Thanks Cliff.
I forgot this @*ù$ protection frown

In this case, a UHD player should downscale the signal to 1080p.

I have read a exemple with a Sony X800 player linked to VPL-HW55 projector through a Marantz 8801.
The signal is downscaled to 1080p 4:4:4 12 bits. And the result seems to be better than a BR disk.

Does the HD621 support this format ?

Serge.

G68ADV + HD621 (dead)
2xBSS 366
LCR Yamaha DSR112
4 Surround Presonus Eris E8
1 JBL 4645C sub and 1 DIY sub with WGTI15 woofer (Crest Audio 8001 amplifier)
3D-Lab Dvd Master/Panasonic BDT700/Panasonic UB420
JVC X7900