A clapperboard is a tool often used in the movie industry. This is a film or movie slate, usually in black and white, often depicted as the ultimate symbol of film, or the process of shooting one. 

It has a very important purpose - although it may not be obvious from the outside. It is meant for video editors.

The clapperboard is meant to assist them set the accurate marks on the provided footage, so that they can synchronize the audio with the variety of shots.

This app was developed to serve as a digital sort of clapperboard. In case you do not have access to the hardware, so to speak - you can simply open this app - fill up the important details like scene, shot, take, title, date and time. As an extra perk, there is a countdown so that the AI takes on that other important film production role - 

The "clap" is crisp and solid, and has a value of 1kHZ audio signal. 

The slate is available in both portrait and landscape modes.