How to Open MP4 Videosby Andrew Meer
MPEG-4, commonly known as MP4, is a type of file format used to store compressed audio and video streams. You can open MP4 videos by using Windows Media Player 12, which is a multimedia application that comes along with Windows 7. Windows Media Player 12 comes built-in with the MPEG-4 codec, so you will not need to download and install any additional software.
Open Windows Media Player 12 by clicking "Start," click "All Programs" and then clicking "Windows Media Player."
Press the "Ctrl" and "O" keys together to open the "Open File" dialog box.
Use the navigation pane inside the "Open File" dialog box to select the MP4 video that you want to open.
Click "Open" to open the MP4 video in Windows Media Player.