So this has been something which has been winding me up for the last 6 hours.

I've got a movie which is a few clips trimmed and placed together, very simple.

I'm talking in the video so it's really important the timing of these trimmed clips is exact. It's exactly as I'd like it in the project file of movie maker. 

However, the problem arises when I save the file and it gets exported. In the resulting .mp4 the beginning is cut off and various other points which are clipped are changed, with certain parts running too long and other parts stopping abruptly.

I've tried saving and re-saving this through various different settings and playing round copying new clips in etc, but nothing's working.

I'm looking to upload this to YouTube and the standard it's at when it's saved is just awful. Anyone got any ideas why the exported file is different to the project video?