How i can remove or replace logo in video stream with FFmpeg

[sarjukhe]

Hi guys
I have a questions
How i can remove or replace logo in video stream with FFmpeg?
For example: this link
http://82.102.10.147/720P - 1.mkv
As you can see at the bottom and top of the logo (gemonline)
Now this:
http://82.102.10.147/720P - 2.mkv
As you can see logos replaced! With (moviebaz)

Source video:
https://goo.gl/5rfloy

But for see, first you need to login (you can use my user and password)
user: gemonlinetest1@gmail.com
pass: 12345678

I konw he uses FFmpeg for this, but how ????

if you know any sotware or any way for this, please help me!!!