Standards bodies are slowly progressing towards a recommendation for sharper contrast technology HDR in UHD TV standards, but difficult choices still have to be made, ANGA COM attendees heard this morning.
David Wood, CM-UHD TV chairman at the DVB Project Office, outlined steps to date, current thinking and the choices still to be made on HDR in a presentation at the show in Cologne.
Wood said that the HDR TV recommendation of the ITU-R is now due on July 4. He said that the recommendation for HDR, which can be applied to 4K and 8K video, but also to existing 1080p HD TV, includes both the Perceptual Quantizer (PQ) system – recommended by Dolby – and the Hybrid Log Gamma (HLG) system, developed originally by the BBC and NHK. Wood said the ITU-R should have a recommendation on PG or HLG soon.
In addition to the ITU-R recommendation, Wood said that the DVB Project has to agree the delivery format for UHD-1 Phase 2, including for IP delivery. The DVB has agreed a phased approach, with the Phase 2 spec scheduled for completion by the end of this year. Phase 2 has two so-called Conformance Points, designated CPA and CPB, each with different features to cater for two groups of DVB members with different priorities.
CPA includes HDR for adopters that want to start services in 2017 with HDR only, while CPB includes both HDR and Higher Frame Rates (HFR) for adopters that want to wait until 2019 to launch UHD TV services with both elements.
The UHD-1 Phase 2 spec also provides both backwards compatible and non-backwards compatible versions of HDR. Wood said that proponents of non-backwards compatibility version maintain that such regimes have never worked in the past. Advocates of backwards compatibility maintain that there will be no loss of quality compared to non backwards compatibility.
The HDR requirements outline that it may be necessary to choose more than one solution to cover all commercial requirements.
“If we can we’d like to avoid a plurality of systems,” said Wood. However, he said, the question of backwards compatibility remained open.
“Will there be a single or multiple specification for HDR? Please follow the discussion at the DVB up to the end of this year and you will know,” said Wood.