I have IP cameras (Hikvision) that can only alert me via emails and FTP when the camera alarm is triggered. I wish I can make use of the IP cameras as motion detectors for my HASS setup.
The easiest way I can think of is to use the camera’s FTP function to upload new snapshot to an FTP server or to the same computer running HASS. Once “the sensor” find a new file in the monitored folder, it will change its state to “on” for few seconds. This state change can be used as trigger for automation like any other motion sensor.