Out-of-Service Cameras
Cameras may become out-of-service for a variety of reasons, including power loss, cabling problems, equipment failures, and more. All cameras in Vizzion's camera API are continuously monitored. If a roadside or hotspot camera becomes out-of-service for an extended period, the camera's DetectedOutOfService field will be set to True (see GetCamerasInBox). If an on-vehicle camera which generated Drive streams goes out of service, the vehicle's Online field will be set to False. It is recommended that out-of-service cameras and Drive streams should be hidden by the application instead of displaying disabled markers or error messages.
Cameras may also have temporary image problems for a variety of reasons, including transmission failure, agency intervention, poor lighting, and more. At any given time, temporary image problems affect 3-10% of all camera images, mostly at night. To counter this, dynamic image checks are performed on every image prior to return from the Camera API, and an error is returned instead if the image fails these checks (see GetCameraImage). If the application is attempting to display a single camera image, and an error is returned from the Camera API, it is recommended that the application display a message such as “Image unavailable”. If the application is displaying multiple camera images, such as a list of cameras along a particular route, it is recommended to dynamically hide all images that return an error from the Camera API.
Note: Dynamic checks are not currently performed on roadside camera video streams or Drive streams.
Note: Applications with critical reliability requirements (e.g., live broadcast) can use the pre-test and cache feature (see GetCamerasInBox) to ensure 100% reliability of all images for at least 10 minutes.