Top 10 features your next TV must have
These are the features you should be looking for if you want your new TV to be future-proof
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79For some it's once a decade and for others it's an annual event but sooner or later you end up buying a new TV.Until recently that's been a fairly straightforward affair - you decide on your budget and what screen size best suits your room and then read the reviews on AVForums before heading down to your local store to take a look for yourself. After demoing your short list you decide which TV you like the best and part with your hard-earned cash. However we are currently going through the biggest changes in the TV industry in a generation with not only an increase in resolution but new standards that will take television to the next level. If that wasn't enough the introduction of smart technologies and video streaming are even changing the very way that we watch TV.
At first you might think that the advent of 4K Ultra HD is similar to the introduction of high definition over ten years ago but it goes much further than that because the current changes aren't just about another increase in resolution. When high definition arrived it increased the resolution noticeably but in most other respects the standards remained the same as they had for decades. The new high definition panels were still using 8-bit video depth and the Rec.709 colour space, whilst the standard dynamic range was based on the limitations of the old CRT (cathode ray tube) technology. The reason for this was that at the time the professional mastering suites were still using CRT monitors and that legacy has remained until now.
The consumer electronics industry has realised that the additional resolution offered by 4K Ultra HD isn't enough to tempt people to upgrade their high definition TVs and as such they are also changing the standards associated with TV. The result will be a set of new standards that allow filmmakers to realise all the detail that is inherent in the original content and allow modern TVs to take full advantage of their innate technological potential. In fact if you don't need to buy a TV right now, the best option would be to wait until all the standards have been finalised and then take the plunge. However if you're determined to pick up a new set then this guide will take you through the features that will make sure it's suitably future-proof.
1. 4K Ultra HD Resolution
This may seem rather obvious but clearly the first thing that your new TV will need is a 4K panel with a resolution of 3840 x 2160 pixels. This is the agreed Ultra High Definition resolution for domestic televisions and will be used for 4K content delivered by Blu-ray, streaming services and broadcast. The reality is that by next year you'll probably find it hard to actually buy a high definition TV with a 1920 x 1080 pixel resolution and those that are available will be in smaller screen sizes. The larger the screen size, the more consumers will benefit from the increased resolution of Ultra HD, so the manufacturers will obviously concentrate on the bigger models as part of their drive to push UHD. The average screen size in the UK has been gradually increasing over the last few years as the quality and resolution of our TV images improves. Our advice would be to always choose the largest screen size that you can comfortably fit in your viewing environment. You won't believe how many times we hear someone say "I wish I'd gone for the larger screen size." The good news is that the prices of Ultra HD TVs are falling fast and even if you're on a budget, you should be able to find a decent sized panel.
2. HDR Support
In the introduction we mentioned that the consumer electronics industry realised just increasing the resolution wouldn't be enough to tempt people into upgrading their high definition TVs. So a number of other features are also being introduced along with 4K Ultra HD to give the increased resolution greater impact. One of the most important features is High Dynamic Range (HDR) which will extend the dynamic range (difference between black and white) of images by making the blacks deeper and the highlights brighter. It will also allow content mastered in HDR to deliver more detail in the shadows as well as in the brighter parts of the image, even within the same frame. Amongst industry insiders HDR is considered something of a game changer and although only the flagship TVs released this year currently support HDR, we can expect to see the technology filter down to other models next year.
Streaming services like Amazon Instant and Netflix are already offering content in HDR and it is included in the specifications of the upcoming 4K Ultra HD Blu-ray format. There are also tests being conducted by broadcasters like the BBC, so we can expect to see plenty of HDR content going forward. So you definitely want to make sure that your next TV supports HDR, although of course it isn't quite that simple because there are a number of different HDR systems in contention. The industry is trying to create a single HDR workflow and ecosystem, which will hopefully eliminate incompatibility and consumer confusion, but nothing has been agreed yet. There will also be the mapping technology available which will map the HDR content to the capabilities of the TV itself and you can find out more about high dynamic range here.
3. Wider Colour Space
The current colour space used in all high definition TV broadcast and Blu-ray disc mastering is Rec.709 and although this standard has served the industry well for decades, modern TVs are capable of a wider colour performance. Of course this doesn't mean you should boost the colour control on your TV just because its native colour space is wider than Rec.709. It's important that your TV matches the industry standard being used so that what you're seeing is what the content creator's want you to see. If you take a look at the last feature on this list you can find out more about image accuracy.
However the advent of new industry standards means that going forward 4K Ultra HD content will be mastered using a wider colour space. The proposed standard actually goes as high as Rec.2020 which is a massive colour space that isn't currently supported by anyone, so it's unlikely that will actually be used any time soon. However in the cinema they use a wider colour space called DCI and since films are already mastered using this colour space it would seem logical to assume that's what will be adopted for domestic use. In the graph above, the smallest triangle is Rec.709, the next is DCI and the largest is Rec.2020 - so you can see there is quite a difference. And in case you were wondering, D65 is the industry standard for the colour of white.
This year has seen the introduction of Quantum Dot technology which has allowed manufacturers to increase the size of the native colour space on their TVs considerably. We have yet to actually test a TV that can fully reach DCI but TVs released recently have managed 92 to 98%, so we're getting close. We would expect TVs next year to be able to hit 100% of DCI and as always we will measure the native colour space in our reviews to ensure this is the case. What this basically means is that your next TV should have as wide a colour space as possible and ideally hit DCI. However if your TV can't reach 100% of DCI don't worry because thanks to tone mapping the colour space used in the content will be mapped to the native colour space of your TV, so you should still be able to enjoy the benefits of an increased colour palette.
4. 10-bit Panel
When people talk about colour depth or bit depth what they're referring to is the number of bits used for each colour component of a single pixel. So the higher the number the greater the level of colour accuracy in terms of the shades of each of the primary colours (red, green and blue). Until recently the standard colour depth has been 8-bit and that has been used for all the standard and HD content that we watch. So naturally all the TV panels produced until recently were 8-bit panels to match that standard. A colour depth of 8-bit means that there are 256 shades per a primary colour which equates to a total of 16.78 million different colours. That might seem like a lot but just increasing the colour depth to 10-bit means 1,024 shades of each primary colour and a total of 1.07 billion colours!
The introduction of the HEVC codec (see below) allows for either 8- or 10-bit accuracy and the standards being adopted for 4K Ultra HD will use a 10-bit colour depth. The application of a higher bit depth is really essential for the best implementation of HDR and a wider colour space, so this year we have seen more and more TVs using 10-bit panels. Although manufacturers don't always make it clear whether their TVs are using 8- or 10-bit panels, we always check this in our reviews. Therefore in order to take advantage of the full potential of HDR and a wider colour space, as well as enjoy the greater detail afforded by increased colour depth, which can eliminate issues like banding in blocks of colour, your next TV should use a 10-bit panel.
5. HDMI 2.0a Inputs
There are so many different types of HDMI input these days that it can get quite confusing. Until recently the main type of HDMI input being used was version 1.4, the final version of which (1.4b) was introduced in 2011. This version added support for ARC (Audio Return Channel), HEC (HDMI Ethernet Channel) and 3D up to 120Hz. It also increased the maximum resolution to 4K Ultra HD (3840 x 2160) at up to 24/25/30Hz. This meant that early Ultra HD TVs could handle 4K content whilst only using version 1.4b HDMI inputs but this approach had its limitations. Whilst a 4K movie would only need 24Hz, any 4K broadcaster would be using a higher frame rate, either 50 or 60Hz depending on the country. BT Sport's Ultra HD Channel uses 50Hz for example, so to take advantage of these upcoming services a new version of HDMI was required.
The majority of Ultra HD TVs now use HDMI 2.0 which, along with support for 4K frame rates up to 60Hz also adds the Rec.2020 colour space. So if your TV has HDMI 2.0 it can take advantage of all the new features that 4K Ultra HD Blu-ray has to offer - right? Well not quite because UHD Blu-ray (and ultimately UHD broadcasters like BT Sport) includes support for HDR and that requires additional metadata. For this metadata to be sent via HDMI you will need version 2.0a which was released in 2015. That means if you want your new Ultra HD TV to be able to take full advantage of all the upcoming 4K sources you need to make sure it uses HDMI 2.0a inputs. As is often the case, manufacturers don't always make it clear exactly which type of HDMI input they are using on their TVs but wherever possible we identify the type of HDMI input in our reviews.
6. HDCP 2.2 Support
HDCP stands for High-bandwidth Digital Content Protection and is a form of copy protection that was originally developed by Intel to prevent digital audio and video content from being copied as it moves between connected devices. HDCP is used as copy protection on a number of different connection types including DisplayPort, DVI and HDMI. The system is meant to stop HDCP-encrypted content from being played on unauthorised devices or devices which have been modified to copy HDCP content. Before sending data, a transmitting device checks that the receiver is authorised to receive it. If so, the transmitter encrypts the data to prevent it being copied as it goes to the receiver. The latest iteration of HDCP is version 2.2, which is being rolled out to new 4K devices such as Ultra HD Blu-ray to ensure that 4K content is copy protected. The adoption of HDCP 2.2 has been ongoing for some time and the majority of TVs we have reviewed this year have included the latest version on at least one HDMI input. However it's important that you make sure your new TV supports HDCP 2.2 because if it doesn't it wouldn't be able to receive content from devices that use copy protection.
7. HEVC Decoding
HEVC stands for High Efficiency Video Coding and is the new video compression standard that has been developed primarily for delivering 4K, either via streaming or on Blu-ray. By using HEVC coding more information can be compressed more efficiently, allowing 4K content to fit onto a Blu-ray or be streamed over a broadband connection. In the case of 4K Ultra HD Blu-ray the HEVC decoding is done in the player which then outputs the content via HDMI 2.0a with HDCP 2.2, which is why your new TV will need both those features. However if you want your new TV to take advantage of the latest 4K streaming services, then built-in HEVC decoding will be essential. Since 4K delivery over the internet will be one of the only ways to access content for a while, you definitely want your new TV to include HEVC decoding.
8. 4K Streaming Services
At the moment, the only way to access 4K content is through streaming services like Amazon Instant and Netflix. In fact the streaming services have largely been leading the way as far as Ultra HD delivery is concerned, producing their own content in 4K and pioneering HDR and wider colour spaces. They also use HEVC encoding, which is another reason why you want to make sure your TV can decode that particular codec. Assuming that you have a fast enough broadband connection, Amazon and Netflix are currently your best bet for native 4K content, so make sure your new TV supports the 4K version of both streaming services. Whilst Amazon and Netflix have been grabbing a lot of the headlines recently, don't forget that YouTube also offers 4K content, although to take advantage of that you'll need to make sure your TV can also decode the VP9 codec as well.
9. Smart TV
If there is one area that has fundamentally changed the nature of television, regardless of the resolution of the panel, it's the advent of Smart TV. Whilst it was rather clunky and disappointing in its early days, the Smart TV platforms on the latest TVs are beginning to fully exploit the potential of a connected digital hub. The more processing power that a TV can pack under its hood, the smarter the features it can offer and the faster it can perform, so look out for TVs with at least quad-core processing, although many now have hexa-core or octa-core processing these days. All the major TV manufacturers now use dedicated operating systems with LG's based around webOS, Samsung's powered by Tizen, Panasonic's using Firefox and Sony and Philips adopting Android TV.
Probably the most important aspect of any smart platform is the number of catch-up and streaming services it offers - the more the better. Another useful feature is built-in WiFi and networking capabilities, allowing you to stream content from other devices and access your home network. There are also opportunities to indulge in a spot of social networking or even make Skype video calls, either with a built-in camera or an attachment. Yes the Smart TV platform has come a long way from the days of a web browser and BBC iPlayer, so these days you should be expecting a sophisticated operating system, with hundreds of apps at your disposal. Which smart platform is best for you is really a matter of personal preference but make sure your new TV has the necessary smarts.
10. Out-of-the-Box Accuracy
Of course there isn't much point having all these cutting edge features if the picture doesn't look very good. Whilst the majority of TVs these days actually come with some surprisingly effective calibration controls, the reality is that most people aren't going to get a professional calibration. So the out-of-the-box accuracy is important and, if you follow some simple steps, most TVs are capable of a reasonable performance without resorting to a calibration. When we review a TV here at AVForums we always measure the out-of-the-box accuracy, along with the calibrated performance, to help readers decide which TV best suits them. If you don't plan on getting your new TV calibrated, which is probably likely, then it's important that it can deliver an accurate picture with the minimum of setup. If you want to find out how to get the best picture from your new TV, take a look at our PicturePerfect page here.
So there you have it, the ten features that your new TV must have if it's to stay relevant and cutting edge over the next few years. At the moment all of these features are only found on the higher-end TVs and flagship models, so if you want the best you'll have to pay for it. However even if you're on a budget don't panic because many of these features have already filtered down to cheaper models and we can expect the majority of 4K Ultra HD TVs to support these features over the next two years. Whether you knew it or not, a brave new world of Ultra High Definition television is just around the corner.
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