[dvbviewer] fix possible crash

> The parameter parmN is the identifier of the rightmost parameter in the
> variable parameter list of the function definition (the one just before
> the ...). If the parameter parmN is declared with a function, array, or
> reference type, or with a type that is not compatible with the type that
> results when passing an argument for which there is no parameter, the
> behavior is undefined.
[dvbviewer] avoid an unnecessary copy

push to vector early and use back reference for filling the object