What is HLG Hybrid Log Gamma?

Hybrid Log Gamma (HLG) And What It’s Going To Do For You

Any customer currently in search of a modern TV is likely to be bombarded with various acronyms and three-letter tech abbreviations. We’ve had High Dynamic Range (HDR), 4K, Ultra High Definition (UHD) and now‚Ķ..Hybrid Log Gamma or HLG for short.

What is HLG Hybrid Log Gamma?

So What is it?

At the moment, the only way you can enjoy HDR content on your TV is via Netflix or Amazon, from an Ultra HD Blu-ray player or a SKY Q box.

The BBC (Another abbreviation) are looking to remedy that particular problem, by providing a way for HDR content to be broadcast live over the air.

A brief explanation of HDR

In case you’re not in the know, High Dynamic Range pertains to the contrast between the brightest whites and the darkest blacks produced on a TV screen. The distance between the very whitest white colours and the very darkest blacks is what is referred to as the dynamic ‘range’.

HLG is one of four HDR formats that also include Technicolor, HDR10 and Dolby.

How Did HLG Come About?

The answer to that question is an interesting one. Necessity is the mother of invention, as they say, and the need arose to create this technology as end-to-end metadata contained in conventional HDR content was too unreliable and vulnerable to interference to be considered a viable method.

Since 2014, the BBC has been collaborating with NHK, a public broadcaster from Japan to develop a system that allows HDR content to be broadcast live, over the air. A collaboration that has now seen HLG become reality.

How Can It Be Watched?

Interestingly, HLG has been devised in a way that means it doesn’t require an HDR TV to view it, but you will still require a 4K TV. Without getting too technical, HLG has been created as a system that uses scene referencing, just as traditional TV does already.

Backwards Compatible

4K TVs can have their dynamic range increased when using HLG, with the added benefit of it not being necessary to have HDR compatibility in your set i.e. non-HDR receivers can be used to view HLG HDR content.

Testing Phase

Whilst HLG is very close, it is still not quite in the launch phase, but is being tested heavily by a number of parties including NHK, the BBC and certain TV manufacturers. One thing is for sure however, it won’t be too long until we are all enjoying HLG HDR content both live on the BBC and via their iPlayer.

The end of 2016 saw a trial 4K UHD clip of David Attenborough’s ‘Planet Earth II’, which were only viewable using selected TVs. More trials are in the pipeline which should be available too many brands of TV including Sony & LG.

As to how successful it will be and the actual timescale involved, the proof is in the pudding.

For more information on HLG HDR or any of the myriad of acronyms and abbreviations in the home entertainment world, why not visit the rest of our technology blog.

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Matt Tomkin

I am an avid tech lover and the journey started back when LCD TVs and Plasma image burn were all too common. Over the years I have sold technology in retail stores but more recently have been building numerous businesses all based around technology. It's great to be able to test new tech and provide my thoughts on a platform like this.