HDMI – because you are going to need to know

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If you don’t know the difference between HDMI 1.4 and 2.0 or 2.1, then read on because it is the difference between buying a TV for today and one for the future. We also discuss HDMI cable types and why they are so important.

We will stick to TVs, and soundbars/AV amps for now but HDMI (High-Definition Multimedia Interface) is the most common single cable audio/video interface between two devices.

Some soundbars have multiple HDMI inputs as well as an HDMI ARC output

HDMI devices include all TVs and most soundbars, Blu-ray/DVD players, PlayStation, Xbox, Set-top Box, PC/media centre, cameras and more. By TV we also mean a video projector, PC monitor or even a digital audio device.

First some definitions

  • HDMI ARC (Audio Return Channel) simply means that the HDMI cable works both ways for audio – for example, the soundbar can receive audio from the TV and vice versa.
  • HDMI eARC (enhanced ARC) is a new standard that means more features, faster speeds and higher quality video and audio. This is on newer and more expensive 2019+ TVs like Sony’s A9G OLED.
  • HDMI CEC (Consumer Electronics Control) means you can use the TV or soundbar IR or BT remote control to turn on/off both devices, volume, and some basic play features. Its also known as Sony Bravia Link or Sync, Samsung Anynet+, LG SimpLink and many more.
  • HDMI Audio is up to 8 channels (7.1) for HDMI 1.4, and 32 channels for HDMI 2.0/2.1. It has 16/20/24-bit, sample rates of 32/44.1/48/88.2/96/176.4/192 kHz or will passthrough (on some TVs) Dolby Atmos or other content to an Atmos soundbar for processing.
  • HDCP (High Bandwidth Digital Content Protection) protects Digital Rights of content makers via encryption – it is to prevent content copying.
  • HDR (High dynamic range) includes metadata in the video stream. HDR10, HDR10+ and Dolby Vision/IQ are supersets of HDR. HDR is static meaning that the TV only adjusts the picture once at the beginning. HDR10+ is dynamic and can adjust the picture on a scene-by-scene, and Dolby Vision/IQ can adjust frame-by-frame.
  • HLG (Hybrid Log-Gamma) is how TV stations will transmit 4K free-to-air TV.

HDMI standards

HDMI started in 2004. It quickly took over as a single cable solution and on all TVs.

All you need to know is that it has versions 1.0, 1.1, 1.2, 1.3a, 1.4, 1.4a, 1.4b, 2.0, 2.0a, 2.0b and now 2.1. HDMI devices and cables are backwards compatible to the extent that earlier versions simply do not support latter features.

We will focus on HDMI 1.4 to 2.1.

HDMI 1.4/a/b

This supports 10Gbps and 4K (4096×2160@24Hz, 3840×2169@24/25/30Hz) as well FHD (1920×1080@120Hz) or less. It also supports Ethernet (HEC), ARC, Adobe RGB, and 3D TV (although that really did not work well until 1.4b).

If you are buying a lower-cost 4K TV, then 1.4/a/b (that’s or a or b) is all you need for today. It will support everything you can connect to it, but you won’t get Dolby Vision or Atmos passthrough.


There are two types of HDMI 1.4 cables (both varieties can have Ethernet options as well).

Most low-cost cables are Category 1. No matter how good your 4K Blu-ray may be, you can’t get more than 1080p and 720p on your TV. These can be up to 13m, but in practice anything over 3-5 metres is dodgy. Do not buy Category 1 if you have 4K devices!

There are also Category 2 ‘high speed’ cables that support 4K and 3D. These can be up to 5-metres but are typically 2-metres.

But the catch 22 is that there are generally no markings on the cables so assume that these are all Category 1 and that means not suitable for connection of 4K devices to a TV or soundbar.

HDMI 2.0 – 4K@60Hz compatible

This ups the speed over HDMI to 18Gbps but needs Category 3 ‘Premium High Speed’ (optionally plus Ethernet). It supports Rec. 2020 colour gamut 24-bit colour, 32 audio channels, dual video streams, four audio streams, static HDR (HDR in 2.0a and HDR10 in 2.0b) and HLG (2.0b).

This is more than adequate for 4K TVs, Dolby Vision/Atmos and current devices.

No confusion on Laser’s Premium High Speed Cables – it even includes HDMI 2.0b identification

HDMI 2.1 – 4/5/8/10K@120Hz compatible (includes Ethernet)

This takes the speed to 48Gbps, and cables are 48G or ‘Ultra High Speed’. As cables are backwards but not forwards compatible you should buy HDMI 2.0 or 2.1 compatible if you can afford to.

This is relevant to 8K TVs, although as yet we have no consumer 8K content players apart from a Samsung Galaxy S20 Ultra smartphone that can record and playback 8K video.

It supports Dynamic HDR (scene-by-scene or even frame-by-frame), eARC (that also supports Dolby Atmos or DTS:X sound), faster screen refresh Hz, ALLM (Auto Low Latency Mode). Video over 8K is compressed (DSC).

You can read more about HDMI here.

Cable summary (prefixed by category/version)

  • 1 for 1080p only – throw these away if you have 4K. The cost is from a few dollars and are likely most of the HDMI cables you have lying around.
  • 2 High Speed for 4K@30Hz – if you want to play Blu-Ray Dolby Atmos content forget these. Cost $20-$50
  • 3 Premium High Speed for 4K@60Hz – supports Dolby Atmos and good all-rounder – the ones to buy. Cost $50-100.
  • 48G Ultra High Speed – mandatory for 8K and best of all are backwards compatible. Cost $100+

We spoke to Chris Lau, owner of Laser that makes a huge range of cables and accessories sold in most electronics and chain stores. He said:

“Most people don’t know that there are different categories of HDMI cables. They never know that the lower cost ones don’t support deep colour, HDR or many of HDMI’s latest feature like Dolby Atmos. We are yet to see a demand for HDMI 2.1 cables so for now buy Category 3 Premium High Speed if you have a 4K TV and Blu-ray player that supports Dolby Vision and Atmos.”

If a salesman pushes you to high-cost cables (often well over $100) it is usually an upsell as HDMI is a digital signal – it works, or it does not. And similarly, a lower-cost cable is all you need for runs under 3 metres – don’t fall for the salesman’s slick spiel – it is to earn them more money.

Laser has Category 3 Premium High-Speed HDMI cables in 2/3/5-metre lengths for $79.95/99.95/129.95

It will also shortly have Category 48G – its just undergoing final certification.

These <$30 cables from Amazon are about as dodgy as you can get with nothing other than the packaging as ‘proof’. Merchants know that you will never us it unless you have an 8K TV.