go2tv: partially fix the -tc option

overlays/preferences.nix

@@ -81,7 +81,31 @@ in
     # done as overlay instead of in hosts/common/programs/go2tv.nix so that python consumers like sane-cast also get this fix.
     postPatch = (upstream.postPatch or "") + ''
       substituteInPlace devices/devices.go --replace-fail "port := 1900" "port := 1901"
+
+      # by default, go2tv passes `ffmpeg -re`, which limits ffmpeg to never stream faster than realtime.
+      # patch that out to let the receiver stream as fast as it wants.
+      # maybe not necessary, was added during debugging.
+      substituteInPlace soapcalls/utils/transcode.go --replace-fail '"-re",' ""
     '';
+
+    patches = (upstream.patches or []) ++ [
+      (fetchpatch {
+        name = "enable ffmpeg functionality outside the GUI paths";
+        url = "https://git.uninsane.org/colin/go2tv/commit/9afa10dd2e2ef16def26be07eb72fbc5b0382ddd.patch";
+        hash = "sha256-PW989bb/xHk7EncZ3Ra69y2p1U1XeePKq2h7v5O47go=";
+      })
+      (fetchpatch {
+        # this causes it to advertize that weird `video/vnd.dlna.mpeg-tts` MIME type.
+        # TODO: try `video/mpeg`.
+        # the following were tried, and failed:
+        # - video/mp2t
+        # - video/x-mpegts
+        # - video/MP2T
+        name = "advertise the correct MediaType when transcoding";
+        url = "https://git.uninsane.org/colin/go2tv/commit/3bbb98318df2fc3d1a61cecd2b06d1bec9964651.patch";
+        hash = "sha256-9n43QXfCWyEn5qw1rWnmFb8oTY6xgkih5ySAcxdBVZo=";
+      })
+    ];
   });
 
   # gnome-control-center = super.gnome-control-center.override {