HDR10 is the format doing the actual work behind almost every "HDR" badge you see on a TV box, a monitor spec sheet, or a streaming service's content details. It's open and royalty-free, which is exactly why it became the mandatory baseline — anything that wants to claim UHD Blu-ray or mainstream streaming HDR support has to support HDR10 at minimum, whether or not it also supports something fancier on top.
What HDR10 actually specifies
- 10-bit color depth — more brightness/color steps than the 8-bit depth standard video has used for decades, which matters because HDR's wider brightness range needs finer steps to avoid visible banding.
- PQ as the transfer function — see what PQ is — an absolute mapping from a signal value to a real-world brightness in nits, rather than the relative gamma curve SDR video uses.
- Rec. 2020 color primaries — see what Rec. 2020 is — a substantially wider color gamut than the Rec. 709 primaries SDR video is graded in.
- Static HDR metadata — MaxCLL (maximum content light level) and MaxFALL (maximum frame-average light level), each set once for the entire video and never changed scene to scene.
The trade-off in that last point
Static metadata is HDR10's biggest practical limitation. One number describing the brightest moment across an entire two-hour film has to be a compromise — a display tone-maps every scene against that same ceiling, whether the scene is a blinding daytime exterior or a dim nighttime interior. Dolby Vision and HDR10+ both exist specifically to fix this, by letting that metadata change per scene or per frame instead of staying fixed. HDR10 itself never got that upgrade; it's deliberately the simple, universal baseline.
Video HDR vs. photo HDR
It's easy to assume every "HDR" label works the same way, but HDR10 solves a video-and-broadcast problem: how do you carry brightness metadata alongside a video signal so displays know how to render it. HDR photos — the kind you've likely taken on a recent phone, and the kind Encode builds — use a completely different mechanism, a gain map bundled directly into the image file. If you're trying to understand a specific HDR photo rather than a TV spec sheet, the gain map article is the more directly relevant one.