I have been trying to figure out a way to build OpenCV_FFMPEG.dll on my own. This is necessary to customize the FFMPEG build according to my requirements rather than going with FFMPEG library(OpenCV_FFMpeg) downloaded by OpenCV.
The closest post I found which tried explaining how to build OpenCV_FFMPEF.dll was this: http://answers.opencv.org/question/124858/how-to-build-opencv_ffmpegdll-from-patched-ffmpeg-source/
Even that post is outdated and I get a plethora of linker errors and duplicate symbols when I followed the instructions. Can anyhow help me how to build the library? More interesting why is this not documented anywhere?