Copy in this folder the compiled FFMPEG binaries.
You can download precompiled shared binaries from:
If you are on windows, you can download the latest 5.0 GPL binaries from the following link:
Extract the content of the bin folder in this folder.
You should end up with a folder that looks like this:
.gitignoreREADME.mdavcodec-59.dllavdevice-59.dllavfilter-8.dllavformat-59.dllavutil-57.dllpostproc-56.dllswresample-4.dllswscale-6.dll