no instance of overloaded function "std::make_unique" matches the argument list, but works with unique_ptr constructor

What's happening?

Unfortunately, std::make_unique can't specify the deleter type. Its 2nd template parameter is used for the type of the list of arguments passed to it. The code fails because you specify it as AVFrameDeleter explicitly, but pass AVFrame*, they don't match.

Unlike std::make_shared (which has std::allocate_shared), std::make_unique does not have an allocator-aware counterpart. A hypothetical allocate_unique would be required to invent the deleter type D for the unique_ptr<T,D> it returns which would contain an allocator object and invoke both destroy and deallocate in its operator().

On the other hand, the following code works (even it's not what you expect).

// the 1st template parameter is specified as AVFrame
// the 2nd template parameter is deduced as {AVFrame*}
// construct a std::unique_ptr<AVFrame, std::default_delete<AVFrame>>
std::make_unique<AVFrame>(av_frame_alloc());