BBC Blue Planet 2 4K HLG HDR iPlayer trial for Freeview Play TVs begins December 10

The BBC is launching a second UHD trial on iPlayer which will see all seven episodes of Blue Planet 2 available in 4K with HLG (Hybrid-Log Gamma) HDR. This second experiment is a considerable advance of the first, and will be available on “over 300 devices,” beginning December 10.

All that will be needed is a compatible UHD TV which supports the IP streaming protocol DVB-DASH. DASH is part of the Freeview Play and DTG D-Book specification. While Samsung does not have Freeview Play on its TVs,Samung PR confirmed support to Inside CI saying: "We don’t support Freeview Play but we do support HLG on our 2017 and 2016 TVs so we are compatible with the new BBC 4K iPlayer Trial coming on December 10."

The trial will utilise adaptive bitrate streaming, to cope with variable broadband speeds. There will be eleven encodes each delivering different viewing experiences: 3840 x2160 requires 22.7Mbps. This then slides to: 3200 x 1800 at 15.8Mbps, 2560 x 1440 at 10.1Mbps, 1920 x1080 at 7Mbps, 1600 x 900 at 4.8 and 1280 x720 at just 2.5Mbps.

The UHD version of Blue Planet 2 was post-produced in HLG HDR, and then encoded into HEVC at 25fps. Each version, a ‘representation, is accompanied by stereo sound encoded as AAC-LC at 128 kbit/s.

The use of HLG means that viewers will not necessarily need an HDR TV to benefit from the higher UHD resolution and wider colour gamut of the new UHD iPlayer bitstreams. HLG is backwards compatible with SDR 4K TVs that support a wider BT.2020 colour gamut.

The results of this trial are said to be key to developing a third trial, so it seems we are still some way off a regular UHD service on iPlayer. “Our goal with these trials is always to leave the BBC with a better operational capability for the next trial,” says BBC R&D.