add rnnoise filter

modules/audio/default.nix

@@ -1,10 +1,10 @@
-{ ... }:
+{ pkgs, ... }:
-
 {
   security.rtkit.enable = true;
 
   services.pipewire = {
     enable = true;
+    systemWide = true;
     alsa = {
       enable = true;
       support32Bit = true;
@@ -16,5 +16,42 @@
   };
 
   hardware.pulseaudio.enable = false;
+
+  environment.etc = let
+    json = pkgs.formats.json {};
+  in {
+    "pipewire/pipewire.conf.d/91-rnnoise.conf".source = json.generate "91-rnnoise.conf" {
+      context.modules = [{
+        name = "libpipewire-module-filter-chain";
+        args = {
+          node.description =  "Noise Canceling source";
+          media.name =  "Noise Canceling source";
+          filter.graph = {
+            nodes = [{
+              type = "ladspa";
+              name = "rnnoise";
+              plugin = "${pkgs.rnnoise-plugin}/lib/ladspa/librnnoise_ladspa.so";
+              label = "noise_suppressor_mono";
+              control = {
+                "VAD Threshold (%)" = 50.0;
+                "VAD Grace Period (ms)" = 200;
+                "Retroactive VAD Grace (ms)" = 0;
+              };
+            }];
+          };
+          capture.props = {
+            node.name =  "capture.rnnoise_source";
+            node.passive = true;
+            audio.rate = 48000;
+          };
+          playback.props = {
+            node.name =  "rnnoise_source";
+            media.class = "Audio/Source";
+            audio.rate = 48000;
+          };
+        };
+      }];
+    };
+  };
 }