Question: What is an MP4 File?
Did you find an MP4 file on your computer and wonder what program should open it? Maybe someone emailed you an MP4 file but you're not sure how to use it. Perhaps you tried to open the MP4 file but Windows told you that it could not open it.
Before you can open an MP4 file (assuming it's even a file format that's intended to be viewed or edited), you'll need to determine what kind of file the .MP4 file extension refers to.
Answer: A file with the MP4 file extension is an MPEG-4 Video file.
Other types of files may also use the MP4 file extension. If you know of any additional file formats that use the .MP4 extension, please let me know so I can update this information.
How To Open an MP4 File
The easiest way to open an MP4 file is to double-click on it and let your PC decide which default application should open the file. If no program opens the MP4 file then you probably don't have an application installed that can view and/or edit MP4 files.
Warning: Take great care when opening executable file formats received via email or downloaded from websites you're not familiar with. See my List of Executable File Extensions for a listing of file extensions to avoid and why.
Important: If you find that your favorite video player doesn't open MP4 files, you may need to install an MPEG-4 codec. An MPEG-4 codec is a small piece of software that allows your computer to recognize MP4 files and have them play properly in whatever player you use.
I highly recommend XP Codec Pack, a completely free collection of popular codecs that works in Windows 8, Windows 7, Windows Vista, and Windows XP. After installation, you'll be able to play MP4, as well as almost all other popular video formats, in your favorite player. Just watch out for the ads on that XP Codec Pack site - they can look deceivingly like download links!
If you know of any other program that can open or edit MP4 files, or you know anything else useful about MP4 files, please let me know so I can update this page.
If you find that an application on your PC does try to open the MP4 file but it's the wrong application, or if you would rather have another installed program open MP4 files, see How To Change the Default Program for a Specific File Extension for instructions on making that change in Windows.
How To Convert an MP4 File
There are two main ways to attempt to convert an MP4 file to another file type:
- Open the MP4 file in its default program and choose to save the open file as another file format.
- Use a File Conversion Online Service or Software Program to convert the MP4 file to another file format.
The first option involving opening the MP4 file in its native program is preferable because it's both easier and will probably result in a more accurate file conversion. Of course if you don't have a program that opens MP4 files, a third-party file conversion tool (the second option) could be very useful.
Important: You cannot usually change a file extension (like the MP4 file extension) to one that your computer recognizes and expect the newly renamed file to be usable. An actual file format conversion using one of the methods described above must take place in most cases.
Still Having Problems Opening or Using an MP4 File?
See Get More Help for information about contacting me on social networks or via email, posting on tech support forums, and more. Let me know what kinds of problems you're having with opening or using the MP4 file and I'll see what I can do to help.