HDR, short for high dynamic range, is a video and display technology that reproduces a much wider range between the darkest and brightest parts of an image, together with a wider color gamut, than standard dynamic range (SDR). In displays, HDR describes both the signal formats that carry this extra information and the panel capabilities, chiefly peak brightness, black level and color volume, needed to show it.
SDR content was mastered for a reference brightness of about 100 nits and the Rec. 709 color space. HDR content is mastered with highlights of 1,000 nits or more and wider color primaries, so a capable screen can show sunlight reflections, neon signs and dark shadow detail in the same frame. Display HDR is distinct from HDR photography, which merges several exposures into one still image.
How HDR video encodes brightness and color
HDR relies on three technical changes compared with SDR. The first is a new transfer function that maps code values to light: the Perceptual Quantizer (PQ, SMPTE ST 2084) describes absolute luminance up to 10,000 nits, while Hybrid Log-Gamma (HLG) is a relative curve designed for broadcast. The second is a wider color space, Rec. 2020 as the container, with most content mastered inside the smaller DCI-P3 gamut. The third is 10-bit or 12-bit depth, which provides enough steps to avoid visible banding across the larger range.
Because no consumer display reaches every value the signal can describe, the screen performs tone mapping: it compresses highlights and colors that exceed its capabilities into the range it can show. The quality of tone mapping strongly affects how HDR looks, often more than the format label itself.
| Property | SDR | HDR |
|---|---|---|
| Reference peak brightness | About 100 nits | Mastered at 1,000 to 4,000 nits, signal up to 10,000 |
| Transfer function | Gamma (BT.1886) | PQ or HLG |
| Color container | Rec. 709 | Rec. 2020 |
| Bit depth | 8 bits typical | 10 or 12 bits |
| Metadata | None | Static or dynamic, format dependent |
HDR formats: HDR10, HDR10+, Dolby Vision and HLG
Several HDR formats coexist, and they differ mainly in how metadata guides tone mapping. Static metadata describes the whole title once, while dynamic metadata adjusts the mapping scene by scene or frame by frame, which helps displays with limited brightness.
| Format | Transfer function | Metadata | Typical use |
|---|---|---|---|
| HDR10 | PQ | Static (mastering display, MaxCLL, MaxFALL) | Baseline for discs, streaming, games |
| HDR10+ | PQ | Dynamic, royalty-free | Some streaming services and TVs |
| Dolby Vision | PQ | Dynamic, licensed, up to 12-bit | Streaming, discs, mobile devices |
| HLG | Hybrid Log-Gamma | None, backward compatible | Live broadcast and some cameras |
HDR10 is the universal fallback: almost every HDR display and source supports it, and the other PQ formats usually include an HDR10 base layer. HLG avoids metadata entirely and still looks acceptable on SDR screens, which makes it practical for live television.
What a display needs for convincing HDR
Accepting an HDR signal is easy; showing it well is not. Visible HDR quality depends on peak brightness, contrast in small areas, black level and color volume. A display that reaches only about 300 to 400 nits and has a modest native contrast ratio can decode HDR10 but delivers little real benefit, and sometimes looks dimmer than SDR because tone mapping darkens the image.
| Panel type | Strength for HDR | Main weakness |
|---|---|---|
| OLED and QD-OLED | Per-pixel light, perfect blacks | Lower full-screen brightness, burn-in risk |
| Mini-LED with local dimming | Very high peak brightness | Blooming around bright objects |
| Edge-lit LCD | Low cost | Weak local contrast, raised blacks |
| MicroLED | High brightness and per-pixel control | Very high cost, limited availability |
Certification programs help buyers compare monitors. The VESA DisplayHDR tiers set minimum peak brightness levels, such as 400, 600 and 1000 nits, and add separate True Black tiers for emissive panels. For televisions, local dimming zone count, measured peak brightness on a 10 percent window and the processing quality of tone mapping are better guides than the logo alone.
Setting up HDR correctly
A working HDR chain needs every link to support it: the content, the playback device or graphics card, the cable and port, and the display mode. HDMI 2.0 or DisplayPort 1.4 is the usual minimum for 4K HDR at 60 Hz, and higher refresh rates may require HDMI 2.1 or newer DisplayPort versions.
| Symptom | Likely cause | Fix |
|---|---|---|
| Washed-out desktop | SDR content shown in HDR mode without proper mapping | Adjust SDR brightness slider or toggle HDR per use |
| Dim HDR image | Low-brightness panel or power saving mode | Disable eco modes, use a brighter display |
| Clipped highlights | Wrong peak brightness calibration | Run the HDR calibration tool for the display |
| Banding in gradients | 8-bit output or heavy compression | Set 10-bit output, use higher bitrate source |
| No HDR option | Cable, port or input setting limits bandwidth | Enable enhanced input mode, use certified cable |
On computers, games benefit most when they render natively in HDR. Operating-system features that convert SDR games to HDR can help but may produce inaccurate brightness, so a short display calibration with the system’s HDR calibration tool is worthwhile.
Misconceptions about HDR
- HDR is not just brighter: its value comes from highlights and shadows together, while average picture level often stays similar to SDR.
- An HDR logo is not a quality guarantee: many budget screens accept HDR signals without the brightness or contrast to show them.
- More nits is not always better: poor local dimming can create halos that hurt the image more than lower peak brightness.
- HDR is not the same as wide color gamut: a display can cover DCI-P3 without delivering HDR contrast.
Stripped to the essentials
Look out of a window on a sunny day: you can see both the bright sky and the dark shade under a tree. Ordinary video squashes that range, so bright skies turn flat white or shadows turn black. HDR keeps much more of the difference between bright and dark, and it shows richer colors too.
To see the benefit, you need both HDR content and a screen that can actually get very bright in small spots while keeping dark areas dark. The screen matters as much as the label.
Where it is applied
A family buys a new television with Mini-LED local dimming and a measured peak brightness of about 1,500 nits on small highlights. They stream a nature documentary mastered in Dolby Vision, with a fallback HDR10 layer, through a streaming box connected by a certified HDMI cable to an HDMI 2.1 port.
In a night scene with a full moon over a dark forest, the moon appears bright and crisp while the dark trees still show texture, instead of the gray haze typical of SDR. During setup, they notice that the HDR picture looks dim until they switch off the energy saving mode and select the filmmaker picture preset. Correct settings, not only the hardware, made the difference in the final image.