I know that Telegram has abandoned the video call function, since it is impossible to implement secure video calls.
How did you manage to cope with security issues?
It is possible that this is solved using the blockchain. Nevertheless, while it is not known.
It is important that making a video call is as safe as a normal call.
blockchain is necessary for the functioning of its own token and for smart contracts (exchange of cryptocurrency and other deals)
Blockchain is not applicable for video calls