What is HDR?

The pursuit of High Dynamic Range (HDR) is the dream of getting closer to the Human Visual System (HVS) in all that we experience as viewers.

  • HDR is a new display system that is designed to better represent what the human vision system (HVS) can see.
  • Human vision sees the world with lots of dynamic range and a wide range of colors.
  • Modern cameras have up to 14 stops of dynamic range.
  • BT.709 Standard Dynamic Range (SDR) systems can show only up to the equivalent of about 6 stops.
  • HDR attempts to show much more of the world we see, starting with the larger camera dynamic range available today at source and through the production chain and ultimately for presentation on affordable displays optimized for HDR.

HDR and Single Master Workflow

To learn more about the benefits of a single master workflow for HDR and SDR, download the informative PDF below.

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HDR and Its Impact on Workflow

To learn more about the benefits of a better pixel with HDR, download the informative PDF below.

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HDR Videos

HDR Benefits Video

Watch AJA Product Manager Bob Hudelson explain the benefits of HDR for real time production and the retention of artistic intent that HDR helps preserve.

HDR Productions and Conversion Techniques

Large investments are made in production tools and technology to create compelling HDR content only to have a small but growing audience view it. Native HDR cameras, SDR cameras, SDR/HDR replay machines, SDR graphics, and inserts all have to be processed together in a single HDR production format or success is elusive. HLG BT.2020 is the common production format today but distribution formats are often PQ BT.2020 and SDR BT.709. This means that from production to distribution, high quality color gamut and dynamic range converters are an absolute requirement.

At the SMPTE 2021 Toronto Technical Conference, Tim Walker, Senior Product Manager at AJA Video takes us through HDR fundamentals and conversion techniques that allow you to get more into and more out of your HDR production all of which can be realized using AJA’s FS-HDR.

HDR Conversion Techniques Roundtable

At the SMPTE 2021 Toronto Technical Conference Bryce Button (AJA Video) moderated a panel of speakers to discuss new tools to meet the ever changing needs of HDR productions and what is driving them.

Panelists include Bill Feightner (Colorfront), Bob Hudelson (AJA Video), Bruno Munger (Colorfront), Nick Shaw (Antler Post/Cromorama), and Tim Walker (AJA Video).

PQ (Perceptual Quantizer) or Finding a Better Curve

To achieve a balance of getting closer to human perception within the bandwidth limitations of existing infrastructure and technologies, including chroma and luminance sampling, bit depth, and the strengths and weaknesses of Gamma vs Logarithmic curves, a better curve was needed.

Why was a better curve needed and what is the advantage of PQ*?

  • Power functions waste bits at the high end of the luminance range
  • Log functions waste bits at the low end of the luminance range
  • Gamma fails at low luminance levels, even at higher bit depths
  • Greatest efficiency would be to follow human perception
  • PQ Shows balanced performance across the entire luminance range

* PQ is represented in practice by two approaches, HDR10 an open approach and Dolby® Vision, a proprietary system owned by Dolby Laboratories. Both are designed to make the most efficient use of bits throughout the range of luminance and contrast steps possible.

PQ is standardized in SMPTE ST 2084 and BT.2100 and PQ defines a curve that ensures banding is below the Just Noticeable Difference (JND). The PQ curve ensures the most efficient use of code words which minimizes the bit depth required.

HDR Approaches

Tackling the Challenges of HDR

  • HDR involves the need to take disparate color spaces and logarithmic representations from various camera manufacturers and move it through the process to final delivery for emerging HDR approaches for display and delivery today.
  • Broadcasters and producers want to take the wide dynamic range available from cameras and preserve as much of it as possible, to offer end viewers increased contrast and luminance ranges, a broader and richer color palette and an immersive viewing experience.
  • HDR approaches avoid confusion by helping manage the color space properly, making sure applications look correct and take optimal advantage of improved display capabilities.
  • One challenge is to convert from Camera formats, such as RAW and Log, to one of the emerging HDR approaches. Additionally, be able to apply and/or convert the HDR approach of choice through the editing, color correction and/or monitoring process.
  • Many UltraHD displays now include HDR functionality, which provides a more realistic and immersive viewing experience. This is achieved by increasing the color space representation with Wide Color Gamut (WCG) and luminosity by using higher dynamic range (HDR).

Emergent Systems Address HDR Needs

For a vivid image, which HDR promises upon delivery to the display, the challenge has been to provide enough useful steps within the color and luminance range to provide smooth gradations and satisfy the viewer. Dolby Vision is a new way of defining how a picture looks on a TV. It is a "display referred" system where each code value defines a specific brightness (i.e. there is no user brightness control). Dolby Vision has a method to send 12-bit data down a HDMI cable utilizing 4096 shades for smooth gradations. For contemporary production pipelines, the challenge is that most pipelines are 10-bit with 1024 shades or steps available. HDR 10, Dolby Vision and HLG have been designed to solve this dilemma by efficiently choosing to utilize curves across the luminance and color ranges that minimize perceptual banding and achieve results that are closer to the human vision system, enabling incredible results.

  • Proprietary format
  • SMPTE ST-2084 Perceptual Quantizer (PQ)
  • Metadata: Dynamic per ST 2094*
  • Electro-optical transfer function, up to 4K resolution
  • Playback bit depth: 12-bit
  • Up to 10,000-nit maximum brightness (mastered to 4,000-nit in practice)
  • Wide Color Gamut (WCG) color space (ITU-R Rec. 2020)

HDR10 is a Media Profile defined by the Consumer Technologies Association (CTA).

HDR10 uses SMPTE ST-2086 "Mastering Display Color Volume" static metadata to send color calibration data of the mastering display, as well as MaxFALL (Maximum Frame Average Light Level) and MaxCLL (Maximum Content Light Level) static values. HDR10 is an open standard supported by a wide variety of companies.

  • Open format
  • SMPTE ST-2084 Perceptual Quantizer (PQ)
  • Minimum Signal Interface: HDMI 2.0a
  • Playback color representation BT.2020 (same as Dolby Vision)
  • Playback transfer function: ST 2084 (same as Dolby Vision)
  • Metadata: Static per ST 2086
  • Playback bit depth: 10-bit

HDR10+ builds from HDR10*, adding dynamic metadata and more, allowing for scene by scene or even shot by shot variation. The standard allows for recognizing a display's color space and more. Samsung is the primary driver for this evolution of the original standard.

HDR10+ has recently been adopted by a range of companies and resulted in the creation of the HDR10+ Alliance with members comprising Amazon, Samsung, Panasonic, 20th Century Fox, and Warner Bros and more.

  • SMPTE 2094-40 Dynamic Metadata for Color Volume Transforms (DMCVT)
  • Color transforms optimized for each scene, and each display
  • Metadata: Dynamic per ST 2094
  • Metadata tracks carry supplementary color grading information
  • Minimum Signal Interface: HDMI 2.0a
  • Playback color representation BT.2020 or BT.709 dependent on display
  • Playback transfer function: ST 2084
  • Playback bit depth: 10-bit

HLG (Hybrid Log Gamma) is an HDR approach that was jointly developed by the BBC and NHK. HLG uses relative luminance values and builds on the BT.2020 standard for a wider color gamut and adds PQ and HLG dynamic range for a standard known as BT.2100. The HLG standard is royalty free and is compatible with SDR displays as well as HDR displays. HLG is supported by HDMI 2.0b*, HEVC, and VP9. The key appeal of HLG is that HDR content can be reasonably viewed on SDR displays.

  • Hybrid between Gamma and Log
  • Metadata: None
  • Relative Luminance
  • Very similar to SDR curve
  • Playback bit depth: 10-bit
  • Linear light image data from a camera is mapped to the HLG OETF Curve and to the WCG color space BT.2020

*Since HLG has no metadata, HLG works with any HDMI spec and HDMI 2.0b is a clarification of HDMI 2.0a

Conversions: FS-HDR, FS4, ColorBox

FS-HDR with Colorfront Engine™ Technology

  • FS-HDR is designed to bridge the conversions needed from camera log formats and SDR sources to HDR formats, from SDR to HDR to integrate non-HDR cameras and materials into HDR programming, and HDR to SDR for SDR deliverables, all in real time.
  • Inside FS-HDR is the Colorfront Engine™, designed by Colorfront's Academy Award® winning CTO Bill Feightner and Academy Award® winning lead engineer Tamas Perlaki, that provides real time wide color gamut, high dynamic range, high frame rate up to 60p, and high resolution processing.
Real time HDR/WCG conversion examples:
  • Convert SDR/BT.709 to PQ/BT.2020
  • Convert SDR/BT.709 to HLG/BT.2020
  • Convert PQ/BT.2020 to SDR/BT.709
  • Convert PQ/BT.2020 to HLG/BT.2020
  • Convert HLG/BT.2020 to SDR/BT.709
  • Convert HLG/BT.2020 to PQ/BT.2020
  • Convert camera Log formats to PQ/BT.2020
  • Convert camera Log formats to ACEScct
Robust HDR Toolset:
  • Colorfront Engine TV Mode algorithm and controls for live television productions
  • Colorfront Engine Live Mode algorithm and controls for live broadcast, A/V, and venue applications
  • Colorfront Engine Film Mode algorithm and controls for On-Set Camera Preview and Look Creation
  • Licensed BBC HLG conversion mathematical mapping LUTs that conform to ITU BT.2408
  • NBCU LUTs developed by NBCUniversal Media, LLC for live television productions
  • Supports user uploads of custom 33 point 3D LUTs
  • Dynamic LUT mode for integration with 3rd party LUT tools
  • Configurable HDR settings for SDI output VPID
Configurable To Support Your Workflow
  • Configure as Single 4K/UltraHD processor or four independent 2K/HD/SD processors
  • Input and Output formats: 4K, UltraHD, 2K, HD, and SD
  • Input and Output frame rates: 23.98, 24, 25, 29.97, 30, 50, 59.94, and 60
  • YCbCr 4:2:2 10 bit
  • Can store, recall, export, and import configuration presets
  • Supports Single Master Workflow paradigm

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Extensive SDI interfacing options
  • 12G/6G/3G/1.5G-SDI support
  • Single, dual, and quad link support
  • Two Sample Interleave (2SI) or Square Quad Division (SQD) pixel mapping
  • BNC or Fiber LC
  • Note: 12G-SDI and fiber available with optional SFP modules


FS4 is a 4-channel 2K/HD/SD or 1-channel 4K/UltraHD frame synchronizer and up, down, cross-converter and so much more. This combination frame synchronizer and converter offers incredible versatility and connectivity in a sleek 1RU frame for all your 4K/UltraHD and 2K/HD/SD conversion needs. FS4 Offers a wide range of connectivity for both video and audio including optional SFP’s for single link 12G-SDI connectivity. For HDR workflows, the FS4 supports automatic or configurable HDR metadata generation for the SDI output VPID and HDMI output HDR Infoframe.



ColorBox from AJA is a compact, high-performance converter for color managed workflows designed to specifically meet the conversion needs of broadcast, live events, and on-set applications. Supporting Standard Dynamic Range (SDR), High Dynamic Range (HDR), and Wide Color Gamut (WCG) signals, it utilizes 12G-SDI for single wire 4K/UltraHD HDR up to 4:2:2 10-bit 60p or 4:4:4 12-bit 30p with a unique color processing pipeline.

Built around the 33pt. 3D LUT processor with tetrahedral interpolation, AJA Color Pipeline provides additional 4x 1D LUTs and 2x 3x3 matrices that are each individually configurable even as Proc Amps or RGB Color Correctors. Easily manage color processing options via the web user interface which can be accessed directly from a wired Ethernet connection or through a wireless connection via a 3rd party WiFi USB adapter.

ColorBox expands its capabilities by offering licensable upgrade options for advanced color managed workflows, including the Colorfront Engine, BBC HLG LUTs and ORION-CONVERT. ORION-CONVERT’s unique real time floating point math approach to color transforms produces higher precision results to get “access to the colors between the colors.” This enables pixel perfect color transforms and round tripping where maintaining colors is paramount. Included for free in ColorBox are transforms from Colorfront and the NBCU LUTs providing yet more professional color processing options to choose from.

ColorBox also offers a sophisticated test pattern generator and frame store, bringing useful tools to your workflow, including the ability to capture up to a 4K image as a 16-bit .tiff file for the highest quality reference stills. ColorBox can even overlay information onto the image, including helpful user definable text fields and user loaded overlays. These captures can be saved locally on ColorBox or onto a connected computer for collection and referencing wherever needed.


AJA HDR Solutions for Editing and Color Correction

You need to be able to view and display your HDR materials to compatible monitors during postproduction. AJA Desktop solutions make this simple with support provided in AJA Control Panel for setup of HDR metadata and HLG. With AJA Desktop Software v16.0 and the AJA Control Room application, many AJA desktop devices now offer:

  • HDR over SDI. VPID signaling is now available for SDR/HDR Transfer Characteristics, Colorimetry and Luminance over SDI, bringing flexible output options to your AJA device. HDMI ports that were already HDR compatible will work simultaneously, for HDR output via both SDI and HDMI.
  • HDR Metadata Capture. AJA Control Room software adds support for HDR metadata capture from an incoming SDI or HDMI signal. The captured .mov video file will have embedded HDR metadata, allowing the file to be played back at its intended dynamic range.
  • HDR Auto Playback Detection. AJA Control Room software also provides HDR Auto Playback Detection. Embedded HDR metadata in a recorded .mov file, is read and used to automatically set the HDR format on the monitor(s) connected to the AJA HDMI and/or SDI outputs. Support for file-based .mov HDR outputs with metadata from Adobe Premiere Pro/Adobe Media Encoder HDR files is also available. Screening those rendered outputs is a simple and hi-quality experience with AJA Control Room. Every frame is presented in its full-quality, at the timing intended, and with the proper HDR format set correctly and automatically.
  • KONA 5 for desktop 12G-SDI I/O with HDR10* and HLG** support over HDMI 2.0 and SDI

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  • KONA 4 for desktop I/O with HDR10* and HLG** support over HDMI and SDI

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  • KONA 1 for desktop I/O with HDR10* and HLG** support over SDI

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  • Io 4K Plus for Thunderbolt 3 I/O with HDR10* and HLG** support over HDMI

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  • T-TAP Pro for Thunderbolt 3 with 12G-SDI and HDMI 2.0 desktop output for HDR10* and HLG** via HDMI and SDI.

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  • Developers can utilize AJA’s latest SDK toolkits to develop solutions for HDR10+ deployment.

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  • Developers who are Dolby Vision licensed can tunnel Dolby Vision through AJA’s KONA 5, KONA 4 and Io 4K products

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* Check with your software manufacturer for compatibility.

**HLG support is application dependent. Check with your software manufacturer for compatibility.

Game Capture, VR and Projection Mapping with HDR

Gaming capture, eSports, VR and projection mapping can take great advantage of HDR for their immersive environments. To capture HDMI sources with HDR for these needs look to KONA HDMI.


KONA HDMI is an 8-lane PCIe 2.0 multi-channel HDMI capture card, with all of the quality and flexibility you have come to expect from AJA.

Designed for the demands of multiple workflows such as gaming, streaming, VJ-ing, live events switching, vlogging, VR, post and broadcast, this powerful card boasts support for single channel capture up to 4K/UltraHD 60p or four channel capture up to 2K/HD 60p.

KONA HDMI provides support for accepting HDR signals captured over HDMI from gaming stations like the PS4® Pro.


HDR Monitoring

HDR Monitoring from SDI Sources


Hi5-4K-Plus Mini-Converter for HDR and high frame rate support

Standards for HDR over SDI are still evolving and HDMI 2.0 HDR capable displays are affordable and available.

Look to AJA's popular 3G-SDI to HDMI Hi5-4K-Plus Mini-Converter for HDR10 and HLG workflows to feed your display.

Use AJA's free Mini-Config application along with Hi5-4K-Plus to pass-through or override HDMI HDR Infoframe Metadata as defined in CTA-861-G and HDMI 2.0a.

Plug in, set your static metadata when necessary, and go.

Hi5-4K-Plus OG-Hi5-4K-Plus


12G-SDI to HDMI 2.0 Conversion with HDR support

Hi5-12G converts a 4K/UltraHD/2K/HD 12G-SDI single-link input with eight channels of embedded digital audio to an HDMI 2.0 output with two or eight channels of audio. It includes a 12G-SDI single-link input with a re-clocked SDI loop out for simpler confidence monitoring or pass on for SDI pipelines. The Hi5-12G can also generate HDR metadata in accordance with HDMI v2.0 and CTA-861-G.

Fiber SFP-equipped Hi5-12G models include the Hi5-12G-R receiver, which extends HDMI 4K signals over long distances from either an SDI or a Fiber connected source, and the Hi5-12G-TR transceiver, which delivers a 4K/UltraHD SDI or Fiber source signal to an HDMI destination with pass on of the source through SDI or Fiber to a secondary destination.

Hi5-12G is also available with a Fiber ST connector as the Hi5-12G-R-ST receiver, offering the same long distance benefits as its Fiber SFP variant.

Hi5-12G Models Available:

Hi5-12G   -   12G-SDI to HDMI 2.0
Hi5-12G-R   -   Includes 1x Fiber LC Receiver
Hi5-12G-TR   -   Includes 1x Fiber LC Transceiver
Hi5-12G-R-ST   -   Includes 1x Fiber ST Receiver


HDR and Wide Color Gamut Monitoring Support

AJA offers several Mini-Converter products for a wide range of formats that support monitoring of HDR and Wide Color Gamut sources, including:

HDR Playback and Recording from AJA

Ki Pro Ultra 12G

  • Ki Pro Ultra 12G offers HDR recording for HDR10 and HLG. Set the Ki Pro Ultra 12G to capture ProRes and the recorded file will preserve the HDR metadata.
  • Ki Pro Ultra 12G can also be used to playback HDR material in HDR10 or HLG formats via it’s HDMI 2.0 output by utilizing the appropriate menu selection.
  • Incoming 4K HDR video can also be received via single cable 12G-SDI or by utilizing the SFP fiber cages for longer distances.
Ki Pro Ultra 12G

HDR Analysis

HDR Image Analyzer 12G

Waveform, Histogram and Vectorscope Monitoring for HDR

HDR Image Analyzer 12G delivers a comprehensive array of tools for the effective analysis of the latest HDR standards – including HLG, PQ and Rec.2020 – in 8K/UltraHD2/4K/UltraHD/2K/HD in a convenient 1RU device.

Developed in partnership with Colorfront®, AJA HDR Image Analyzer supports a wealth of inputs from camera Log formats to SDR (REC 709), PQ (ST 2084) and HLG and offers color gamut support for BT.2020 alongside traditional BT.709.

Specifically designed to be used wherever needed, the 1RU form factor fits into a range of workflows, providing the confidence you need for consistent and predictable HDR production and mastering.

HDR Analysis Tools

Included in AJA’s HDR Image Analyzer’s toolsets are waveform, histogram and vectorscope monitoring, plus a host of essential image analysis features such as: nit light level meter; out of gamut false color mode making it easy to spot out of gamut or out of brightness pixels; error logging; pixel picker; framestore with split screen; line mode, which can focus the region of interest onto a single horizontal or vertical line; audio phase metering and built-in support for the most prevalent camera color spaces including ARRI®, Canon®, Panasonic®, RED® and Sony®.

  • Waveform
  • Histogram
  • Vectorscope
  • Color Gamut
  • Nit Light Level
  • File Based Error Logging with Timecode
  • Data Analyzer with Advanced Pixel Picker
  • Advanced, Out of Gamut and Out of Brightness Detection with Error Tolerance
HDR Image Analyzers


HDMI 2.0 to 12G-SDI Conversion

You've been handed an HDR signal over HDMI 2.0 and need to know more about the HDR metadata being utilized. Connect your HDMI 2.0 cable from the source to AJA's HA5-12G HDMI to 12G-SDI Mini-Converters and open AJA's free Mini-Config software to its HDR Metadata tab for a read out of any HDR static metadata present. The HA5-12G also supports HDR signaling metadata pass-through or optional override.

AJA’s HA5-12G allows users to convert an HDMI 2.0 input to two 12G-SDI single link outputs. It includes two SDI DA outputs and transmits 12G-SDI on each SDI link, reducing cable runs when transporting 4K/UltraHD SDI. HA5-12G supports up to 8-Channels of audio from the HDMI source or 2-Channel analog audio (RCA), with eight or two channels of digital embedded audio on 12G-SDI.

A Fiber SFP-equipped HA5-12G model is available, the HA5-12G-T single-channel transmitter, which extends HDMI 4K signals over long distances (10 km Single-Mode).

HA5-12G is also available with a Fiber ST connector as the HA5-12G-T-ST offering the same long distance benefits as its Fiber SFP variant.

HA5-12G Models Available:

HA5-12G   -   HDMI 2.0 to 12G-SDI
HA5-12G-T   -   Includes 1x Fiber LC Transmitter
HA5-12G-T-ST   -   Includes 1x Fiber ST Transmitter



You've been handed an HDR signal over HDMI and need to know more about the HDR metadata being utilized. Connect your HDMI 2.0 cable from the source to AJA's HA5-4K HDMI to SDI Mini-Converter and open AJA's free Mini-Config software to its HDR Metadata tab for a read out of any HDR static metadata present and the ability to pass it through to the SDI VPID or override.

HA5-4K OG-HA5-4K