As one of many new content formats found in modern televisions, you may have support for Hybrid Log Gamma (or 'HLG') in your TV and not even know it. But what is HLG, and why should you care? The answer lies with HDR (High Dynamic Range): a video format that enhances the brightness, sharpness, and color gamut of an image beyond SDR (Standard Dynamic Range). What is HDR TV? Read more in our comprehensive guide to the television formatHDR already comes in several different guises, from the original HDR10 standard to the more exclusive Dolby Vision, the still-nascent Advanced HDR by Technicolor and, for broadcasters, Hybrid Log Gamma. To help you make sense of this brave new world of color and clarity, we\u2019ve put together a general overview of Hybrid Log Gamma\u2019s new HDR format and everything that makes it stand out from competing standards. So what is Hybrid Log Gamma? Hybrid Log Gamma (or HLG) is an HDR format developed by the UK's own BBC, in conjunction with NHK, Japan's national broadcaster. The issue traditional broadcasters have is that many of their viewers still hold on to old SDR television sets, which can't display the increasingly prevalent HDR standard. SDR is also much cheaper to film in, and the likes of the BBC are naturally reluctant to ditch a cost-effective format that tens of thousands of viewers still rely on. The HLG format works around this obstacle by coding both SDR and HDR footage into the same broadcasting signal. It's a far more efficient process for broadcasters, who then don't have to provide twice the amount of bandwidth to transmit their programming across the country in two separate formats. When reaching your home television, the HLG signal will display in HDR if your television is compatible with the HLG HDR format. Otherwise, it displays in regular ol\u2019 SDR \u2013 with some neat upscaling to bring it closer to its HDR counterpart. The HLG broadcast format is slightly different to HLG Photo Mode, which displays still HDR images from Panasonic Lumix cameras, and is exclusively available on OLED TVs in the 2019 Panasonic TV range. How does Hybrid Log Gamma work? Hybrid Log Gamma uses what\u2019s called an \u2018opto-optical transfer function\u2019 (sorry), which is the process used to convert a broadcast signal into the light that shows on your television screen. SDR and HDR footage are both converted into two types of light coding, which can then be unpacked separately depending on the compatibility of the television. The \u2018hybrid\u2019 in Hybrid Log Gamma refers to this dual-coding of SDR and HDR. \u2018Gamma\u2019 refers to the low-light image data encoded in the signal, while \u2018log\u2019 is short for the \u2018logarithmic curve\u2019 that transmits in HDR\u2019s wider brightness range. And why does anyone need Hybrid Log Gamma? While having a single dominant format would no doubt be simpler \u2013 for users who just want to get on with, you know, watching the telly \u2013 the competition is no doubt driving up the standard picture quality we expect from our television screens. HLG is only one of numerous HDR formats out there, which are all doing different things and are suited to different purposes. HDR10 is the most common out of these, and is usually what people refer to when they say 'HDR' (any HDR TV will come with it built in). Like HLG, it's an open-source format, meaning that anyone can use it, and it delivers on a wider color palette than SDR, with 10-bit color depth and a peak brightness of 4,000 nits . Dolby Vision is a well-regarded alternative, that can reach up to 10,000 nits brightness and a 12-bit color depth, and generally offers a better picture. It does, however, require royalties from content providers to use, and is therefore much less ubiquitous \u2013 and is already facing off competition from an upgraded HDR10+ standard with equivalent bells and whistles.\u00a0 Both Dolby Vision and HDR10+ use a type of \u2018dynamic metadata\u2019 in real-time, optimizing brightness and contrast to suit the images being shown onscreen in each shot. HLG is specifically made for the ease of broadcasters, meaning it forgoes metadata that could get lost or out of sync during a live broadcast. So what can I watch HLG content on? As with any new format, HLG will only be as strong as the players who support it. It\u2019s very much its own HDR format, and therefore an HDR TV will need to have the ability to recognise and play the format. Any recent HDR television from LG, Sony or Samsung \u2013 made in 2016 or after \u2013 have included HLG compatibility in firmware updates. Panasonic has also supported the format in a number of its premium HDR sets. There\u2019s scattered support elsewhere, including in the odd projector from Sony and JVC, but it\u2019s not as prevalent as HDR10 and you\u2019ll need to make sure it\u2019s supported in your specific make of television or otherwise. What's next for Hybrid Log Gamma? The BBC started trialing the technology in 2017 and \u2013 after some strong audience responses \u2013 has been rolling it out to flagship programmes like Blue Planet II, as well as major sporting events like this year\u2019s FIFA World Cup. One of the BBC\u2019s blog post on HLG reads: \u201cThe audience feedback from last year\u2019s trial was fantastic, and exceeded our expectations. Even with only those four minutes of content, we were delighted to learn that there is a real audience appetite for better quality pictures, and more of them.\u201d HLG is supported on BBC iPlayer \u2013 obviously \u2013 as well as YouTube, Freeview Play, and DirecTV. Hybrid Log Gamma will no doubt start appearing on more televisions, content platforms and the like, though in a heavily competitive market you never know what's going to last, and what will fall by the wayside.