Documentation needed - please :-)

[mORogyrUly]

I need more information how to use the wrapper in more different situations. For example I want to convert every frame from a video to a single picture. As a workaround i use the ffmpeg direct with the process.start("ffmpeg"," -i inputfile.mp4 -o output.bmp") (macOS) but I know this procedure works on windows, too. Thank you.