diff --git a/ntsc-640-err.py b/ntsc-640-err.py
index 347fe47..5834a5c 100755
--- a/ntsc-640-err.py
+++ b/ntsc-640-err.py
@@ -22,10 +22,10 @@ def yuv2rgb(y, u, v):
     b = max(0.0, y + 2.033 * u)
     return r, g, b
 
-def luv2rgb(y, u, v):
-    r = max(0.0, y + v)
-    g = max(0.0, y - 0.707 * u - 0.707 * v)
-    b = max(0.0, y + u)
+def luv2rgb(l, u, v):
+    r = max(0.0, l + v)
+    g = max(0.0, l - 0.707 * u - 0.707 * v)
+    b = max(0.0, l + u)
     return r, g, b
 
 def ntscInitRGB(angle):