Preparation
http://www.ffmpeg.org/download.html
https://github.com/yuvi/gas-preprocessor
https://github.com/kewlbear/FFmpeg-iOS-build-script
References
- http://al1020119.github.io/blog/2016/01/11/ffmpeg-kxmovies/
- http://www.liuxiao.org/2015/08/ios-ffmpeg-%E8%A7%86%E9%A2%91%E8%A7%A3%E7%A0%81%E5%BA%93%E7%9A%84-ios-%E7%89%88%E6%9C%AC%E7%BC%96%E8%AF%91%E5%92%8C-kxmovie-%E6%92%AD%E6%94%BE%E5%99%A8/