std::initializer_list conversion in constructors

I'm new to C++11 and I was wondering how this code works internally:

class MyClass
{
    public:
        MyClass(int a, double b) {
            cout << "ctor()" << endl;
        }
};

int main()
{
    MyClass i1{4, 7};
    return 0;
}

My understanding of the new initializer list is that it is a class std::initializer_list constructed by special syntax { .... } in the code. So how does this class instance created by {4, 7} internally get transformed to a form that fits the constructor to MyClass? Thanks.