According to the Dahua API spec 1.67, the following should cause the camera to pan relatively 100*
http://xxx.xxx.xxx.xxx/cgi-bin/ptz.cgi?action=start&code=Relatively&channel=0&arg1=100&arg2=0&arg3=0&Arg4=0
However, it results in:
Error
Bad Request!
A little digging shows a JS method named...