diff --git a/libswscale/ops.h b/libswscale/ops.h
index 4d908edba2..86bf3312e6 100644
--- a/libswscale/ops.h
+++ b/libswscale/ops.h
@@ -216,7 +216,7 @@ typedef struct SwsLinearOp {
 enum {
     SWS_MASK_ALL   = (1 << 20) - 1,
     SWS_MASK_LUMA  = SWS_MASK(0, 0) | SWS_MASK_OFF(0),
-    SWS_MASK_ALPHA = SWS_MASK(3, 3) | SWS_MASK_OFF(3),
+    SWS_MASK_ALPHA = SWS_MASK(3, 3),
 
     SWS_MASK_DIAG3 = SWS_MASK(0, 0)  | SWS_MASK(1, 1)  | SWS_MASK(2, 2),
     SWS_MASK_OFF3  = SWS_MASK_OFF(0) | SWS_MASK_OFF(1) | SWS_MASK_OFF(2),
diff --git a/libswscale/x86/ops_float.asm b/libswscale/x86/ops_float.asm
index 4f09ab846e..2d36f6686e 100644
--- a/libswscale/x86/ops_float.asm
+++ b/libswscale/x86/ops_float.asm
@@ -292,7 +292,7 @@ op dither%1
 %xdefine MASK_COL(J) (0x8421 << J)
 %xdefine MASK_ALL    (1 << 20) - 1
 %xdefine MASK_LUMA   MASK(0, 0) | MASK_OFF(0)
-%xdefine MASK_ALPHA  MASK(3, 3) | MASK_OFF(3)
+%xdefine MASK_ALPHA  MASK(3, 3)
 %xdefine MASK_DIAG3  MASK(0, 0) | MASK(1, 1) | MASK(2, 2)
 %xdefine MASK_OFF3   MASK_OFF(0) | MASK_OFF(1) | MASK_OFF(2)
 %xdefine MASK_MAT3   MASK(0, 0) | MASK(0, 1) | MASK(0, 2) |\