HDMI (High-Definition Multimedia Interface) cables connect video source components like set-top boxes, game consoles and streaming devices to TV screens and A/V receivers. HDMI standards have evolved over time and some earlier cables do not have the bandwidth to carry a 4K video signal or the ability to transmit HDR data. If you have the wrong cables, the 4K HDR content coming from your video source will not be passed on to your TV screen.
HDMI cable labeling is a lot more confusing than it needs to be and some cable manufacturers take advantage of this confusion to sell overpriced cables to unsuspecting customers. The good news is that in most cases the HDMI cables people are currently using are capable of carrying a 4K HDR video signal. The bad news is that it can be difficult to be certain whether or not a particular cable is adequate to the task. Here’s what you need to know to make sure you have the right cables in place when you upgrade to 4K HDR.
There are four certification standards for HDMI cables that pertain to home use. Cables that are certified as Standard are "tested to reliably transmit 1080i or 720p video". There are two varieties of Standard cables, those with an ethernet channel and those without. High-Speed HDMI cables are tested to transmit video resolutions from 1080p to 4K along with a richer color palette. High-Speed HDMI cables also come in ethernet and non-ethernet versions. If you want 4K resolution with or without HDR, you need High-Speed HDMI cables.
There is also a Premium High-Speed HDMI certification for ethernet and non-ethernet cables. Cables with a premium certification go through more rigorous testing and are certified for high reliability 4K performance, high bandwidth, HDR and an expanded color palette. Premium certification is optional.
There are also different versions of the certification standards that have changed over time. HDMI first appeared on the scene 15 years ago. The first version of HDMI that was classified as High Speed was version 1.4 which was released in 2009. In addition to 4K resolution, version 1.4 added ethernet connectivity, an audio return channel (ARC, which can be useful depending on how your system is set up), and 3D capability. Most cables purchased after 2009 are High Speed and will pass a 4K signal to your screen.
Version 2.0 was released in September 2013. The major differences from 1.4 are testing for a marked increase in bandwidth and the ability to present a wider variety of colors. Version 2.0 is certified to have a bandwidth of 18 Gigabits per second which is sufficient for 4K resolution at 60 fps (frames per second).
Most 4K video runs at 24 or 30 fps but a 60 fps frame rate is becoming increasingly popular. YouTube began hosting 4K 60 fps videos last year and Netflix may not transmit 4K HDR content if it determines that your video system cannot handle a 60 fps frame rate. Sixty fps is especially important for gamers who are playing in 4K. Microsoft’s recently unveiled Xbox One X which launches on November 7 sets 4K 60 fps as its standard.
Two versions of 2.0 have been released since 2013. Version 2.0a was released in April 2015, and 2.0b was released in March 2016). Both specify tests for different types of HDR. Screens with HDR increase brightness and display more colors than screens without. With HDR, colors are rich and vibrant, and the range of colors shown on the screen is closer to the range the human eye can see. The difference is very noticeable and very pleasing.
HDMI has always been a forwarding-thinking technology. HDMA 2.1 is scheduled to be released this summer. It ennables dynamic HDR along with faster refresh rates and much higher bandwidths. It also demands a different type of cable which has a working name of "48G Cable". At present, no content needs HDMI 2.1.
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