What does a fade-in transition signify in video editing?

A fade-in transition is a common technique used in video editing to signal the beginning of a new scene. It typically starts with a black screen that gradually brightens to reveal the visuals as the scene increases in visibility. This method not only prepares the audience for a shift in the narrative but also helps to set the tone for what is about to unfold. By transitioning from darkness to light, it effectively captures the viewer's attention and indicates a clear start to a new segment of the video.

The other options reflect different editing techniques or concepts that do not align with the purpose of a fade-in transition. For example, ending a scene would utilize a fade-out rather than a fade-in. Changing an audio track relates to sound editing rather than visual transitions, and a sudden cut between scenes implies an abrupt change rather than a gradual introduction, which is contrary to the smooth nature of a fade-in.