What is the main purpose of the 'timeline' in a video editing app, where you put all your video clips and sounds?

The main purpose of the 'timeline' in a video editing app is to serve as the central workspace where all media elements of a video project are chronologically arranged, synchronized, and precisely timed to create the final edited sequence. It provides a visual, linear representation of the entire film or video, moving from left to right to signify the progression of time.

On the timeline, individual media files, referred to as "clips" (including video footage, audio recordings, still images, and graphics), are placed onto separate horizontal sections called "tracks" or "layers." For example, video clips reside on video tracks, while sound elements like dialogue, music, and sound effects are placed on distinct audio tracks. This layering allows multiple elements to play concurrently, such as music playing beneath dialogue or a text overlay appearing on top of a video.

Users manipulate these clips directly on the timeline by dragging them to establish their desired chronological order, a process known as "sequencing." Editors also precisely control the duration of each clip by "trimming" its start and end points. "Synchronization" is performed to align audio with corresponding video, ensuring, for instance, that dialogue matches character lip movements. The timeline's non-linear editing capability means any segment of the sequence can be modified, removed, or reordered at any point without altering the original source media files or affecting other parts of the project, thus offering complete flexibility.