diff --git a/nixos/modules/services/audio/mopidy.nix b/nixos/modules/services/audio/mopidy.nix
index 1ec1950a0970..05ab6e8bce87 100644
--- a/nixos/modules/services/audio/mopidy.nix
+++ b/nixos/modules/services/audio/mopidy.nix
@@ -55,6 +55,7 @@ in
 
       settings = lib.mkOption {
         inherit (settingsFormat) type;
+        default = { };
         example.mpd = {
           enabled = true;
           hostname = "::";
diff --git a/pkgs/applications/audio/mopidy/mopidy.nix b/pkgs/applications/audio/mopidy/mopidy.nix
index b97bc975612b..2465b0256aa9 100644
--- a/pkgs/applications/audio/mopidy/mopidy.nix
+++ b/pkgs/applications/audio/mopidy/mopidy.nix
@@ -34,6 +34,7 @@ pythonPackages.buildPythonApplication (finalAttrs: {
       gst-plugins-good
       gst-plugins-ugly
       gst-plugins-rs
+      gst-libav
     ]
     ++ lib.optionals (!stdenv.hostPlatform.isDarwin) [ pipewire ];