Content Light Level
Owner: Apple Inc
Contact: Nicolas Bonnier (nbonnier@apple.com), Luke Wallis (wallis@apple.com)
Change date: Registered 04-06-2025, amended 28-07-2025
Category: HDR Image
Name: CLL
Meaning of name: CLL describes light level of the image content.
Usage restriction: Optional
Display name element: Content Light Level
| Value | Meaning | Display element |
|---|---|---|
| Floating point number, floating point number, 8-bit number | Floating point numbers describe light level characteristics (maximum and average) of the image content, calculated as specified in CTA-861.3-A, Annex A for a single frame. Value of 0.0 means that the respective value is unknown. 8-bit number defines color primaries as per ITU‑T H.273. Per the same specification, primaries value of 2 means that primaries cannot be expressed by ITU‑T H.273 but they are determined by the application. In the case of CLL metadata entry it means that the primaries are defined by tags required by a three-component matrix-based display profile containing this metadata. |
Content Light Level |
Changelog Entry updated on 2025-07-28 to add the reference to CTA-861.3-A. Entry updated on 2025-07-31, adding reference to primaries value of 2.