I know it's possible with FFMPEG, but what to do if I have a partial file (like without the beginning and the end). Is is possible to extract some frames from it?
The command
ffmpeg -ss 00:00:25 -t 00:00:00.04 -i YOURMOVIE.MP4 -r 25.0 YOURIMAGE%4d.jpg
will extract frames
Check you movie for the framerate before applying option [-r], same applicable for [-t], unless you want to extract the frames with the custom rate.
Never tried this with the cropped (corrupted?) input file though. Worth to try.