Windows Movie Maker is very slow in converting from MP4 to whatever it's using as its preferred/interim format. What is their preferred format, so I can convert to it using faster and/or GPU accelerated programs?

I've somewhat ruled out WMV, however, I converted the video to it, and WMM is processing it a good amount faster.

What is the ideal format to use for movie maker for importing video?

55 hours of video to encode/process with microsoft "technology" is not fun!

  • Please retag this, I can't create the tag "windows-movie-maker", which would be most appropriate. Dec 22, 2013 at 2:12
  • To the close vote: this is not opinion based. Most probably Windows Movie Maker has a preferred format which doesn't need any transcoding by WMM. Dec 23, 2013 at 12:42
  • Which version of movie maker? It appears it may make a difference.
    – AJ Henderson
    Jun 15, 2014 at 20:41
  • @AJHenderson 2012 Jun 15, 2014 at 23:14

2 Answers 2


Windows Movie Maker, being a Microsoft product, works with WMV files using the Windows Media Video codecs. You can use the free Windows Media Encoder to encode the files. I believe there is also a free version of Microsoft Expression Encoder that you could use as well. Expression is a bit newer, but slightly less capable since they moved a lot of functionality to the commercial Expression Encoder Pro (the Pro version is unfortunately not free).


Poking around in the cache files, it appears that its ideal format is actually MP4. This matches my observations on CPU usage when using a non-mp4 format.

  • Prior to windows 7, WMM didn't even have MPEG-4 support without third party codecs. It is rather unlikely that MP4 is the prefered codec. More likely, you are seeing reduced CPU usage on MP4 because they may be using GPU decoding capabilities for MP4 since MP4 is a more broadly used standard than WMV. The MS materials for WMM list WMV first and this makes sense as WMV is Microsoft's video format.
    – AJ Henderson
    Jun 13, 2014 at 4:37
  • But that's not the case. The cache files in appdata are all mp4. Jun 15, 2014 at 19:42

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