HDR Label Decoder

The number in the name is the minimum peak brightness in nits, measured on a small white patch. Under CTS 1.2 that patch covers 8% of the screen, and under CTS 1.1 it covered 10%. The other rows matter as much. A tier also sets how bright the full screen has to get, how dark black has to stay with white on screen, how much of the DCI-P3 color range the screen covers, and how fast it gets bright.

The classic tiers, 400 to 1400, mostly show up on LCDs with a backlight. Their black level limit drops from 0.4 nits at DisplayHDR 400 to 0.02 nits at DisplayHDR 1400. The True Black tiers are meant for screens that light each pixel on their own, like OLED. Every True Black tier caps black at 0.0005 nits and asks for a rise to peak within 2 frames. In return, each one asks for less on a full screen flash than the classic tier with the same number.

CTS is VESA's test spec. CTS 1.2 came out on May 7, 2024 and replaced CTS 1.1 from September 4, 2019. VESA's FAQ says a certification doesn't expire, so a monitor in a store today can carry a logo it earned under either one.

The tables show what changed. DisplayHDR 400 used to need 95% of BT.709 and had no DCI-P3 minimum. Under CTS 1.2 it needs 99% of BT.709 and 90% of DCI-P3. CTS 1.2 measures peak brightness on a smaller patch, and its summary lists tests the CTS 1.1 summary doesn't, like a static contrast ratio for the classic tiers, an average color error and a subtitle flicker check. True Black 1000 and 1400 only exist in CTS 1.2. Switch the version above to see each table.

DisplayHDR 400 doesn't. VESA's FAQ says local dimming isn't required by the spec at the 400 level, so an edge lit monitor that runs its whole backlight at one level can carry the logo. Under CTS 1.2 the panel then needs high contrast of its own, at least 1,300:1 in one image, or it needs 1D local dimming. Under CTS 1.1 there was no such test. That's why a DisplayHDR 400 monitor can turn a night sky gray around a bright moon.

From DisplayHDR 500 up, local dimming is part of the deal. CTS 1.2 asks for 1D local dimming or better at 500 and 600, and 2D local dimming or better at 1000 and 1400. CTS 1.1 only said local dimming from 500 up. True Black tiers skip the backlight question. Their black limit is built for screens like OLED, where each pixel makes its own light.

With 1D dimming the LEDs sit along one edge in groups, so each zone is a strip of the screen. With 2D dimming they sit behind the panel in a grid, as in full array and mini LED monitors, so each zone is a small patch. The local dimming guide shows what each one does in a dark scene and where blooming comes from.

HDR10 is the base format. It uses the PQ curve, 10-bit color and one set of static metadata for a whole video, and nearly every HDR screen accepts it. That's why it says nothing about quality.

HDR10+ and Dolby Vision add dynamic metadata, new tone mapping data per scene or per frame. It helps most when a screen is much dimmer than the display the video was mastered on. A screen can only use it when the source sends it, like a streaming app or a player that supports that format. HLG comes from broadcast TV and has no metadata at all.

None of these formats make a screen brighter. A dim monitor with Dolby Vision is still a dim monitor, so check the DisplayHDR tier or a review for that.