HDR & colour
HDR metadata: MaxCLL, MaxFALL, mastering display
The numbers inside an HDR10 signal that tell a display how bright the content is.
What is it?
Static HDR10 metadata (SMPTE ST 2086) contains: mastering display primaries and white point, mastering display max/min luminance (e.g. 1000 / 0.0001 nits), MaxCLL (brightest single pixel in the whole film) and MaxFALL (brightest average frame). Displays use these to choose a tone-mapping curve. Wrong or missing values (very common on streaming and games) cause dim or clipped HDR.
Why it matters with the HDfury Vertex²
The HDfury Vertex² decodes the metadata in human-readable form, lets you edit every field and inject it — fixing sources that send zeros, lowering MaxCLL for a dim projector, or telling a display it is receiving a 1000-nit master when it is not. This is the 'HDR Fixer' feature and it works in real time at any resolution.
How to use it on the Vertex²
Web server → HDR/DV → Custom HDR metadata generator: EOTF, Primaries, White point, Max luminance, Min luminance, MaxCLL, MaxFALL → Create IF → Send HDR, with one of the 'Use custom HDR…' checkboxes enabled. Values are stored and survive power cycles.
Related terms
- HDR10 — The baseline HDR format: 10-bit, PQ curve, BT.2020 with static metadata.
- EOTF / PQ (SMPTE ST 2084) — The brightness curve of HDR: PQ for HDR10/Dolby Vision, HLG for broadcast, gamma for SDR.
- Infoframes: AVI, VSIF, SPD, AUD, HVS, HFV — Small data packets sent with every frame that describe the picture, sound and source.
- Tmax / Tmin (DV datablock luminance) — The maximum and minimum brightness you tell a Dolby Vision player your display can show.