Beyond BT.709

The recent High Efficiency Video Coding (HEVC) standard and current progress in the specification of HDMI 2.0 has revived discussion about video colorimetry. For years, BT.709 was successfully used to define the primary chromaticities of display devices and transformation to the Y'Cb'Cr' color space that is used for the compression of HD video. Current advances in display technologies, along with the introduction of Ultra High Definition Television (UHDTV), makes the following question more relevant than ever before: Can we do better than BT.709? — This paper tries to answer this question by highlighting methods of extending the color gamut, showing the difficulties in the transformation from one color space to another, and pointing out the different conversion methods used to represent RGB data in the Y'Cb'Cr' color space. It emphasizes the importance of Constant Luminance Transform for color perception and compares BT.709 to BT.2020 from different viewpoints. Finally, the advantages and disadvantages of switching to BT.2020 are presented from a broadcast engineering perspective.