Alibi

Alibi turns an Android phone into a dashcam. It records continuously while running, but keeps only a recent window of that footage, so storage does not fill up over a long drive. When something happens worth keeping, the user saves the window and the last stretch of recording, described as thirty minutes, is written out as a file instead of being discarded.

The point of this design is that the decision to record comes after the event rather than before it. A driver does not need to anticipate an incident and press record in time; the recording is already there, and the save action retains it.

Myzel394 publishes Alibi under the GPL-3.0-only licence. It is listed for Android, so it depends on the phone's own camera and storage rather than on separate dashcam hardware.