Video capture is something that's "just worked" for me for as long as I can remember (unlike audio). What's the value gained from the added latency of an intermediary? Is it only to ease containerization?
I think this is also key for getting libcamera in the mix.
And pipewire is phenomenal, I assume this opens the door for video transformations, a+v effects, etc. I'm quite excited about it.
People have been using a out of tree loopback video kernel driver for these things which is hard to use and hacky and slow.
So you end up with a bunch of kernel interfaces for hardware-accelerated video transforms (many driver-specific), a few competing userspace APIs (gstreamer, vulkan extensions, vaapi, vdpau, etc), zero-copy kernel buffer APIs, the list goes on. You end up with something like Pipewire just to abstract over the complexity.