With pipewire-alsa Pipewire support applications that use ALSA directly and I can’t understand that.
ALSA is an sub-system of Linux kernel, part of the kernel, so applications use syscalls to communicate with ALSA. How can pipewire-alsa interfere to this? How userland process can interfere to syscalls by another process?
And if this is possible with ALSA, why can’t Pipewire do the same with V4L sub-system of the kernel?
Before I go further an important thing to be aware of here is that unlike on ALSA, where PipeWire can provide a virtual ALSA device to provide backwards compatibility with older applications using the ALSA API directly, there is no such option possible for v4l2