Why my tv screen freezes every 5 seconds

Model: Sony Bravia KDL - 47W804A

The tv was working fine earlier, we are using youtube that time then the tv screen suddenly freezes in 3 seconds with a horizontal line above then after that the screen then working again, but it repeatedly doing that, every 5 seconds.

It Freezes then works again freezes and working again

How to fix this problem? We tried unpluging it for an hour and doing a factory reset and it still doesnt works.