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ABSTRACT

Interest in High Dynamic Range (HDR) for live broadcasting continues to increase. Well publicised trials completed within the past year have proven that Ultra High Definition (UHD) images with HDR can be captured, delivered and displayed to viewers on HDR-capable TV screens (1)(2).

A number of broadcast organisations are now moving to the next phase of development, drawing up plans to implement permanent on-air UHD services including HDR. In most cases, the new services will be delivered alongside existing High Definition programming and in many cases a simultaneous Standard Dynamic Range (SDR) feed at 3840 x 2160 resolution will be required.

This paper will examine the technical and operational challenges presented. An example of a production infrastructure designed from first principles to overcome these challenges is provided.

INTRODUCTION

The first public demonstrations of the live production and delivery to home of 3840 x 2160 images were held in the early 2010s. These early trials prioritised the broadcast of higher resolution images over increased dynamic range or wider colour gamut. They were the result of advances in technology throughout the content production, delivery and display chain, alongside a close collaboration between the broadcasters, outside broadcast service providers, telecommunications providers and equipment vendors involved. The trials paved the way for the first 4K UHD services on air today.

Recent advances in areas such as image capture, OETF/EOTF conversion, colour space management and home display technology, along with developments in industry standardisation have created the possibility of live UHD broadcast services with the addition of HDR and Wide Colour Gamut (WCG).

Against this background, this paper examines a real-world technical infrastructure designed specifically for a 4K UHD service with High Dynamic Range. The system under review has been designed for the regular broadcast of live sports events where UHD services with HDR are delivered alongside UHD Standard Dynamic Range and HD services.

The paper describes the physical infrastructure employed and highlights the various UHD, HDR, SDR and HD sources included within the system. The use of the S-Log3 transfer function as the production OETF is examined. The location of the various colour space and OETF/EOTF conversions are also shown.

The production infrastructure under study is based upon a number of practical systems that have been implemented around the world. These include the system at Canadian Communication and Media Company, Rogers Cable for forthcoming 4K UHD live services.

In additional to the description of the technical infrastructure, the paper also examines the operational considerations to be addressed. The operational set up and live adjustment of picture parameters have been key factors evaluated within live broadcast trial to date. The paper provides recommendations for adjustment and monitoring of images within the programme chain to provide maximum quality for the various deliverables.

The controls available to the operators are explained. The results obtained continue to drive product development and the paper examiners the state of play in today’s systems.