crossfades

Crossfades are gradual transitions between two audio or video sources in which the outgoing signal fades out as the incoming signal fades in, overlapping in time to blend the two. This technique helps create smooth continuity and reduces abrupt cuts.

Historically, crossfades emerged with analog and tape-based mixing as a practical way to maintain seamless transitions between segments. In film and video editing, crossfades—often called dissolves—signal a change in scene or a passage of time. The term derives from the crossfader control on audio mixers, which blends two channels by sliding between them.

There are several forms of crossfades. In audio, a crossfade involves overlapping two audio clips with adjustable duration and a chosen fade curve. Common curves include linear, exponential, and logarithmic shapes, which affect how quickly the levels change and how the transient content is preserved. In video, a crossfade usually refers to a cross-dissolve where the image from one clip gradually overlays with the next, with changing opacity over the overlap window. Some editors distinguish more complex transitions, but the core idea remains a gradual blend rather than a hard cut.

Implementation is typically done in digital audio workstations and video editing software via automation, transition effects, or dedicated crossfade tools. Parameters to manage include overlap duration, curve shape, synchronization with tempo or motion, and potential artifacts such as phase issues in audio or visual discontinuities in video.

Crossfades are widely used to create mood, indicate time shifts, or preserve audio continuity, but may be avoided when a sharp, deliberate cut is desired. See also fades, dissolves, and transitions.