feat: media bitrate control, HDR (#346)

Fixes: #335 

Still a work-in-progress.

---------

Co-authored-by: DatCaptainHorse <DatCaptainHorse@users.noreply.github.com>
Co-authored-by: Claude Opus 5 <noreply@anthropic.com>
Co-authored-by: Wanjohi <elviswanjohi47@gmail.com>

build/etc/pipewire/pipewire-pulse.conf.d/50-nestri.conf

@@ -0,0 +1,66 @@
+# 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
+            }
+        }
+    }
+]

build/etc/pipewire/pipewire.conf.d/50-nestri.conf

@@ -0,0 +1,24 @@
+# The graph's clock, floored where the audio sender needs it.
+#
+# Inside a virtual machine, pipewire.conf raises the graph's minimum quantum to
+# 1024 frames (21.3 ms), because a VM's timers jitter and small quanta then
+# underrun on real audio hardware. A box is a VM, so that rule applies, and it
+# silently overrides neswire's request for its 5 ms packet size. Every sample
+# then waits for a 21 ms cycle before it can be encoded.
+#
+# The floor comes down to 256 frames (5.3 ms), the smallest power of two that
+# holds one of neswire's packets. It is not lower than that on purpose: nothing
+# here needs less, and the reason for the rule, a VM's timer driving the graph,
+# still holds, because the Dummy-Driver is exactly that.
+#
+# A drop-in appends to a rules array, and every matching rule applies in order,
+# so this one runs after the shipped one and wins.
+context.properties.rules = [
+    {   matches = [ { cpu.vm.name = !null } ]
+        actions = {
+            update-props = {
+                default.clock.min-quantum = 256
+            }
+        }
+    }
+]

build/etc/wireplumber/wireplumber.conf.d/50-nestri.conf

@@ -3,14 +3,13 @@
 # The goal is that `neswire` is the *only* Audio/Sink in the graph, so
 # default-node selection has exactly one candidate and cannot pick wrong.
 #
-# The "Dummy Output" (`auto_null`) sink is not disabled here, and no longer
-# needs to be: it came from pipewire-pulse's `module-always-sink`, and
-# pipewire-pulse is no longer installed. WirePlumber ships
-# scripts/fallback-sink.lua, which creates a node by the same name, but no
-# component in wireplumber.conf references it, so it never loads. If auto_null
-# ever comes back, it came back with pipewire-pulse -- the switch is
-# `pulse.cmd.always-sink = false` in a pipewire-pulse.conf.d drop-in, not
-# anything on this side.
+# The "Dummy Output" (`auto_null`) sink is not disabled here, because it does
+# not come from this side. pipewire-pulse creates it with `module-always-sink`,
+# and the pipewire-pulse drop-in turns that off with
+# `pulse.cmd.always-sink = false`. WirePlumber ships scripts/fallback-sink.lua,
+# which creates a node by the same name, but no component in wireplumber.conf
+# references it, so it never loads. If auto_null appears, look at the
+# pipewire-pulse drop-in first.
 #
 # pipewire.conf's Dummy-Driver / Freewheel-Driver are a third thing again:
 # support.node.driver objects with no ports -- drivers, not sinks, so nothing