An AEP file is normally used as an After Effects project definition that contains the instructions for building your composition rather than a finished movie, including timelines, multiple layer types, animation data like keyframes, effect parameters, masks, mattes, and 3D components such as cameras and lights, while referencing external media files to stay tiny even if the project uses gigabytes of footage.
Since the AEP relies on external links, After Effects may report “footage not found” whenever source files get moved, renamed, or omitted during a transfer, which is why the Collect Files feature (or manually assembling the AEP and all used media) is the normal way to send a project reliably, and if an AEP refuses to open in After Effects, hints like its source, companion files, Windows associations, or a quick read-only text-editor view can indicate whether it’s truly an AE project or an unrelated format.
When an AEP behaves like it’s broken on a different computer, the root cause is usually that it’s designed to reference files stored elsewhere, not contain them, with After Effects recording absolute paths to video, images, audio, and proxies, so the moment the project exists on a machine with new drive letters, renamed folders, or missing assets, AE loads the project shell but reports Missing/Offline Media until you relink all sources.
A project may appear not loading correctly despite having the footage if the new system is missing fonts—leading to text reflow—or third-party plugins—causing effects to show as missing—or if an outdated After Effects version can’t process newer features, and the reliable remedy is to transfer via Collect Files or copy everything exactly as-is, then relink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 is a compressed structural database for AE so it can store an entire motion-graphics workflow while staying tiny, preserving comp settings—resolution, fps, duration, background, nesting—and all layers with transforms such as placement settings, scale, rotation, opacity, blend modes, mattes, parenting, timing, plus everything related to animation: keyframes, easing, motion blur, markers, and expressions, along with the full effect chain and mask/roto elements including mask paths, feather, expansion, and animated vertices.
If you enable 3D features, the AEP keeps your cameras, lights, 3D-layer properties, and render-related settings, plus organizational details like bins, label colors, footage interpretations, and sometimes proxies, but it usually leaves out the actual media—your MP4s, MOVs, images, and WAVs stay on disk—so the file mainly stores the recipe for how everything works and the addresses of your source files, which is why moving or renaming footage triggers missing-media prompts until you relink If you have any sort of inquiries regarding where and ways to make use of file extension AEP, you can call us at our own web-page. .
