Hi @suman_kumar_dey,
Indeed, the Kaltura Server does not work correctly with MySQL 5.7 due to changes made to the strict mode mechanism. Before you run the installation script, you must purge all MySQL packages from the official Ubuntu repos and only then install the Percona 5.5 packages as stated in the howto.
So, first:
# apt purge mysql-client mysql-server
Then, just to make certain, run:
# dpkg -l "*mysql*"|grep ii
Which should return nothing. Then deploy the Percona packages as per the guide and then run the Kaltura installation script.