1. Is video calling safe
2. are there any chances of some other persons hacking of my private video chat
1. Yes. Totally safe if it is a Skype-to-Skype call.
2. No. All Skype-to-Skype calls are fully encrypted.
just to add up, having a fully updated, trusted, and reliable anti-virus/firewall would also keep your account and conversations much more secured.