An AEP file is a project file created by Adobe After Effects, a professional video editing and motion graphics software. It contains all the elements of a video project, including footage, compositions, layers, effects, audio, and timelines. The AEP file itself doesn't contain the actual video or audio data; instead, it stores references to these external files. This allows for non-destructive editing, meaning the original source files remain untouched. Opening an AEP file in After Effects allows users to modify and render the project into a final video format like MP4, MOV, or AVI. AEP files are essential for collaborative workflows, allowing multiple editors to work on the same project. They also enable users to save and reuse complex animations and effects across different projects. The AEP format is proprietary to Adobe After Effects and requires the software to be opened and edited.