Now I've stumbled upon different posts here and there around the web for extracting a still as a thumbnail for the video.. but I can't seem to find anything related to extracting a cover thumbnail of a video that has an existing image embedded into the video as it's thumbnail.
for mp3 it's as easy as:
ffmpeg -i "file.mp3" "file.jpg"
but it's a totally different story for mp4.
Any help would be very helpful. Thank you.