This piece is called Capall. The video visually depicts the development of some found sounds over the space of almost a minute.

It was inspired by an electroacoustic work composed by Roger Doyle. Different processing effects were applied to the sound of a horse’s galloping. As the soundtrack progresses, the sounds revert back to their original state. This is illustrated in the gradually appearing image of a horse. 

In a public performance of one of Roger Doyle’s works, the horse image appears gradually on a screen as the work is played. (The Ninth Set, Volume 3, Passades: A Passade is an  equestrian term meaning to move backwards and forwards over the same space.) See,  also, 

https://rogerdoyle1.bandcamp.com/album/the-ninth-set-passades-volume-3