The bouncing ball is a virtual device used in motion picture films and video recordings to visually indicate the rhythm of a song, helping audiences to sing along with live or prerecorded music. As the song's lyrics are displayed on the screen in a lower third of projected or character-generated text, an animated ball bounces across the top of the words, landing on each syllable when it is to be sung.
The bouncing ball is mainly used for English language songs in video recordings, however, in Japan, a similar device is used where the text changes color as it is sung, just like in karaoke.