Copyright is a creation of law in each country, and therefore there is no such thing as an international copyright law that will protect an author/artist's work throughout the world with a single registration.
Although there is an international copyright treaty known as The Berne Convention for the Protection of Literary and Artistic Works which is the most important international treaty that addresses international protection for copyright(Both India and Bangladesh are signatories to the Berne Convention)
The Berne Convention, states that once a work is protected in one of the Convention member countries, it is protected by copyright in all of them.
The Berne Convention further says that the scope and limitations of any copyright are based on the laws of the country where the misuse of the copyright-protected work takes place (rather than the country where the work originated).