Platform

Platform is a physical entity, such as an aircraft, helicopter, drone, or vehicle that carries one or more sensors.

Mission

Mission is a collection of recordings from a platform's sensors, together with descriptive metadata.

Sensor

Sensor is a logical entity that produces one independent video stream or another type of data stream.\ For example, for an aircraft platform, it can be an EO/IR camera, tail camera, radar, operator's screen, or audio source.

Clip

A clip is a continuous recording. A session may contain several clips separated by periods with no recording.

Recording hierarchy

Missions are recorded in HLS format.

HlsVideoSensor stores video segments using the following hierarchy:

├── MissionName/   
│   ├── SensorName/
│   │         ├── MissionMasterManifest.m3u8 
│   │         ├── MissionVideoManifest.m3u8 
│   │         ├── MissionManifest-0-CC.m3u8  
│   │         ├── Clip1  
│   │         │      ├── ClipMasterManifest.m3u8 
│   │         │      ├── ClipVideoManifest.m3u8
│   │         │      ├── Manifest-0-CC.m3u8   
│   │         │      ├── Clip1-1-0.ts 
│   │         │      ├── Clip1-1-0.vtt 
│   │         │      ├── Clip1-1-1.ts 
│   │         │      ├── Clip1-1.vtt 
│   │         │      ├── ....
│   │         │          
│   │         ├── Clip2
│   |         │      ├── ClipMasterManifest.m3u8 
│   │         │      ├── ClipVideoManifest.m3u8
│   │         │      ├── ClipManifest-0-CC.m3u8   
│   │         │      ├── Clip2-2-0.ts 
│   │         │      ├── Clip2-2-0.vtt 
│   │         │      ├── ....

MissionManifest is a higher-level manifest that points to the video / vtt segments inside the clips. It is created and updated dynamically (to accommodate non-continuous clips in one continuous playlist). The recorder splits recorded video into segments.

GOP-aligned recording

Segments must begin at GOP (Group of Pictures) boundaries to allow seamless switching between nonconsecutive segments, as shown below: