Saving Disk Space using H265

Hi,

We have just tried to used H265 with and IDIS camera (DC-T4831HRX-A) and it then causes the camera to reset all the time.
In the ONVIF settings we don't get a H265 profile and have tried selecting
“Keep camera stream and profile settings”
What can we do to get this working.

Also, any recommendations to reduce the disk use.
Thanks
Andy