If you ever ran across the issue that VisualStudio wants to re-build your project every time you hit F5
then the steps described here might be helpful.
At least in my case, it immediately spit out this line
 Project 'S:\DEV\Projects\Video\ffmpeg\WINFFMPEG\Solution\ffmpeg\ffmpeg.vcxproj' not up to date because build input 'S:\DEV\PROJECTS\VIDEO\FFMPEG\WINFFMPEG\SOLUTION\FFMPEG\INTTYPES.H' is missing.
which pointed my directly to the culprit.