Please follow below steps to turn on the Win10 Stream HDR video function:
1. Use another Win10 PC/NB and graphics card that supports the HDR function and then connect to the monitor for the crosscheck.
2. Go to Win10 System > Display > Turn "ON" HDR setting in Win10 HDR WCG.
3. Open the Settings App and Navigate to Settings > Apps > Video Playback > Turn "ON" Stream HDR Video function.
If the issue still exists after the steps have been performed, please contact BenQ local service center.