A segment is a timed piece of media used by segmented streaming systems. A playlist or manifest tells the player where to obtain the pieces and how they fit into the presentation. Segment length, encoding and availability influence startup, seeking, quality switching and the amount of content a player can hold ahead.
A practical example
Instead of fetching a two-hour film as one immediate download, a player requests successive media pieces while playback proceeds. It may request another quality for later pieces when the presentation supports switching and delivery conditions change during the session.
A common misunderstanding
Do not assume that a segment is a single video frame or that every stream uses the same segment length. Audio and video arrangements also vary between delivery formats.
Related terms
Stable technical definition. Editorial approach