My process for editing GoPro Hero 2 MP4 files (1920x1080) starts with GoPro Studio removing the fisheye effect, compressing to an AVI file using the GoPro provided CineForm 10-bit Visually Perfect HD Codec.

I then use Movie Maker (version 2012, 2.6 or 6.0) to produce an MP4 or WMV file from the AVI.

On Windows 8.1 the process works perfectly and the finished videos (usually about 10 minutes in duration) play well. 

The same process on Windows 10 ends up with MP4 or WMV files (of any quality setting) that play fine for the first 2-1/4 minutes; beyond that the audio keeps going to the end, but the visual is just blackness.  There's a setting of some kind that stops the visual stream from encoding beyond the 2-1/4 minute mark. Thanks for any suggestions.