To get unit video settings use request unit/get_video_settings. Required access to unit 'View detailed item properties'

svc=unit/get_video_settings&params={
 "itemId":long
}			  

{"settings":[
  {"flags":1,"name":"cam"}, /* name = camera name, flags = 1 camera is active */
  {"flags":3,"name":"cam1"},/* name = camera name, flags = 3 camera and video saving is active */
  ...]
}