Can't get &mut gst::BufferRef from &mut gst_video::VideoFrameRef

In VideoFilterImpl::transform_frame_ip I get a &mut gst_video::VideoFrameRef<&mut gst::BufferRef> to modify, but I need to be able to add custom meta to the underlying &mut gst::BufferRef.

As I wrote on Matrix:

you can get a pointer to the GstVideoFrame C struct and that has the buffer pointer

actually not sure if we can provide safe API for that. you would be able to invalidate the mapped frame nothing prevents you from just removing all the memories from the buffer, for example

adding a meta is fine though, just have to be a bit careful

So I guess if we want to avoid unsafe, we would have to add API to VideoFrameRef for everything that doesn't touch memory?

I guess I'd be happy with a unsafe fn buffer_mut(&mut self) -> &mut BufferRef.

That can be added and you can also easily do that yourself already from the outside until it's added to the bindings :)

You want to create an MR?

I'll also need that soon so I'll add it if you're not faster :)