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 load video */
  {"flags":0,"name":"cam1"},/* name = camera name, flags = 0 no loading video */
  ...]
}