HDR means high dynamic range. It lets a television show a larger gap between the darkest and brightest parts of a picture, along with a wider range of colours. A TV specification often lists several HDR formats, and they are not all the same.
Why formats exist
An HDR video file carries extra information about brightness and colour. The format defines how that information is stored and how the TV should interpret it. A TV can only display a format it supports, so a set that lacks one will usually fall back to the basic version or to standard dynamic range.
HDR10
HDR10 is the base format and is supported almost everywhere HDR is offered. It uses static metadata: one set of brightness instructions applies to the whole film or programme. This works, but a very dark scene and a very bright scene are treated with the same settings.
HDR10+
HDR10+ builds on HDR10 by adding dynamic metadata, which can change from scene to scene or even frame to frame. The TV can then adjust its brightness mapping more precisely. It is an open format, and its licence terms differ from those of Dolby Vision.
Dolby Vision
Dolby Vision also uses dynamic metadata and supports up to 12-bit colour, compared with 10-bit in HDR10. It requires hardware and licensing from Dolby, so the logo appears on selected sets. Many streaming services and discs offer it. In practice, the real-world gain depends on how capable the panel is, since a TV with low peak brightness cannot show the full effect of any format.
HLG
HLG stands for hybrid log-gamma. It was designed for broadcast television and live content. It needs no separate metadata, and the same signal can be shown on both HDR and older non-HDR sets. You are most likely to meet it in live sport and some broadcast channels.
What to check on a product page
- HDR10 is expected on any set that advertises HDR at all.
- If you use a particular streaming app or player, check which formats it delivers, then check the TV supports the same one.
- Support for several dynamic formats is useful, since content comes from different sources, but it does not replace a bright, high-contrast panel.
- The HDMI input also matters: HDR at 4K and high refresh rates needs a suitable HDMI version, typically HDMI 2.0 or 2.1.
A note on brightness
An HDR logo does not guarantee a strong HDR picture. The effect comes from peak brightness, local dimming or self-lit pixels, and colour range. A budget panel can accept an HDR signal and still show it quite flat. Treat the format list as a compatibility guide, and use brightness and contrast figures to judge how impressive the result will be.