get ffmpeg and use this code in command prompt from your downloads (type cmd in the searchbar when AT the downloads page):
ffmpeg -i VIDEO.mp4 -r FPS frame%d.png
VIDEO is changed to the name of the file for the video, FPS is changed to whatever fps you want, even to things like 0.25fps! You can also change the extensions of the files (.mp4 and .png) to whatever fits.