High-definition Multimedia Interface (HDMI) is a video and audio connection used between HD equipment, such as a Blu-ray player, PVR or a Sky HD box, and your television.
Until the arrival of high definition (HD), the vast majority of connections were carried out using Scart leads. You can still use Scart leads to connect Blu ray players, games consoles and more devices, but you'll need to use HDMI leads to enjoy full HD picture quality.
Budget and small-screen TVs tend to only have a few HDMI sockets, but most large-screen TVs have three, four or maybe even five. More ports can be added to your TV using an HDMI switching box if you like.
Whatever price, type or brand you want, we've got you covered with our expert and independent TV reviews
Don't buy expensive HDMI cables
Retailers will be quick to promote expensive HDMI leads with fancy-sounding features, such as gold-plated connecting pins. Some may cost the same as a decent Blu-ray player. However, save your money and buy the cheapest leads available.
Which? testing has shown that cheap HDMI leads - even value ones costing just a few pounds - can perform just as well as more expensive ones. When we last ran HDMI tests, we found that a £10 HDMI lead from a supermarket gave no discernible difference in picture quality to one costing almost £100.
HDMI features explained
- HDMI ARC: Available on most TVs these days, HDMI Audio Return Channel (ARC) can be a great way to connect up a home cinema system, AV receiver or sound bar with less fuss. Basically, it allows you to just use one HDMI lead to send audio from your TV to your sound receiver. However, not all TVs support multi-channel audio via HDMI, and that means they won't support 5.1 surround sound, for example.
- HDMI CEC: Consumer Electronics Control (CEC) is a neat but often underused HDMI feature that enables you to control multiple different CEC-enabled devices, such as a TV, DVD player and set top box, that are connect via HDMI from the same remote control.
- MHL cables: Many modern TVs allow you to connect your smartphone or tablet using an MHL (Mobile High Definition Link) cable plugged in the phone and then connected via the TV's HDMI. This allows you to share content such as videos or photos on the larger screen, and it charges your device at the same time.
- HDMI 1.4: Most TVs now have HDMI 1.4 connectors as standard. These ports can support broadcast HD TV, as well as 3D Blu-rays played through a 3D TV. While you can use a HDMI 1.3 lead with these ports, the picture quality won't be as good as a HDMI 1.4 lead.
- HDMI 2.0: With the advent of 4K ultra-high-definition (UHD) TV, a new HDMI 2.0 standard was agreed. HDMI 2.0 brought various improvements, including support for 4K UHD resolution at 60 frames per second (measured in Hz) and the Rec. 2020 colour space. This as vital now that 4K UHD is more widely distributed to televisions.
- HDMI 2.1: The latest HDMI version supports resolutions up to 8K at 60Hz and 4K up to 120Hz. It's particularly useful for gaming since the Xbox Series X and PlayStation 5 are able to play games up to 120Hz. You don't need any new cables to take advantage of these features at the moment, but as people start buying more 8K TVs they may need a 48Gbps HDMI cable to more quickly transmit the large amount of data required for 8K content. This isn't such an issue now because 8K sets are scarce and not worth buying because there's very little 8K content to watch on them aside from some YouTube videos.
Take a look at our best TVs for gaming for more details on why HDMI 2.1 is a feature worth having on your next TV.