Hello. I'm trying to compile ffmpeg for Win 8.1 accouridng this guide:  http://trac.ffmpeg.org/wiki/CompilationGuide/WinRT   but i have this problem: Also, i found out this guide: https://github.com/Microsoft/FFmpegInterop   But i take the same problem. "config.log" is attached to the mail. Hope. You will help with this problem. Thanks in advance. P.S. Maybe, do you have any compiled files for win8.1 or win phone 8.1?