ah found it, it's a vault of audio if anyone else is curious.

I've had the idea for a while that it should be possible to have an app listen to the movie audio and synchronise the AD track automatically. I think I even heard of such an app but it wasn't open and I haven't heard about it since.

Almost every time I watch something with my family I wish that the AD could be separate so we can listen at a normal volume without the boomy describer's voice which is almost always far too loud.