby Vision takes the technology standard to another level with the video production company adjusting colour and brightness levels on every single individual video frame, and ensuring each movie or TV show passes a rigorous in-house certification process. Having one is great, having both is even better, but at a minimum any new 4K TV you buy should also support HDR video out of the box.
LED Backlighting And Quantum Dots
LED backlighting is the current standard for LCD TVs, taking over from the old and inefficient cold-cathode fluorescent tubes used when LCD TVs were still new, but LED nonetheless has a couple of different approaches to how it operates. Edge-lit LED TVs (which use a strip of LEDs around the outer edge of a display) are more cost-effective and use slightly less power as the number of LEDs used is smaller, but a full back-lit array (a sheet of LEDs shining directly past the LCD) will technology provide better picture quality through more accurate application of local dimming.
A relatively new invention in the world of LED-backlit TVs, quantum dots are tiny — literally nanometre-scale — particles that, because they are so small, have unique optical properties. Quantum dots can extremely efficiently filter any light source to only emit red, blue or green light, which makes them fantastic for displaying accurate colour from a TV. Using blue LED backlighting rather than white or red-green-blue LEDs allows those blue LEDs to be more powerful and produce more light, which is then filtered by quantum dots. The effect is that a quantum dot display will have better outright colour performance than a non-quantum dot TV, but will come at an extra cost.