# pipewire-pulse, the PulseAudio protocol on top of PipeWire, for clients that
# speak nothing else. Wine's audio driver is one of them.
#
# The socket moves out of the service user's runtime directory. That directory
# is 0700 and the workload runs as a different user, so a client there finds
# nothing and plays silently, which is the failure PipeWire's own socket was
# moved for. The workload is pointed here with PULSE_SERVER, and nesinit starts
# this under a umask that lets a user who does not own the socket open it. This
# path is written in nesinit too, and a test there compares the two.
#
# A drop-in replaces a key of pulse.properties rather than appending to it, so
# the default "unix:native" socket is not created as well.
pulse.properties = {
    server.address = [ "unix:/run/pipewire/pulse-native" ]

    # module-always-sink creates a "Dummy Output" sink whenever no other sink
    # exists, and while neswire's sink is not up yet that is always. A second
    # sink is a second default-node candidate, and a game that picks it plays
    # into nothing. neswire has to be the only sink; see the WirePlumber
    # drop-in.
    pulse.cmd.always-sink = false

    # The root is read-only and every box starts from the same image, so there
    # is nothing to restore and nowhere to save, which is the reasoning behind
    # turning off WirePlumber's state hooks. Left on, these are one more place
    # that could pin a default.
    pulse.cmd.device-manager = false
    pulse.cmd.device-restore = false
    pulse.cmd.stream-restore = false

    # Wine sizes its whole audio path from this number. At startup its driver
    # opens a probe stream asking for a 1-frame request size, reads back what
    # the server grants, which is this floor, and makes the device period ten
    # times that. Streams then queue three periods. The default floor of 256
    # frames therefore becomes a 53 ms period and about 160 ms of audio in
    # flight, which is desktop playback and not a game being streamed.
    #
    # 48 frames (1 ms) makes that period 10 ms, the default period Windows
    # itself uses, so a game gets the buffering it was written for. A stream
    # then asks for 480-frame requests, which is what is granted, so the floor
    # affects the probe and nothing else Wine does.
    pulse.min.req = 48/48000

    # What a client gets when it asks for no particular buffering. The shipped
    # default is two seconds, which is only harmless where nobody is listening
    # live. 10 ms requests and 40 ms of target buffer are enough for a client
    # that does not say.
    pulse.default.req = 480/48000
    pulse.default.tlength = 1920/48000
}

# pipewire-pulse.conf raises the minimum node latency to 1024 frames (21.3 ms)
# inside a virtual machine, which a box is. That puts every Pulse client, and
# therefore Wine, at least 21 ms behind, whatever it asked for. Floor it where
# the graph itself is floored instead; see the pipewire.conf drop-in for why
# 256 frames. A drop-in appends to this array, and every matching rule applies
# in order, so this runs after the shipped rule and wins.
pulse.properties.rules = [
    {   matches = [ { cpu.vm.name = !null } ]
        actions = {
            update-props = {
                pulse.min.quantum = 256/48000
            }
        }
    }
]