Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/7432>
We were using global default allocator already. Pass null allocator object to *_alloc() methods then the method will use default allocator. Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/2843>
An example to demonstrate color space conversion, rescale and flip/rotation using GstD3D11Converter Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/2767>