If you have an issue with the bandwidth consumed by facebook users in your network, but you still have to allow them to use it, this trick might help you.
Goal: Block facebook videos but allow rest of the content to be displayed
Solution:
Go to IP → DNS → Static
Hit the ‘+’ button
Input as follows:
Name: leave it blank
Regexp: “.video..fbcdn.net.*” (without the quotes)
Address: use any address you know will not resolve like 127.0.0.1
TTL: leave default value.
Save it.
Now go to IP → DNS → Cache and hit the button “Flush Cache” at the left top, this will force the new request to be evaluated and if one comes from facebook it will block that content.
At user level they will not notice anything, the video will never load.
After a couple of hours of try and error I was able to come up with this, so I hope this helps someone as it helped me,