Recent display technologies (LCD backlight, OLED) allow watching images with more contrast and more saturated colors than even digital cinema. Unfortunately, today's video content and broadcast cannot convey such colors due to the currently used colorimetry standard (ITU-R.BT 709). Solutions exist for more contrast and wider color gamut, but they are different in the video and photography worlds. New standardization initiatives for video (IEC 61966-2-4, ITU-R) try to set up a new, extended but fixed colorimetry, while digital photography applies - since a decade – flexible color management (ICC). However, in all these approaches the color gamut of either devices or contents is not described explicitly. This paper presents the new international standard IEC 61966-12-1 “Metadata for identification of colour gamut (Gamut ID)”. This standard allows the precise and flexible description of a color gamut. The metadata supports graphics hardware, scalability, memory footprint efficiency, convex handling of non-convex gamuts, handling of fuzzy color gamuts, and handling of gamut cusps. This standard may be used in future systems for video color management or for image-dependent gamut mapping.