How to Download Codecs for Windows Movie Maker

By James T Wood

"Codec" is short for coding and decoding. It refers to the algorithm used to encode and compress digital audio and music and then decode it on playback. Encoded media files are typically smaller in size than unencoded files, but if Windows Movie Maker doesn't know the codec used to encode the file to begin with, it won't be able to read it. Windows stores all media codecs in one place, so you can install a codec pack that will allow Windows Media Player, Windows Movie Maker and any other media players on the computer to decode media files.

Step 1

Close down Windows Movie Maker. Save your project first, if necessary. Close any other media players that are open.

Step 2

Open a Web browser and browse to the download site for a codec pack. Some codec packs encompass many types of encoding, such as the "Windows Essentials Media Codec Pack" available at or the "K-Lite Codec Pack" found at Other codec packs will address specific codecs that you might need to play a particular file type, such as the "Windows Media Player" codecs available from

Step 3

Double-click on the downloaded file to begin installing the codec(s). Follow the onscreen instructions to complete the installation.

Step 4

Reopen Windows Movie Maker and attempt to add the video clip. The codec should be accessed correctly. If not, restart the computer and try again.

Tips & Warnings

  • Media players often come with codec packs included. Updating Windows Media Player or downloading a media player like Quicktime or the VLC media player might provide the codecs you need.
  • Only download files from trusted sources. Malicious software can be disguised as a codec pack.