ffmpeg screenshot native resolution
apply chmod x to mediashot
chmod +x mediashot
install mediainfo and ffmpeg
apt-get install mediainfo
wget http://johnvansickle.com/ffmpeg/releases/ffmpeg-2.4.3-64bit-static.tar.xz
tar xfv ffmpeg-2.4.3-64bit-static.tar.xz
cp /home/user/ffmpeg-2.4.3-64bit-static.tar.xz/ffmpeg /usr/bin/
cp /home/user/mediashot /usr/bin/
mediashot [your video file] [newfolder] [name of your video]
mediashot example.mkv example-screenshots example