15 stops DR? With current Sony sensors, 12bit ADC readout maxes out at 12 stops of DR.
With the Dual Gain HDR, it's a Digital Overlap Drive with double rolling shutter and half the framerates. Not very practical for cinematic work. But Fujifilm has already kind of implemented this DOL drive in X-T3/30 and GFX100, with the shutter speed slower than frame rate feature.