View source for Hybrid log–gamma

{{Short description|High dynamic range standard that was jointly developed by the BBC and NHK}}
The '''hybrid log–gamma''' ('''HLG''') transfer function is a [[Transfer functions in imaging|transfer function]] jointly developed by the [[BBC]] and [[NHK]] for [[high dynamic range]] (HDR) display.<ref name="IBCDemo2015EBU">{{cite news |title=High Dynamic Range |publisher=[[European Broadcasting Union]] |url=https://tech.ebu.ch/docs/events/IBC2015/IBC_Fact_Sheet_HDR_Demo_Final.pdf |accessdate=2015-11-01}}</ref> It is backward compatible with the transfer function of SDR (the [[gamma curve]]).<ref name="HDRwithHLG2015BBC2">{{cite news|title=High Dynamic Range with Hybrid Log–Gamma|publisher=[[BBC]]|url=https://custom.cvent.com/63DDE0970BB04F3EA62737749B39B60C/files/event/841C5F30AA5948D4B4D985BC90AE0B2C/426e265101984437b7f9bde81acf8364.pdf|url-status=live|access-date=8 November 2015|archive-url=https://web.archive.org/web/20181109141347/https://custom.cvent.com/63DDE0970BB04F3EA62737749B39B60C/files/event/841C5F30AA5948D4B4D985BC90AE0B2C/426e265101984437b7f9bde81acf8364.pdf|archive-date=9 November 2018}}</ref> It was approved as '''ARIB STD-B67''' by the [[Association of Radio Industries and Businesses]] (ARIB).<ref name="IBCDemo2015EBU" /><ref name="HDRwithHLG2015BBC">{{cite news|title=High Dynamic Range with Hybrid Log–Gamma|publisher=[[BBC]]|url=https://custom.cvent.com/63DDE0970BB04F3EA62737749B39B60C/files/event/841C5F30AA5948D4B4D985BC90AE0B2C/426e265101984437b7f9bde81acf8364.pdf|accessdate=2015-11-08}}</ref><ref name="STDB672015ARIB">{{cite news|date=2015-07-03|title=ARIB STD-B67|publisher=[[Association of Radio Industries and Businesses]]|url=http://www.arib.or.jp/english/html/overview/doc/2-STD-B67v1_0.pdf|accessdate=2015-11-01}}</ref> It is also defined in [[ATSC 3.0]], [[Digital Video Broadcasting]] (DVB) [[Ultra-high-definition television|UHD]]-1 Phase 2, and [[International Telecommunication Union]] (ITU) [[Rec. 2100]].<ref name="Recommendation2100">{{cite news|date=2016-07-04|title=BT.2100 : Image parameter values for high dynamic range television for use in production and international programme exchange|publisher=International Telecommunication Union|url=http://www.itu.int/rec/R-REC-BT.2100-0-201607-I/en|accessdate=2016-07-04}}</ref><ref name="DVBUHDPhaseHDRNovember2016News">{{cite news|date=2016-11-17|title=DVB SB Approves UHD HDR Specification|publisher=[[Digital Video Broadcasting]]|url=https://www.dvb.org/news/uhd_1-phase-2-approved-by-dvb|accessdate=2017-01-07}}</ref><ref name="ATSC3VideoMay2017">{{cite news|date=2017-05-19|title=ATSC Standard: Video|publisher=Advanced Television Systems Committee|url=http://atsc.org/wp-content/uploads/2017/05/A341-2017-Video-HEVC.pdf|accessdate=2017-05-19}}</ref>

[[File:Hybrid Log-Gamma.svg|320px|right|thumb|Chart showing a conventional SDR gamma curve and the hybrid log–gamma curve. HLG uses a logarithmic curve for the upper half of the signal values, which allows for a larger dynamic range.]]

HLG is an [[HDR formats (for displays)|HDR format]] that uses the HLG transfer function, [[BT.2020]] [[Primary color|color primaries]] and a [[Color depth|bitdepth]] of 10-bit.<ref name=":42">{{cite web|date=19 October 2020|title=Ultra HD Forum Guidelines v2.4|url=https://ultrahdforum.org/wp-content/uploads/UHD-Guidelines-V2.4-Fall2020-1.pdf|publisher=Ultra HD Forum}}</ref> HLG was designed to be [[backward compatible]] with [[Standard-dynamic-range video|SDR]] [[Ultra-high-definition television|UHDTV]]. However, HLG is not intended to be fully backward compatible with traditional SDR displays that cannot interpret BT.2020 colorimetry.<ref name=":42" /><ref name=":0">{{Cite web|title=ITU-R Report BT.2390 - High dynamic range television for production and international programme exchange|url=https://www.itu.int/pub/R-REP-BT.2390|access-date=2021-09-11|website=ITU|language=en-US}}</ref>

Both HLG transfer function and the HLG format are [[royalty-free]].<ref name="HDRwithHLG2015BBC2" /> The backward compatibility allows them to be used with existing transmission standards when the receiver is compatible with the BT.2020 colour container, reducing complexity and cost for both equipment manufacturers and content distributors.<ref name="IBCDemo2015EBU" /><ref>{{Cite web|date=2019-12-23|title=All you wanted to know about Hybrid Log Gamma (HLG)|url=https://tmbroadcast.com/index.php/all-you-wanted-to-know-about-hybrid-log-gamma-hlg/|access-date=2020-05-27|website=TM Broadcast International|language=en-US}}</ref><ref name=":0" /> They are supported by [[HDMI]] 2.0b, [[High Efficiency Video Coding|HEVC]], [[VP9]], and [[H.264/MPEG-4 AVC]],<ref name="HDMI20bIntroduction">{{cite news|title=Introducing HDMI 2.0b|publisher=HDMI.org|url=http://www.hdmi.org/manufacturer/hdmi_2_0/index.aspx|accessdate=2017-01-07|archive-date=2016-12-03|archive-url=https://web.archive.org/web/20161203212800/http://www.hdmi.org/manufacturer/hdmi_2_0/index.aspx|url-status=dead}}</ref><ref name="HEVCJune2015U1005">{{cite news|author=Rajan Joshi|author2=Shan Liu|author3=Gary Sullivan|author4=Gerhard Tech|author5=Jizheng Xu|author6=Yan Ye|date=2015-09-05|title=HEVC Screen Content Coding Draft Text 4|publisher=JCT-VC|url=http://phenix.it-sudparis.eu/jct/doc_end_user/current_document.php?id=10214|accessdate=2015-11-01}}</ref><ref name="AndroidHDRSeptember2016Android">{{cite news|title=HDR Video Playback|publisher=Android|url=https://source.android.com/devices/tech/display/hdr.html|accessdate=2016-09-23}}</ref><ref name="AVC13April2017ITURecommendations">{{cite news|date=2017-04-13|title=ITU-T Recommendation H.264 (04/2017)|publisher=ITU|url=https://www.itu.int/ITU-T/recommendations/rec.aspx?rec=13189|accessdate=2017-06-14}}</ref>  and are used by video services such as [[BBC iPlayer]], [[DirecTV]], [[Freeview Play]], and [[YouTube]].<ref name="GoogleUploadHDRNovember2016Google">{{cite news|title=Upload High Dynamic Range (HDR) videos|publisher=Google Inc.|url=https://support.google.com/youtube/answer/7126552|accessdate=2017-01-11}}</ref><ref name="FreviewPlaySeptember2016Broadband">{{cite news|author=Julian Clover|date=2016-09-23|title=Freeview updates for HEVC and Ultra HD|publisher=Broadband TV News|url=http://www.broadbandtvnews.com/2016/09/23/freeview-updates-hevc-ultra-hd/|accessdate=2016-09-23}}</ref><ref name="BluePlanetHDRDecember2017BBC">{{cite news|author=Leo Kelion|date=2017-12-05|title=Blue Planet II comes to iPlayer in 4K HDR|publisher=BBC|url=https://www.bbc.com/news/technology-42225220|accessdate=2017-12-05}}</ref><ref name="DirectvHLGDecember2017Sportsvideo">{{cite news|author=Jason Dachman|date=2017-12-14|title=AT&T DirecTV To Deliver First Live 4K HDR Telecast in U.S. With Tonight's Penguins-Golden Knights Game|publisher=Sportsvideo|url=https://www.sportsvideo.org/2017/12/14/att-directv-to-deliver-first-live-4k-hdr-telecast-in-u-s-with-tonights-penguins-golden-knights-game/|accessdate=2018-01-10}}</ref><ref name="DirectvHLGDecember2017HDGuru">{{cite news|author=Greg Tarr|date=2017-12-15|title=DirecTV Presents NHL 4K Game With Live HDR, But Was Anyone Watching?|publisher=HDGuru|url=https://hdguru.com/directv-presents-nhl-4k-game-with-live-hdr-but-was-anyone-watching/|accessdate=2018-01-10}}</ref>

== Description ==
HLG is designed to be better-suited for [[television broadcasting]], where the metadata required for other HDR formats is not [[Backward compatibility|backward compatible]] with non-HDR displays, consumes additional [[Bandwidth (computing)|bandwidth]], and may also become out-of-sync or damaged in transmission. HLG defines a non-linear [[Opto-electronic transfer function|optical-electro transfer function]], in which the lower half of the signal values use a [[Gamma correction|gamma curve]] and the upper half of the signal values use a [[Logarithmic growth|logarithmic curve]].<ref name="DisplayHDR2015BBC2">{{cite news|author=T. Borer|first=|author2=A. Cotton|date=|title=A "Display Independent" High Dynamic Range Television System|work=|publisher=[[BBC]]|url=https://downloads.bbc.co.uk/rd/pubs/whp/whp-pdf-files/WHP309.pdf|url-status=live|access-date=1 November 2015|archive-url=https://web.archive.org/web/20160207193353/https://downloads.bbc.co.uk/rd/pubs/whp/whp-pdf-files/WHP309.pdf|archive-date=7 February 2016}}</ref><ref>{{Cite web |last= |first= |date=3 July 2015 |title=ARIB STD-B67 |url=http://www.arib.or.jp/english/html/overview/doc/2-STD-B67v1_0.pdf |url-status=live |archive-url=https://web.archive.org/web/20170329122104/http://www.arib.or.jp/english/html/overview/doc/2-STD-B67v1_0.pdf |archive-date=29 March 2017 |access-date=8 August 2017}}</ref> In practice, the signal is interpreted as normal by [[Standard-dynamic-range video|standard-dynamic-range]] displays (albeit capable of displaying more detail in highlights), but HLG-compatible displays can correctly interpret the logarithmic portion of the signal curve to provide a wider dynamic range.<ref name=":3">{{Cite web|last=Morrison|first=Geoffrey|title=What is HLG? Hybrid log gamma. Say what?|url=https://www.cnet.com/news/all-about-hlg-what-hybrid-log-gamma-means-for-your-tv/|url-status=live|archive-url=https://web.archive.org/web/20191007204408/https://www.cnet.com/news/all-about-hlg-what-hybrid-log-gamma-means-for-your-tv/|archive-date=7 October 2019|access-date=7 October 2019|website=CNET|language=en}}</ref><ref name=":4">{{Cite web|last=St. Leger|first=Henry|title=Hybrid Log Gamma: everything you need to know about HLG HDR|url=https://www.techradar.com/news/hybrid-log-gamma-what-you-need-to-know-about-hlg|url-status=live|archive-url=https://web.archive.org/web/20191007184226/https://www.techradar.com/news/hybrid-log-gamma-what-you-need-to-know-about-hlg|archive-date=7 October 2019|access-date=7 October 2019|website=TechRadar|language=en}}</ref><ref name=":5">{{Cite web|title=High Dynamic Range Television and Hybrid Log–Gamma|url=https://www.bbc.co.uk/rd/projects/high-dynamic-range|url-status=live|archive-url=https://web.archive.org/web/20191007185732/https://www.bbc.co.uk/rd/projects/high-dynamic-range|archive-date=7 October 2019|access-date=7 October 2019|website=BBC R&D}}</ref> In contrast with the other HDR formats it does not use metadata.<ref name="HDR TV: What it is and why your next TV should have it">{{cite web|author1=Michael Bizzaco|author2=Ryan Waniata|author3=Simon Cohen|date=19 December 2020|title=HDR TV: What it is and why your next TV should have it|url=https://www.digitaltrends.com/home-theater/what-is-hdr-tv/|url-status=live|archive-url=https://web.archive.org/web/20201221081838/https://www.digitaltrends.com/home-theater/what-is-hdr-tv/|archive-date=21 December 2020|access-date=2 January 2021|website=[[Digital Trends]]|publisher=Designtechnica Corporation}}</ref>

The HLG [[Transfer functions in imaging|transfer function]] is backward compatible with [[Standard-dynamic-range video|SDR]]'s [[Gamma correction|gamma curve]]. However, HLG is commonly used with [[Rec. 2020]] [[Primary color|color primaries]] which produce a de-[[Colorfulness|saturated]] image with visible [[hue]] shifts on non-compatible devices.<ref name=":422">{{Cite web|last=Ultra HD Forum|date=19 October 2020|title=Ultra HD Forum Guidelines v2.4|url=https://ultrahdforum.org/wp-content/uploads/UHD-Guidelines-V2.4-Fall2020-1.pdf|archive-url=|archive-date=|access-date=|website=}}</ref> HLG is therefore backward compatible with SDR-[[Ultra-high-definition television|UHDTV]] and will show color distortion on common SDR devices that only support [[Rec. 709]] color primaries.<ref name=":422" />

==Technical details==
HLG defines a [[Nonlinear system|nonlinear]] [[Transfer functions in imaging|transfer function]] in which the lower half of the signal values use a [[gamma correction|gamma curve]] and the upper half of the signal values use a [[logarithmic growth|logarithmic curve]].<ref name=STDB672015ARIB/><ref name=DisplayHDR2015BBC>{{cite news |title=A "Display Independent" High Dynamic Range Television System |author=T. Borer |author2=A. Cotton |publisher=[[BBC]] |url=http://downloads.bbc.co.uk/rd/pubs/whp/whp-pdf-files/WHP309.pdf |accessdate=2015-11-01}}</ref>

'''HLG reference OETF''' is as follows (as defined in ARIB STD-B67):

<math display="block">E'=\begin{cases}
r \, \sqrt{E}\ & 0 \le E \le 1,\!\\
a \ln(E - b) + c & 1 < E
\end{cases}
</math>

or as follows (as defined in [[Rec. 2100]]):<ref name="Recommendation2100" />

<math display="block">E'=\begin{cases}
\sqrt{3E}\ & 0 \le E \le \frac{1}{12} ,\!\\
a \ln(12E - b) + c & \frac{1}{12}  < E \le 1
\end{cases}
</math>

where

*''E'' is the linear light signal normalized by the [[reference white level]] in the range <math>\left[0, 12 \right]</math> in ARIB STD-B67 and in the range <math>\left[0, 1 \right]</math> in Rec. 2100.
*''E' '' is the resulting [[Nonlinear system|nonlinear]] signal
*''r'' is the reference white level and has a signal value of 0.5
* and the constants ''a'', ''b'', and ''c'' are defined as ''a'' = 0.17883277, ''b'' = 1 - 4''a'' = 0.28466892, and ''c'' = 0.5 - ''a'' ln(4''a'') = 0.55991073

The signal value is 0.5 for the reference white level while the signal value for 1 has a [[relative luminance]] that is 12 times higher than the reference white level.<ref name="DisplayHDR2015BBC" /> ARIB STD-B67 has a nominal range of 0 to 12.<ref name="HEVCFebruary2016W1005">{{cite news |title=HEVC Screen Content Coding Draft Text 6 |author=Rajan Joshi |author2=Shan Liu |author3=Gary Sullivan |author4=Gerhard Tech |author5=Ye-Kui Wang |author6=Jizheng Xu |author7=Yan Ye |publisher=JCT-VC |url=http://phenix.it-sudparis.eu/jct/doc_end_user/current_document.php?id=10481 |date=2016-03-24 |accessdate=2016-03-26}}</ref> HLG uses a logarithmic curve for the upper half of the signal values due to [[Weber's law]].<ref name="DisplayHDR2015BBC" />

'''HLG reference OOTF''' is as follows:<ref name="Recommendation2100" />

<math display="block">\begin{cases}
F_D = OOTF[E]= \alpha Y_S^{\gamma-1} E \!\\
R_D = \alpha Y_S^{\gamma-1} R_S \!\\
G_D = \alpha Y_S^{\gamma-1} G_S \!\\
B_D = \alpha Y_S^{\gamma-1} B_S \!\\
Y_S = 0.2627 R_S + 0.6780 G_S + 0.0593 B_S
\end{cases}
</math>where

* <math>F_D</math> is the luminance of a displayed linear component <math>R_D, G_D, B_D</math> in cd/m<sup>2</sup>.
* <math>E</math> is a signal for each colour component {Rs, Gs, Bs} proportional to scene linear light normalized to the range <math>\left[0, 1 \right]</math>.
* <math>Y_S</math> is the normalized linear scene luminance.
* <math>\alpha</math> is the variable for user gain in cd/m<sup>2</sup>. It represents LW, the nominal peak luminance of a display for achromatic pixels.
* <math>\gamma</math> is the system gamma. <math>\gamma</math> = 1.2 at the nominal display peak luminance of 1000&nbsp;cd/m<sup>2</sup>.

'''HLG reference EOTF''' is as follows:<ref name="Recommendation2100" />

<math>F_D = OOTF[OETF^{-1}[max(0,(1-\beta)E' + \beta )]]</math>

where

* <math>F_D</math> is the luminance of a displayed linear component <math>R_D, G_D, B_D</math> in cd/m<sup>2</sup>.
* <math>E'</math> is the non-linear electrical signal <math>R', G', B'</math> in the range <math>\left[0, 1 \right]</math>.
* <math>\beta = \sqrt{ 3 (L_B / L_W)^{1/\gamma} }</math> is the variable for user black level lift. 
* <math>L_W</math> is nominal peak luminance of the display in cd/m<sup>2</sup> for achromatic pixels. 
* <math>L_B</math> is the display luminance for black in cd/m<sup>2</sup>.

HLG does not need to use [[metadata]] since it is compatible with both [[Standard-dynamic-range video|SDR]] displays and [[High-dynamic-range video|HDR]] displays.<ref name="IBCDemo2015EBU" /><ref name="HDRwithHLG2015BBC" /> HLG can be used with displays of different [[brightness]] in a wide range of viewing environments.<ref name="HDRwithHLG2015BBC" />

The [[dynamic range]] that can be perceived by the [[human eye]] in a single image is around 14 [[Exposure value|stops]].<ref name=DisplayHDR2015BBC/> An [[Standard-dynamic-range video|SDR]] video display with a 2.4 [[Gamma correction|gamma curve]] and a [[color depth|bit depth]] of 8-bits per sample can display a range of about 6 stops without visible [[Colour banding|banding]].<ref name=DisplayHDR2015BBC/> Professional SDR video displays with a bit depth of 10-bits per sample extend that range to about 10 stops.<ref name=DisplayHDR2015BBC/> When HLG is displayed on a 2,000&nbsp;cd/m<sup>2</sup> display with a bit depth of 10-bits per sample it can display a range of 200,000:1 or 17.6 stops without visible banding.<ref name=DisplayHDR2015BBC/>

HLG increases the [[dynamic range]] of the video compared to a conventional gamma curve by using a logarithmic curve for the upper half of the signal values.<ref name=DisplayHDR2015BBC/> HLG also increases the dynamic range by not including the linear part of the conventional gamma curve used by [[Rec. 601]] and [[Rec. 709]].<ref name=ReportHDR2015SMPTE>{{cite news |title=Study Group Report High-Dynamic-Range (HDR) Imaging Ecosystem |publisher=Society of Motion Picture and Television Engineers |url=https://www.smpte.org/standards/reports |accessdate=2015-11-30}}</ref> The linear part of the conventional gamma curve was used to limit camera noise in low light video but is no longer needed with [[High-dynamic-range imaging|HDR cameras]].<ref name=ReportHDR2015SMPTE/>

HLG is supported in [[Rec. 2100]] with a nominal peak luminance of 1,000&nbsp;cd/m<sup>2</sup> and a system gamma value that can be adjusted depending on background luminance.<ref name=Recommendation2100/><ref name=ITUAnnouncesHDRJuly2016>{{cite news |title=ITU announces BT.2100 HDR TV standard |publisher=Rasmus Larsen |url=http://www.flatpanelshd.com/news.php?subaction=showfull&id=1467719709 |date=2016-07-05 |accessdate=2016-07-26}}</ref>

HLG is supported in [[High Efficiency Video Coding|HEVC]] with a formula that is mathematically equivalent to ARIB STD-B67 but has a nominal range of 0 to 1 instead of 0 to 12:<ref name=HEVCFebruary2016W1005/>

<math display="block">V=\begin{cases}
\sqrt{3} \cdot L_c^{0.5} & \frac{1}{12} \ge L_c \ge 0,\!\\
a \cdot \ln(12L_c - b) + c & 1 \ge L_c > \frac{1}{12}
\end{cases}</math>

where

*''L<sub>c</sub>'' has a nominal range of 0 to 1 and ''V'' is the resulting nonlinear signal
*the constants ''a'', ''b'', and ''c'' are defined as ''a'' = 0.17883277, ''b'' = 1 - 4''a'' = 0.28466892, and ''c'' = 0.5 - ''a'' ln(4''a'') = 0.55991073

==History==

=== Inception ===
On May 15, 2015, the BBC announced that they had begun work with the NHK to develop a joint HDR proposal that would be proposed to the [[International Telecommunication Union]] (ITU).<ref name=SESHDR2015May>{{cite news |title=High Dynamic Range at the SES Industry Days |author=Simon Thompson |publisher=BBC |url=https://www.bbc.co.uk/rd/blog/2015/05/high-dynamic-range-at-the-ses-industry-days |date=2015-05-15 |accessdate=2015-11-01}}</ref> On June 9, 2015, HLG was proposed to the JCT-VC for [[High Efficiency Video Coding]] (HEVC) and added to the June 2015 draft of the screen content coding extensions.<ref name="HEVCJune2015U0032">{{cite news |title=Proposed addition of transfer characteristics in VUI |author=Y. Nishida |author2=T. Yamashita |author3=A. Ichigaya |author4=T. Shimizu |publisher=JCT-VC |url=http://phenix.it-sudparis.eu/jct/doc_end_user/current_document.php?id=10036 |date=2015-06-09 |accessdate=2015-11-01}}</ref><ref name="HEVCJune2015U1005" />

Later that year, [[Sony]] showed HLG video on a modified HDR display at the [[Society of Motion Picture and Television Engineers|SMPTE]] 2015 conference.<ref name="SonyHLG2015OctoberDisplay">{{cite news |title=Sony Describes Hybrid Log Gamma (HLG) at SMPTE 2015 Event |publisher=DisplayDaily |url=http://www.displaydaily.com/content/videos/32323-sony-describes-hybrid-log-gamma-hlg-at-smpte-2015-event-sony-describes-hybrid-log-gamma-hlg-at-smpte-2015-event |accessdate=2015-11-03}}</ref><ref name="SMPTE2015ATC2015OctoberSMPTE">{{cite news |title=SMPTE 2015 Annual Technical Conference & Exhibition |publisher=[[Society of Motion Picture and Television Engineers]] |url=https://www.smpte.org/ATC |accessdate=2015-11-03}}</ref> [[Colorfront]] announced that their Transkoder 2016 software would support HDR output using HLG.<ref name="ColorfrontHDR2015October">{{cite news |title=Colorfront spotlights amazing UHD HDR performance at SMPTE 2015 |publisher=American City Business Journals |url=http://www.bizjournals.com/prnewswire/press_releases/2015/10/27/MN39583 |date=2015-10-27 |accessdate=2015-11-01}}</ref> [[LG]] announced that their 2015 4K [[OLED]] TVs would support HDR from HLG and [[perceptual quantizer]] (PQ).<ref name="OLEDHDR2015NovemberHDTVtest">{{cite news|author=Vincent Teoh|date=2015-11-06|title=LG Talk Up 4K OLED TV & HDR at UK Briefing|publisher=HDTVtest|url=http://www.hdtvtest.co.uk/news/lg-4k-hdr-201511064202.htm|accessdate=2015-11-08}}</ref> [[Blackmagic Design]] released an update for [[DaVinci Resolve]] that added support for HLG.

[[SKY PerfecTV!]] announced that they will use HLG to transmit 4K [[Ultra-high-definition television|UHDTV]] HDR programming to their satellite subscribers in Japan.<ref name="SKYHDR2015NovemberAdvanced">{{cite news |title=SkyPerfect offers UHD-HDR by DTH |author=Chris Forrester |publisher=Advanced Television |url=http://advanced-television.com/2015/11/04/skyperfect-offers-uhd-hdr-by-dth/ |date=2015-11-04 |accessdate=2015-11-04}}</ref><ref name="DaVinciHDR2015DecemberPro">{{cite news|author=Brian Hallett|date=2015-12-23|title=DaVinci Resolve 12.2 Update & Price Drop|publisher=Pro Video Coalition|url=http://www.provideocoalition.com/davinci-resolve-12-2-update-price-drop|accessdate=2015-12-23}}</ref> [[Harmonic Inc.]] and [[NASA]] announced the HDR capture of an [[Atlas V]] launch which was broadcast the next day on [[NASA TV]] using HLG.<ref name="HDRNASA2015DecemberCNN">{{cite news|title=NASA and Harmonic Explore the Boundaries of UHD at ISS Resupply Launch at Kennedy Space Center |publisher=[[CNN]] |url=https://money.cnn.com/news/newsfeeds/articles/marketwire/11G074496-001.htm |date=2015-12-03 |accessdate=2015-12-05 |url-status=dead |archiveurl=https://web.archive.org/web/20151208170158/http://money.cnn.com/news/newsfeeds/articles/marketwire/11G074496-001.htm |archivedate=2015-12-08 }}</ref> [[Vatican Television Center]] broadcast the ceremony of the Holy Door using HLG and the [[Rec. 2020]] color space.<ref name="RomeHLG2015DecemberAdvanced">{{cite news |title="Huge success" for UHD-HLG test in Rome |publisher=Advanced Television |url=http://advanced-television.com/2015/12/14/huge-success-for-uhd-hlg-test-in-rome/ |date=2015-12-14 |accessdate=2015-12-18}}</ref>

===2016===
Industry bodies:
* The [[Ultra HD Forum]] announced their guidelines for UHD Phase A which includes support for HLG.<ref name="UltraHDGuidelinesApril2016BusinessWire">{{cite news|date=2016-04-18|title=Ultra HD Forum Releases First Industry Guidelines for Deploying End-to-End Live & Pre-Recorded UHD Services in 2016|publisher=[[Business Wire]]|url=http://www.businesswire.com/news/home/20160418006415/en/Ultra-HD-Forum-Releases-Industry-Guidelines-Deploying|accessdate=2016-04-18}}</ref><ref name="UltraHDForumPhaseAApril2016UltraHDForum">{{cite news|date=2016-04-18|title=End-to-end guidelines for phase A implementation|publisher=[[Ultra HD Forum]]|url=http://ultrahdforum.org/resources/phasea-guidelines-description/|accessdate=2016-04-18}}</ref> The Ultra HD Forum also defined HLG with a bit depth of 10-bits, and the Rec. 2020 color space.<ref name="UltraHDForumPhaseAApril2016UltraHDForum" />
* The ITU announced [[Rec. 2100]] which defines two HDR transfer functions which are HLG and PQ.<ref name="Recommendation2100" /><ref name="ITUAnnouncesHDRJuly2016" />
*[[Digital UK]] published their 2017 specification for [[Freeview Play]] which includes support for HDR using HLG.<ref name="FreviewPlaySeptember2016Broadband" />
* The [[Digital Video Broadcasting]] (DVB) Steering Board approved UHD-1 Phase 2 with an HDR solution that supports HLG and PQ.<ref name="DVBUHDPhaseHDRNovember2016News" /><ref name="DVBUHDPhaseHDRNovember2016TVBEurope">{{cite news|author=James Grover|date=2016-11-17|title=UHD-1 Phase 2 approved|publisher=TVBEurope|url=http://www.tvbeurope.com/uhd-1-phase-2-approved/|accessdate=2017-01-07|archive-date=2017-01-13|archive-url=https://web.archive.org/web/20170113023123/http://www.tvbeurope.com/uhd-1-phase-2-approved/|url-status=dead}}</ref> The specification has been published as DVB Bluebook A157 and will be published by the [[ETSI]] as TS 101 154 v2.3.1.<ref name="DVBUHDPhaseHDRNovember2016News" /><ref name="DVBUHDPhaseHDRNovember2016TVBEurope" />
*[[HDMI]] announced that HLG support had been added to the HDMI 2.0b standard.<ref name="HDMI20bIntroduction" /><ref name="HLGHDMI2016Flatpanels">{{cite news|author=Ramus Larsen|date=2016-12-12|title=HDMI 2.0b standard gets support for HLG HDR|publisher=flatpanelshd|url=http://www.flatpanelshd.com/news.php?subaction=showfull&id=1481526782|accessdate=2017-01-07}}</ref><ref name="HLGHDMI2016BBC">{{cite news|author=Andrew Cotton|date=2016-12-31|title=2016 in Review - High Dynamic Range|publisher=BBC|url=https://www.bbc.co.uk/rd/blog/2016-12-bbc-high-dynamic-range-2016|accessdate=2017-01-07}}</ref>

Hardware:
* [[Leader Electronics Corporation]] announced their [[12G-SDI]] waveform monitors with support for HLG.<ref name="12SDIJanuary2016Creative">{{cite news |title=LEADER Announces 12G SDI, HDR and Video over IP Options for its LV 5490 and LV 5480 4K-capable Waveform Monitors |publisher=CreativeCOW.net |url=https://news.creativecow.net/story/880513 |date=2016-01-12 |accessdate=2016-01-13}}</ref> 
* [[Harmonic Inc.]] released an update for the ViBE 4K UHD encoder that added support for HLG.<ref name="HDRHarmonicMarch2016Yahoo">{{cite news |title=Harmonic Showcases Innovation for Agile Video Delivery at 2016 NAB Show  |publisher=[[Yahoo! Finance]] |url=https://finance.yahoo.com/news/harmonic-showcases-innovation-agile-video-120000331.html |date=2016-03-29 |accessdate=2016-04-11}}</ref>
* [[Canon Inc.]] announced that they will release firmware updates for the DP-V2410 and DP-V3010 reference displays to add support for HLG.<ref name="HDRCanonApril2016Redshark">{{cite news |title=Canon reveals new camera and lens in advance of NAB  |publisher=RedShark |url=http://www.redsharknews.com/production/item/3386-canon-reveals-new-camera-and-lens-in-advance-of-nab |date=2016-04-13 |accessdate=2016-04-13}}</ref>
* Sony announced the PVM-X550 OLED monitor with support for HLG.<ref name="OLED550April2016PRNewswire">{{cite news |title=Sony Goes Beyond Definition at NAB 2016 |publisher=[[PR Newswire]] |url=http://www.prnewswire.com/news-releases/sony-goes-beyond-definition-at-nab-2016-300252643.html |date=2016-04-18 |accessdate=2016-04-18}}</ref> Sony also announced a firmware update for the BVM-X300 OLED monitor to add support for HLG.<ref name="OLED550April2016PRNewswire" />
* Sony announced that in October they would release a firmware update to add HLG to their BVM-X300 OLED monitor.<ref name="HLGFirmwareOLEDAugust2016">{{cite news |title=Sony to Update BVM-X300 4K Monitor in October |author=Bryant Frazer |publisher=studiodaily |url=http://www.studiodaily.com/2016/08/sony-to-update-bvm-x300-4k-monitor-in-october/ |date=2016-08-03 |accessdate=2016-08-07}}</ref>
* Sony announced that their VPL-VW675ES projector would support HLG.<ref name="HLGprojectorSeptember2016PRNewswire">{{cite news |title=Sony Electronics Announces the Latest Addition to its 4K HDR Home Theater Projector Line-Up at CEDIA 2016 |publisher=PR Newswire |url=http://www.prnewswire.com/news-releases/sony-electronics-announces-the-latest-addition-to-its-4k-hdr-home-theater-projector-line-up-at-cedia-2016-300327954.html |date=2016-09-14 |accessdate=2016-09-23}}</ref>
* The Trusted Reviews website reported that [[Samsung]] had told them that all of their 2016 HDR TVs could support HLG with a firmware update.<ref name="SamsungFirmwareHLGNovember2016TrustedReviews">{{cite news |title=Hybrid Log–Gamma: Why it's the next big thing in 4K TV |author=Steve May |publisher=Trusted Reviews |url=http://www.trustedreviews.com/opinions/hybrid-log-gamma-what-is-it |date=2016-11-04 |accessdate=2017-01-10}}</ref>
* Atomos updated their [[Shogun Inferno]] product to include HLG input and output for recording, monitoring, editing and layout from cameras and computers as well as to HLG compatible TVs.<ref name="HLGShogun20164K">{{cite news |title=Atomos Shogun Inferno Firmware 8.1 Unlocks Sony FS 2K/Raw Super-Slow Motion |author=Ogy Stoilov|publisher=4K Shooters |url=http://www.4kshooters.net/2016/12/25/atomos-shogun-inferno-firmware-8-1-unlocks-sony-fs-2kraw-super-slow-motion/ |date=2016-12-25 |accessdate=2017-01-10}}</ref>

Software:
* [[Avid Technology]] released an update for [[Media Composer]] that added support for HLG.<ref name="HDRAvidMarch2016Avid">{{cite news |title=How Avid is Advancing Key Industry Trends Highlighted at the HPA Tech Retreat 2016 |author=Wim Van den Broeck |publisher=[[Avid Technology]] |url=http://www.avidblogs.com/how-avid-is-advancing-key-industry-trends-highlighted-at-the-hpa-tech-retreat-2016/ |date=2016-03-11 |accessdate=2016-04-04}}</ref><ref name="HDRAvidJanuary2016studiodaily">{{cite news |title=Avid Media Composer 8.5 Adds HDR, Simplifies Menus, Offers Better Feedback on the Timeline |author=Bryant Frazer |publisher=studiodaily |url=http://www.studiodaily.com/2016/01/avid-media-composer-8-5-adds-hdr-simplifies-menus-offers-better-feedback-on-the-timeline/ |date=2016-01-29 |accessdate=2016-04-04}}</ref> 
* [[Google]] announced [[Android TV]] 7.0 which supports HLG.<ref name="AndroidHDRSeptember2016Android" /><ref name="AndroidTVSeptember2016Flatpanels">{{cite news |title=Android TV 7.0 supports Dolby Vision, HDR10 and HLG |author=Ramus Larsen |publisher=flatpanelshd |url=http://www.flatpanelshd.com/news.php?subaction=showfull&id=1473405995 |date=2016-09-07 |accessdate=2016-09-23}}</ref>

Broadcasters:
* [[Dome Productions]] announced that they will begin trials of HLG to deliver HDR content.<ref name="HDRDomeApril2016Yahoo">{{cite news |title=Dome Productions to Begin Trialing of HLG for Delivering HDR |publisher=Yahoo! Finance |url=https://ca.finance.yahoo.com/news/dome-productions-begin-trialing-hlg-171500211.html |date=2016-04-15 |accessdate=2016-04-15}}</ref>
* [[SKY Perfect JSAT Group]] announced that on October 4 they will start the world's first 4K HDR broadcasts using HLG.<ref name="HLGBroadcastsJuly2016">{{cite news |title=4K HDR from SKY Perfect JSAT |author=Colin Mann |publisher=Advanced Television |url=http://advanced-television.com/2016/07/29/4k-hdr-from-sky-perfect-jsat/ |date=2016-07-29 |accessdate=2016-07-30}}</ref>
* [[Eutelsat]] announced that it will launch a new channel using HLG.<ref name="EutelsatHLGSeptember2016">{{cite news |title=IBC 2016: Eutelsat fast forwards in the video age |publisher=Eutelsat |url=http://news.eutelsat.com/pressreleases/ibc-2016-eutelsat-fast-forwards-in-the-video-age-1549968 |date=2016-09-07 |accessdate=2016-09-07}}</ref>
* [[Google]] announced that [[YouTube]] will start streaming HDR videos which can be encoded with HLG or PQ.<ref name="GoogleTrueHDRNovember2016Google">{{cite news |title=True colors: adding support for HDR videos on YouTube |author=Steven Robertson |url=https://youtube.googleblog.com/2016/11/true-colors-adding-support-for-hdr.html |date=2016-11-07 |accessdate=2017-01-11}}</ref><ref name="GoogleUploadHDRNovember2016Google" />
* The [[BBC]] announced that it was adding a 4-minute HLG edit from their [[Planet Earth II]] series to its [[BBC iPlayer]] IPTV platform for public UHD testing.<ref name="BBCiPlayerHLGTrial2016">{{cite news|title=BBC announces arrival of HLG content on its iPlayer IPTV platform|author=Dave Bevan|date=2016-12-08|accessdate=2016-12-08|publisher=BBC|url=https://www.bbc.co.uk/mediacentre/latestnews/2016/planet-earth-2-uhd}}</ref>
* [[Mediapro/Overon]] announced that they will transmit the Spanish Football League (LFP) worldwide using 4K HDR broadcasts based in HLG

===2017===
Industry bodies:
* ATSC released the video standard for [[ATSC 3.0]] which includes support for HLG.<ref name="ATSC3VideoMay2017" />

Hardware:
* [[LG Corporation]] announced that their 2017 Super UHD TVs will support HLG.<ref name="LGTVJanuary2017Forbes">{{cite news |title=LG Takes Aim At Samsung With New 'Quantum Dot-Beating' TV Technology |author=John Archer |work=Forbes |url=https://www.forbes.com/sites/johnarcher/2017/01/03/lg-takes-aim-at-samsung-with-new-quantum-dot-beating-tv-technology/ |date=2017-01-03 |accessdate=2017-01-07}}</ref>
* [[Panasonic]] announced that their 2017 OLED TV will support HLG.<ref name="PanasonicTVJanuary2017Wired">{{cite news |title=Panasonic launches 'world's first' HDR, ultra-HD OLED TV |author=Matt Burgess |publisher=Wired |url=https://www.wired.co.uk/article/panasonic-ez1002-television-4k-hdr-ultra-hdr |date=2017-01-04 |accessdate=2017-01-07}}</ref>
* [[Sony]] announced that their 2017 OLED TVs will support HLG.<ref name="SonyTVGJanuary2017Forbes">{{cite news |title=Sony Unveils Debut OLED TV Range |author=John Archer |work=Forbes |url=https://www.forbes.com/sites/johnarcher/2017/01/04/sony-unveils-debut-oled-tv-range/ |date=2017-01-04 |accessdate=2017-01-07}}</ref>
* [[JVC]] announced that their 2017 4K projectors will support HLG.<ref name="JVCHLGJanuary2017JVC">{{cite news |title=New JVC 4K e-Shift4 Projectors Deliver Higher Brightness and Contrast, Add Low Latency Mode |publisher=[[JVC]] |url=http://pro.jvc.com/pro/pr/2017/ces/CES17_new_eshift4_projectors.html |date=2017-01-05 |accessdate=2017-01-16}}</ref>
* LG Corporation announced that they will add support for HLG to their 2016 OLED TVs and their 2016 Super UHD TVs with a firmware update.<ref name="LGFirmwareHLGJanuary2017Flatpanelshd">{{cite news |title=LG will bring HLG HDR to 2016 OLED & LCDs through firmware update |author=Ramus Larsen |publisher=flatpanelshd |url=http://www.flatpanelshd.com/news.php?subaction=showfull&id=1484051855 |date=2017-01-04 |accessdate=2017-01-07}}</ref>
* Sony announced that they will add support for HLG to their 2017 4K TVs with a firmware update.<ref name="SonyFirmwareHLGJanuary2017Flatpanelshd">{{cite news |title=Sony: Android TV 7.0 coming to 2017, 2016 & 2015 TVs |author=Ramus Larsen |publisher=flatpanelshd |url=https://www.flatpanelshd.com/news.php?subaction=showfull&id=1484553703 |date=2017-01-16 |accessdate=2017-01-16}}</ref>
* Panasonic announced that they will add support for HLG to several models of their 2016 4K TVs with a firmware update.<ref name="PanasonicFirmwareHLGFebruary2017Flatpanelshd">{{cite news |title=Panasonic will add HLG HDR support to select 2016 TVs |author=Ramus Larsen |publisher=flatpanelshd |url=http://www.flatpanelshd.com/news.php?subaction=showfull&id=1487319665 |date=2017-02-17 |accessdate=2017-03-04}}</ref>
* [[Philips]] announced that their 2017 4K TVs will support HLG and that they will add support for HLG to several models of their 2016 4K TVs with a firmware update.<ref name="PhilipsFirmwareHLGMarch2017Flatpanelshd">{{cite news |title=Philips: HLG HDR update coming to 2016 TVs |author=Ramus Larsen |publisher=flatpanelshd |url=http://www.flatpanelshd.com/news.php?subaction=showfull&id=1489426063 |date=2017-03-13 |accessdate=2017-03-13}}</ref>
* Sony began releasing firmware updates for several of their 2016 and 2017 Android TV models which adds support for HLG.<ref name="SonyFirmwareHLGMay2017Flatpanelshd">{{cite news |title=Android 7.0 will roll out to Sony TVs starting May 31 |author=Ramus Larsen |publisher=flatpanelshd |url=http://www.flatpanelshd.com/news.php?subaction=showfull&id=1496115817 |date=2017-05-31 |accessdate=2017-05-31}}</ref>
* Panasonic released firmware update 2.0 for the [[Panasonic Lumix DC-GH5]] which added support for HLG recording.<ref name="PanasonicFirmwareGH5September2017">{{cite news |title=Panasonic Releases GH5 Firmware 2.0 with Anamorphic and More |author=Daron James |publisher=No Film School |url=https://nofilmschool.com/2017/09/panasonic-gh5-adds-anamorphic-and-more-firmware-update |date=2017-09-28 |accessdate=2017-12-09}}</ref>
* Panasonic began releasing firmware updates for several of their 2016 TV models which adds support for HLG.<ref name="PansonicFirmwareHLGNovember2017Flatpanelshd">{{cite news |title=Panasonic releases HLG HDR update for select 2016 TVs |author=Ramus Larsen |publisher=flatpanelshd |url=https://www.flatpanelshd.com/news.php?subaction=showfull&id=1511781178 |date=2017-11-27 |accessdate=2017-12-05}}</ref>
* [[Qualcomm]] announced the [[Qualcomm Snapdragon]] 845 which includes support for HLG.<ref name="Qualcomm845December2017">{{cite news |title=Qualcomm lifts the veil on the Snapdragon 845 SoC |publisher=Tech Report |author=Bruno Ferreira |url=https://techreport.com/news/32933/qualcomm-lifts-the-veil-on-the-snapdragon-845-soc |date=2017-12-06 |accessdate=2017-12-09}}</ref>

Software:
* [[Adobe Systems]] announced updates to [[Adobe Creative Cloud]] which includes support for HLG.<ref name="AdobeCreative2017April2017Adobe">{{cite news |title=The Latest (and Greatest!) for Premiere Pro CC and Media Encoder |publisher=[[Adobe Systems]] |url=https://blogs.adobe.com/creativecloud/the-latest-and-greatest-for-premiere-pro-cc-and-media-encoder/ |date=2017-04-19 |accessdate=2017-04-20}}</ref>
* [[Apple Inc.|Apple]] released a firmware update for [[Final Cut Pro X]] which includes support for HLG.<ref name="FinalCutHLGDecember2017">{{cite news |title=Final Cut Pro X 10.4 adds HDR support, VR video editing, and (finally!) curves |publisher=DPReview |author=Brittany Hillen |url=https://www.dpreview.com/news/0999542997/final-cut-pro-x-10-4-adds-hdr-support-vr-video-editing-and-finally-curves |date=2017-12-14 |accessdate=2017-12-17}}</ref>

Broadcasters:
* [[Eutelsat]] announced that their [[Hot Bird]] video service would include the [[Travelxp]] 4K channel which uses HLG.<ref name="TravelxpHLGJanuary2017Eutelsat">{{cite news |title=Eutelsat scales up Ultra HD content with two new channels at the popular Hotbird neighbourhood |publisher=[[Eutelsat]] |url=http://news.eutelsat.com/pressreleases/eutelsat-scales-up-ultra-hd-content-with-two-new-channels-at-the-popular-hotbird-neighbourhood-1721477 |date=2017-01-04 |accessdate=2017-01-14}}</ref>
* The BBC announced that [[Blue Planet II]] would be available in 4K HDR on the [[BBC iPlayer]] using HLG.<ref name="BluePlanetHDRDecember2017BBC" /> Blue Planet II will be available on the BBC iPlayer service from December 10, 2017 to January 16, 2018.<ref name="BBCiPlayerBluePlanetDecember2017">{{cite news |title=How can I watch Blue Planet II in Ultra HD on my connected TV? |publisher=BBC |url=https://www.bbc.co.uk/iplayer/help/latest-news/blue-planet-II-uhd |date=2017-12-05 |accessdate=2017-12-06}}</ref> The BBC states that almost 400 TV models have support for HLG which includes TV models from [[Finlux]], [[Hisense]], Hitachi, LG, Panasonic, Philips, Samsung, Sony, and Toshiba.<ref name="BluePlanetHDRDecember2017BBC" /><ref name="BBCiPlayerBluePlanetDecember2017" />
* [[DirecTV]] began broadcasting HLG HDR on their 4K Channels 104 and 106.<ref name="DirectvHLGDecember2017Sportsvideo" /><ref name="DirectvHLGDecember2017HDGuru" />

===2018===

* [[Vizio]] announced HLG support for their 2018 models.<ref>{{Cite news|url=https://www.techhive.com/article/3268764/smart-tv/vizio-courts-cord-cutters-challenges-oled-and-adds-new-hdr-options-to-its-2018-smart-tv-lineup.html|title=Vizio courts cord cutters, challenges OLED, and adds new HDR options to its 2018 smart TV lineup|work=TechHive|access-date=2018-10-26|language=en}}</ref>

===2019===

* [[Panasonic]] announced HLG support in their S1 and S1R full frame mirrorless cameras which will be released in March 2019.<ref>{{Cite news|url=https://www.dpreview.com/news/7318697757/panasonic-s1-s1r-to-ship-in-march-hlg-photo-and-high-res-mode-added-to-feature-list|title=Pansonic S1, S1R to ship in march, HLG photo and high res mode added to feature list|work=DpReview news|access-date=2019-01-10|language=en}}</ref>

===2020===

* [[Sky UK]] announced that their popular [[Sky Q]] box will get HLG support from May 27, 2020.<ref>{{Cite news|url=https://www.pocket-lint.com/tv/news/sky/152314-sky-q-will-finally-get-hdr-on-wednesday-23-may-2020.amphtml|title=Sky Q will finally get HDR on Wednesday 27 May 2020|work=Pocket Lint News|access-date=2020-05-25|language=en}}</ref>
* [[Apple Inc.|Apple]] released the [[iPhone 12]] series with HLG video recording support via [[Dolby Vision]] profile 8.4, which adds a Dolby Vision metadata layer on top of HLG footage.<ref>{{Cite web|last=Patel|first=Nilay|date=2020-10-20|title=Apple iPhone 12 Pro review: ahead of its time|url=https://www.theverge.com/21524288/apple-iphone-12-pro-review|access-date=2020-10-20|website=The Verge|language=en}}</ref>

==See also==
* [[Dynamic range]]
* [[Gamma correction]]
* [[High-dynamic-range rendering]]
* [[High-dynamic-range imaging]]
* [[High-dynamic-range video]]

==References==
{{Reflist}}

==External links==
*[http://www.arib.or.jp/english/html/overview/doc/2-STD-B67v1_0.pdf ARIB STD-B67]
*T. Borer and A. Cotton, [http://downloads.bbc.co.uk/rd/pubs/whp/whp-pdf-files/WHP309.pdf A "Display Independent" High Dynamic Range Television System], BBC Research & Development White Paper WHP 309, September 2015

{{Dynamic range color representation}}

{{DEFAULTSORT:Hybrid log-gamma}}
[[Category:High dynamic range]]
[[Category:Television technology]]