Art-directable Continuous Dynamic Range video

We present a novel, end-to-end workflow for content creation and distribution to a multitude of displays that have different dynamic ranges. The emergence of new, consumer level HDR displays with various peak luminances expected in 2015 gives rise to two new research questions: (i) how can the raw source content be graded for a diverse set of displays both efficiently and without restricting artistic freedom, and (ii) how can an arbitrary number of graded video streams be represented and encoded in an efficient way. In this work we propose a new editing paradigm which we call dynamic range mapping to obtain a novel Continuous Dynamic Range (CDR) video representation, where the luminance of the video content, instead of being a scalar value, is defined as a continuous function of the display dynamic range. We present an interactive interface where CDR videos can be efficiently created while providing full artistic control. In addition, we discuss the efficient approximation of CDR video using a polynomial series approximation, and its encoding and distribution to an arbitrary set of target displays. We validate our workflow in a subjective study, which suggests that a visually lossless CDR video representation can be achieved with little bandwidth overhead. Our solution can be implemented easily in the current distribution infrastructure and consists of transmitting two gradings and an additional meta-data stream, which occupies less than 13% current standard video distribution bandwidth.