We will do our operations for the default group, you can edit it by adding a new group or for a different group.
Click on Settings->Web Filtering menu on the interface screen.
From the screen that opens, click on the Group_default definition that we previously defined for the default group.
Here we type video in the search field and select the relevant category as Blocked as in the image.
After saying Save, we go to the Settings->Group Management menu.
Here we click on the default group and go to the Port Blocking tab.
We check the Radio/Video Streaming option and click save.
You can test it for your default users.