[Desktop/Multimedia] fix pipewire-noise-filter (and make it visible in outputs selection)

desktop/pipewire/pipewire-noise-filter.conf.nix

@@ -0,0 +1,58 @@
+{ lib
+, writeText
+, rnnoise-plugin
+, noiseFilterStrength
+}:
+
+writeText "pipewire-noise-filter.cfg"  ''
+# Noise canceling source
+#
+# start with pipewire -c filter-chain/source-rnnoise.conf
+#
+context.properties = {
+    log.level        = 1
+}
+
+context.spa-libs = {
+    audio.convert.* = audioconvert/libspa-audioconvert
+    support.*       = support/libspa-support
+}
+
+context.modules = [
+    {   name = libpipewire-module-rtkit
+        args = {
+            nice.level   = -11
+        }
+        flags = [ ifexists nofail ]
+    }
+    {   name = libpipewire-module-protocol-native }
+    {   name = libpipewire-module-client-node }
+    {   name = libpipewire-module-adapter }
+
+    {   name = libpipewire-module-filter-chain
+        args = {
+            node.name =  "rnnoise_source"
+            node.description =  "Noise Canceling source"
+            media.name =  "Noise Canceling source"
+            filter.graph = {
+                nodes = [
+                    {
+                        type = ladspa
+                        name = rnnoise
+                        plugin = ${rnnoise-plugin}/lib/ladspa/librnnoise_ladspa.so
+                        label = noise_suppressor_stereo
+                        control = {
+                            "VAD Threshold (%)" ${toString noiseFilterStrength}
+                        }
+                    }
+                ]
+            }
+            capture.props = {
+                node.passive = true
+            }
+            playback.props = {
+                media.class = Audio/Source
+            }
+        }
+    }
+]''