Defaults: firefox.disableAv1 on, Jellyfin hardware decoding on when nix-flatpak installs it

modules/firefox.nix

@@ -28,7 +28,9 @@ let
   ffDir = "$HOME/.var/app/org.mozilla.firefox/config/mozilla/firefox";
   profileDir = "${ffDir}/${cfg.desktopProfile}";
 
-  defaultPrefs = cfg.prefs // lib.optionalAttrs cfg.vrFullscreenFix { "full-screen-api.ignore-widgets" = true; };
+  defaultPrefs = lib.optionalAttrs cfg.disableAv1 { "media.av1.enabled" = false; }
+    // lib.optionalAttrs cfg.vrFullscreenFix { "full-screen-api.ignore-widgets" = true; }
+    // cfg.prefs;
   desktopFix = cfg.enable && cfg.vrFullscreenFix && cfg.desktopProfile != null;
   # Only ever this one pref (profileSync relies on it).
   desktopKeys = [ "full-screen-api.ignore-widgets" ];
@@ -130,17 +132,24 @@ in {
         Steam session.
       '';
     };
+    disableAv1 = lib.mkOption {
+      type = lib.types.bool;
+      default = true;
+      description = ''
+        Default media.av1.enabled to false: the Frame's decoder driver has no
+        AV1 (H.264, HEVC, VP9 only), so sites like YouTube send VP9/H.264,
+        decoded in hardware, instead of software-decoded AV1.
+      '';
+    };
     prefs = lib.mkOption {
       type = with lib.types; attrsOf (oneOf [ bool int str ]);
       default = { };
-      example = { "media.av1.enabled" = false; };
+      example = { "media.autoplay.default" = 5; };
       description = ''
-        about:config preferences for every profile (desktop one included),
-        as default values: about:config can still change them for a profile,
-        and removing one here leaves nothing behind. E.g. media.av1.enabled =
-        false: the Frame's decoder has no AV1, so sites like YouTube fall back
-        to VP9/H.264, which it decodes in hardware. Take effect at the next
-        start of Firefox.
+        Further about:config preferences for every profile (desktop one
+        included), as default values: about:config can still change them for
+        a profile, and removing one here leaves nothing behind. Override the
+        fixes above too. Take effect at the next start of Firefox.
       '';
     };
     desktopProfile = lib.mkOption {

modules/jellyfin.nix

@@ -32,12 +32,19 @@ let
     override));
 in {
   options.steamFrame.jellyfin.hardwareDecoding = {
-    enable = lib.mkEnableOption ''
-      hardware video decoding (the Frame's V4L2 decoder) in the Jellyfin
-      Desktop Flatpak: device access for the sandbox (devices=all) and an
-      LD_PRELOAD shim that makes mpv try hwdec's value below. Without
-      nix-flatpak, home-manager owns the app's Flatpak override file. Takes
-      effect at the next start of Jellyfin'';
+    enable = lib.mkOption {
+      type = lib.types.bool;
+      default = lib.any (p: (if builtins.isString p then p else p.appId or null) == app)
+        (config.services.flatpak.packages or [ ]);
+      defaultText = lib.literalMD "`true` if nix-flatpak installs `org.jellyfin.JellyfinDesktop` (`services.flatpak.packages`), else `false`";
+      description = ''
+        Hardware video decoding (the Frame's V4L2 decoder) in the Jellyfin
+        Desktop Flatpak: device access for the sandbox (devices=all) and an
+        LD_PRELOAD shim that makes mpv try hwdec's value below. Without
+        nix-flatpak, home-manager owns the app's Flatpak override file. Takes
+        effect at the next start of Jellyfin.
+      '';
+    };
     hwdec = lib.mkOption {
       type = lib.types.strMatching "[^[:space:]]+";
       default = "v4l2m2m-copy,auto-copy";