What resources are needed to run applications like Skype (audio and video calls + chat)?

Question

Mobile development

We are talking about financial, technical, etc. resources. Desirable in detail. Thank you.

Answer 1

In detail, this is the task, and the task is already work))) and even if the work is right off the bat, no one will tell you the number.
In short, it's expensive ... very.
Without a working solution, at least you can’t calculate the prototype in any way.