The growing interest in (live) High Dynamic Range (HDR) production has created a need for efficient ways to verify that video signal chains are set up correctly – a need that is even more acute where a conversion to SDR (ITU-R BT.709) is also required, as field tests by the EBU and its Members have shown. To address this need, the EBU Video Systems group has now released a new type of colour bars – a test image – specifically designed for use in HDR production environments using the popular HLG standard. The colour bars specification is published as EBU Tech 3373.

Many tests in one

The bars allow users to quickly and easily perform a number of essential tests to verify the correct behaviour of the chain or identify issues:

  • Display-light conversion from HLG to SDR;
  • Scene-light conversion from HLG to SDR;
  • Unexpected tone-mapping or signal clipping (luma ramp);
  • Unexpected sub-blacks removal (near-black test signal)
  • Limitations of displays in rendering saturated colours (saturation test);
  • Faulty 'Quad 3G-SDI (2SI)' connections.

This last test is especially useful in current SDI-based setups, where connection mistakes such as swapped cables can easily occur. Thanks to a clever pattern design, the resulting image will identify if a cable has been disconnected and which (if any) cables are swapped.

The elements published in the EBU Tech 3373 specifcation include documentation on how to create the new HDR Colour Bars and pseudo-code. Also available are two TIFF representations of the colour bars: one in HD resolution (1080) and one with a 2160 raster. The colour bars reserve space for customization, such as added logos, station names, production titles or similar.

Webinar on 27/05/2020

Special credits for the creation of EBU Tech 3373 go to BBC R&D – and in a webinar on 27 May 2020 at 16:00 CEST, BBC R&D's own Simon Thompson will explain the HDR colour bars and how to use them. If you are looking for a crash course on using the colour bars, or want to learn more about the principles used, please register for the webinar.

Providing test signals if one of the ways in which the EBU supports high quality HDR production. See the HDR section for more information on related activities.

Latest news