To play an MP4 file, use a video player like Windows Media Player or QuickTime. Other options include installing an MPEG-4 codec pack or converting the file into a playable file extension.
- Play the file
Right-click on the file, and select Play. Wait for the computer to open an application that supports the file extension. Supported applications include Windows Media Player, QuickTime and VLC.
- Install an MPEG-4 codec pack
If both the default and your favorite media players do not support the MP4 file, install an MPEG-4 codec pack, such as X Codec Pack, that allows the file type to be played on any media player. This is available online at Codecs.com. Use the download link on the codec pack's page to begin installation. Install the codec pack by using the Complete Mode for a simple and automatic installation process.
- Convert the file
To convert the MP4 file into another file format such as WMV, open the MP4 file using the file's default application. Locate the section of the application that allows such actions as Save As, and save the MP4 file as a different file extension. If the above method fails, use a video converter application, such as Any Video Converter or Freemake Video Converter, to convert the MP4 file into a different file extension.