Summary: It's impossible to import MP4 to Windows Movie Maker. If you want to edit MP4 in WMM, you have to convert MP4 to Windows Movie Maker compatible format.
Source:How to Get Windows Movie Maker recognize my MP4 movies
As a free and famous video editing software, Windows Movie Maker has the ability to create and edit videos and then upload them to YouTube, Facebook and Flickr etc for sharing. However, just like other editing systems, it has no ability to handle all video formats. And you will find a painful experience to import MP4 movie files into Windows Movie Maker for further editing. Fortunately, there is an easy way to fix this issue. Let's find it out here.
Since the MP4 codec is a final delivery codec it is not one you want to use for editing. Therefore the easy workaround is to convert MP4 to a more editing-friendly format, such a Windows Movie Maker's WMV.
For transcoding MP4, the best program I can recommend is Brorsoft Video Converter. It's an easy-to-use yet powerful high-quality video converter, player and editor. And it can handle videos in all formats, including MP4 format and make them best suitable for Windows Movie Maker quickly and easily. What’s more, this app also provides some cool video editing features like cropping, cutting, merging and so on. So no doubt, this powerful Windows Movie Maker video converter will bring you an extraordinary video-editing experience. If you are facing problems when editing video footages with Windows Movie Maker, Avid MC, Vegas Pro, Premiere Pro, Pinnacle etc. non-linear editing systems, chances are you already installed this great free utility. If not, download it it from here.
So, how to convert MP4 files for editing in Windows Movie Maker? Below is how.
1) Launch the MP4 to Windows Movie Maker Converter, and then import MP4 clips through "Add Video" button or "Add from folder" button.
2) Hit the Format box and select HD Video -->WMV HD(*.wmv) on the dropdown menu as output format. Besides, you can also choose Divx HD(*.avi) as output if you have not installed the .wmv codec.
3) You can adjust video and audio parameters, including the Bitrate of Video and Audio, the Codec of Video and Audio, Video Size, Sample Rate, Frame Rate, Audio Channels, etc., in the Profile Settings.
4) When everything is OK, press "Convert" to start MP4 to Windows Movie Maker converison.
Once the process completes, simply click "Open" button and you can locate the result videos ready to be imported to Windows Movie Maker for further editing.
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