The media cache

When After Effects imports video and audio in some formats, it processes and caches versions of these items that it can readily access when generating previews. Imported audio files are each conformed to a new .cfa file, and MPEG files are indexed to a new .mpgindex file. The media cache greatly improves performance for previews, because the video and audio items do not need to be reprocessed for each preview.

Note: When you first import a file, you may experience a delay while the media is being processed and cached.

A database retains links to each of the cached media files. This media cache database is shared with Adobe Premiere Pro, Adobe Encore, and Adobe Soundbooth, so each of these applications can each read from and write to the same set of cached media files. If you change the location of the database from within any of these applications, the location is updated for the other applications, too. Each application can use its own cache folder, but the same database keeps track of them all.

 Choose Edit > Preferences > Media & Disk Cache (Windows) or After Effects > Preferences > Media & Disk Cache (Mac OS), and do one of the following:

  • Click one of the Choose Folder buttons to change the location of the media cache database or the media cache itself.

  • Click Clean Database & Cache to remove conformed and indexed files from the cache and to remove their entries from the database. This command only removes files associated with footage items for which the source file is no longer available.

    Important: Before clicking the Clean Database & Cache button, make sure that any storage devices that contain your currently used source media are connected to your computer. If footage is determined to be missing because the storage device on which it is located is not connected, the associated files in the media cache will be removed. This removal results in the need to reconform or re-index the footage when you attempt to use the footage later.
Cleaning the database and cache with the Clean Database & Cache button does not remove files that are associated with footage items for which the source files are still available. To manually remove conformed files and index files, navigate to the media cache folder and delete the files. The location of the media cache folder is shown in the Conformed Media Cache preferences. If the path is truncated, click the Choose Folder button to show the path.