Note :- use www.facebook.com instead of m.facebook.com to download the videos.
Facebook Mp4 Videos Downloader
[Steps] FBMp4 To Save FB To Mp4 :-
1. Go to facebook and open the video which you want to download. Tap on (...) & copy link.
2. Now, paste the facebook video link in above input box, and simply hit Enter.
3. Your fbmp4 SD & HD video download links will appear.
4. Just click to get the fb video and save the mp4 file in your device.