Install ffmpeg prebuilt binaries.
$ npm i --save ffmpeg-prebuilt$ node
> require('ffmpeg-prebuilt');
{ ffserver: '/Users/poying/Workspace/node/ffmpeg-prebuilt/files/ffserver',
ffprobe: '/Users/poying/Workspace/node/ffmpeg-prebuilt/files/ffprobe',
ffmpeg: '/Users/poying/Workspace/node/ffmpeg-prebuilt/files/ffmpeg' }