diff --git a/docs/fs.md b/docs/fs.md
index 974e615..9511137 100644
--- a/docs/fs.md
+++ b/docs/fs.md
@@ -21,9 +21,11 @@
 {
   "title": "EFN",
   "icon": "icon.png",
-  "start": "MENU 1"
+  "start": "MENU 1",
+  "mainVideo": "1"
 }
 ```
 - **title:** title of the FOD project, may be optionally shown on players
 - **icon:** the filename of 256x256 PNG file in the "META" folder that will be used as icon, may be optionally shown on players
-- **start:** the starting point of the FOD, it's characterized by the type of start point ("MENU" or "VIDEO") and its ID
\ No newline at end of file
+- **start:** the starting point of the FOD, it's characterized by the type of start point ("MENU" or "VIDEO") and its ID
+- **mainVideo:** main video file for players that don't support interactive menus
\ No newline at end of file