French Open Reflections: Euromedia’s Serge Beaupère discusses latest HDR trials

Four Sony HDC-4300s were used during the HDR trials at this year’s French Open.

As well as a 12-camera 4K production, 28 February’s Olympique Lyonnais vs PSG match at Stade de Gerland in Lyon, France, saw Euromedia undertake a series of High Dynamic Range (HDR) production trials. More recently still, the broadcast and technical services supplier participated in a further sequence of HDR tests during the French Open at Roland Garros.

Serge Beaupère, who is engineer in charge at Euromedia, is one of the company’s leading camera specialists and took an overseeing role during the latest trials. “We had done the one HDR trial in February, but in truth it wasn’t in live. Only one camera was recorded in XAVC with SLOG 3 curve for post production edit with some HDR equipment,” he recalls.

“But at Roland Garros, using a configuration of four Sony HDC4300s over four days of trials, it was the first time that we produced a real live workflow in HDR from camera to TV receiver. We tested a beta software of HLG NHK inside the camera. On a BVM-X300 monitor directly out of the camera with a HLG preset, the HDR picture really is much better than SDR in black and especially in bright light.”

Despite the improvement, Beaupère certainly isn’t without reservation about the current capability of simultaneous HDR and SDR on a single workflow production. “For now the wide gamut is OK, but the gap between higher dynamic range and the standard dynamic range is not enough with this beta HLG NHK,” he says. “The low and middle curve is too low and doesn’t boost the SDR signal sufficiently. It’s impossible with outside lights to have a normal level in rec 709 SDR and at the same time to have a significantly improved HDR picture.

“Sony provided two solutions to compensate here in the form of two 4K slot output cameras: one SDR and the other HDR. As a result, we can decrease the SDR gain [with regard to] increasing the gap with HDR. We test with -9 db and -12 db. On the BVM -X300 with a normal level SDR, the HDR picture is really improved – but we do need to use two workflows.

“With a single workflow in the BVM-300 we can provide a boost to gamma Rec 709, which compensates for the low level curve SDR. That works enough well with this new curve.

“It would be interesting to test HLG BBC HDR, which has a different low and middle curve. We hope that it would fit the gamma curve and would deliver an improved SDR and HDR dynamic gap.”