How can i stop a shared file (video files and pictures) being copied by the recipient?

you can save them to a website and protect the content, but then if you are sending them because you want the person to look at them, they can still take a screen shot of them. if thats ok, then use a file sharing service that protects them for you and just send a sharing link. There are so many you have to decide what it is that you want.

You can't stop the recipient from copying them and sending them on or using them but you can put a watermark on them and tell whoever you send them to they are copyrighted and not to be copied or used without your permission. Keep a copy of that message and if they are copied and used without your permission then you have a legal standing to do something.

Ron

No. You cannot. You may add a password to the pdf but the recipient will still know the password.