Clearify documentation about what pipewire gstreamer plugins can do and what not
From the existing documentation it is unclear what pipewiresrc and pipewiresink are capable of.
- is the (video) buffer transfer zero copy?
- can multiple srcs connect to the same sink?
- can sink and source be in different processes?
- can you run pipewiresrc and pipewiresink in virtual machines?
- is only dma supported or any other format, like (video) "raw" cpu buffers, or fd handles from nvbufsurfaces on nvidia jetson ?