fade-in
US /ˈfeɪd.ɪn/
UK /ˈfeɪd.ɪn/

1.
fade-in, entrada gradual
a gradual increase in the visibility of an image or the volume of a sound in a film, television, or radio production
:
•
The scene began with a slow fade-in of the sunrise.
A cena começou com um lento fade-in do nascer do sol.
•
We need a smooth fade-in for the background music.
Precisamos de um fade-in suave para a música de fundo.