This is the most critical part of the filename. It signifies an Event or "Emergency" file. These are usually triggered automatically by a G-sensor (detecting a collision or sudden braking) or manually by the user pressing a "lock" button. mp4: The standard video file format.
Because this is marked as an "event" file, most dashcams will it, meaning it will not be overwritten by the normal loop recording cycle until you manually delete it or format the SD card. a_27_ev.mp4
Typically represents the date (the 27th day of the month) or a sequential file number from that recording session. This is the most critical part of the filename
Often indicates the "A" channel, which usually refers to the front-facing camera in a multi-camera setup. most dashcams will it