New Delhi, Nov. 11 -- A movie ticket buys a seat, not a pause button. Leave for the bathroom at the wrong moment and a character can disappear, a relationship can change or a quiet conversation can turn out to be the scene that explains the ending.

a short window in which leaving the auditorium should cost the viewer as little as possible. Its app identifies bathroom-break opportunities, gives an on-screen cue for when to go and supplies a synopsis of what happens during the absence. It also tells users whether there is something to stay for after the credits.

The unusual part is how those windows are chosen. According to RunPee, a person watches the entire film in a cinema and takes notes. The company says neither an algorithm nor arti...