An AEP file is the primary project file format created by Adobe After Effects, a widely used digital visual effects, motion graphics, and compositing application. This file does not actually contain media assets like video clips, audio tracks, or images; instead, it stores the timeline, layers, keyframes, effects, composition settings, and references to all the external media files used in a project. Because it acts as a container for instructions rather than raw media, AEP files are relatively small in size until the project becomes extremely complex with thousands of layers and nested compositions. Motion designers and video editors rely on AEP files to build intricate animations, title sequences, visual effects for films, and broadcast graphics. When collaborating, professionals often need to collect and save the project along with all its dependent footage using the 'Collect Files' feature, as sending just the AEP file to another computer without the source assets will result in missing media warnings and broken project links.