An AEP file is typically an After Effects project blueprint that stores the structure of your work rather than a finished video, holding compositions, layers of all kinds, animation data like keyframes and expressions, effects with settings, masks, mattes, and even 3D tools such as cameras and lights, while usually referencing external media through file paths instead of embedding footage, which keeps the AEP itself compact even when the project uses huge amounts of video or audio.

Since the AEP relies on external links, After Effects may report "offline footage" 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 loads but shows no media 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.

If you loved this write-up and you would like to obtain even more details concerning AEP file unknown format kindly check out our own website. Projects may look incorrect even when footage is present if the new computer lacks the proper fonts—causing text to substitute—or is missing third-party plugins, which makes certain effects show as unavailable, or if you open the file in an older After Effects version that can’t interpret newer features, and the dependable fix is to move the AEP using Collect Files or copy the full project structure exactly, then relink footage so that once fonts, plugins, and paths match, the project usually fixes itself immediately.

An AEP file functions as a lightweight database of project structure 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 shape paths, feather, expansion, and animated vertices.

Using 3D in AE means the AEP saves your cameras, lights, 3D-layer attributes, and render settings, plus project-structure info like bins, label coloring, interpretation settings, and proxy references, but not the source media itself—videos, stills, and audio live outside the project—so the AEP acts as the blueprint and the addresses for your assets, which is why moving or renaming them leads to missing-media notices until you relink.