An AEP file represents an AE project definition that outlines how your video is built rather than producing a playable export, capturing compositions, Layer elements of all types, animation data such as expression-driven actions, effect setups, masks, mattes, plus cameras and lights in 3D space, and since it usually references media instead of embedding it, the AEP stays compact even when the project draws on large external assets.
Because AEP projects depend on external file paths, moving or renaming sources—or copying only the AEP to another system—can trigger “media missing” errors, making the Collect Files workflow (or a manual folder gather) the usual method to keep everything linked, and if an AEP doesn’t open correctly, factors like where it came from, what files accompany it, what Windows says under “Opens with,” or a brief text-editor inspection can help identify whether it’s an authentic AE project or a separate vendor’s format.
When an AEP loads without footage on a second computer, the reason is usually that it’s a blueprint referencing outside media instead of embedding it, and After Effects uses absolute file paths for video, images, audio, and proxies, so once the project is moved to a machine with mismatched paths—different drives, folder names, or missing files—AE can load the structure but not the assets, yielding Missing/Offline Media until relinking.
A project may appear “broken” despite having the footage if the new system is missing fonts—leading to text substitution—or third-party plugins—causing effects to show as missing—or if an outdated After Effects version can’t process newer features, and the reliable remedy is to transfer via Collect Files or copy everything exactly as-is, then relink footage so that once fonts, plugins, and file paths align, the project usually resolves itself immediately.
An AEP file acts as a compact database for your After Effects project, which is why it can store an entire motion-graphics setup without matching the size of your footage, capturing details about comps—their resolution, frame rate, duration, nesting, and background—along with every timeline layer and its transforms such as X/Y/Z coordinates, scale, rotation, opacity, blend modes, mattes, parenting, and timing, plus animation elements including keyframes, easing, motion-blur settings, markers, expressions, and full effect setups, as well as masks or roto shapes with their paths, feather, expansion, and animated points.
When you use 3D tools, an AEP stores your camera setups, lighting, all 3D-layer attributes, and any render settings tied to them, along with project-organization info like folders, label colors, interpretation rules, and sometimes proxy links, but it generally doesn’t embed media—MP4s, MOVs, images, and WAVs remain separate—so the AEP holds the project logic and the location references of the sources, causing missing-media alerts if items are moved or renamed If you loved this article and you would such as to receive additional details regarding AEP file structure kindly check out our website. .
