Realtime Cross-Mapping of High Dynamic Range Images

Abstract

The ability to deliver high dynamic range (HDR) and wide colour gamut (WCG) imagery is crucial to next generation broadcast. It is a key feature of both DVB UHD-1 Phase 2 and the latest ITU-R recommendation: BT.2100. While this is an important step towards the creation of broadcast HDR-WCG systems, if HDR-WCG production is to be deployed commercially, it is necessary to use a mix of both conventional standard dynamic range (SDR) and HDR cameras in a single HDR-WCG production. It is also necessary to derive a high quality conventional ITU-R BT.709 (SDR with gamma nonlinearity) programme for regular contribution and transmission. Additionally, it is necessary to cross-map SDR programmes, interstitials and adverts into an HDR-WCG service for transmission. This paper describes the techniques that have been developed to perform these transforms to meet broadcast production standards in real-time. These techniques are built on the experience gained in the creation of the first fifty HDR theatrical releases, as well as trials with HDR broadcast productions. Finally, the operational practices to ensure consistency in HDR-WCG production, high quality programme interchange, and a pleasing viewer experience are examined.