diff --git a/video/img_format.c b/video/img_format.c
index 1d0b7c4a72..e1636e1eb6 100644
--- a/video/img_format.c
+++ b/video/img_format.c
@@ -211,13 +211,8 @@ struct mp_imgfmt_desc mp_imgfmt_get_desc(int mpfmt)
         desc.flags |= MP_IMGFLAG_RGB;
     }
 
-#ifdef AV_PIX_FMT_FLAG_ALPHA
     if (pd->flags & AV_PIX_FMT_FLAG_ALPHA)
         desc.flags |= MP_IMGFLAG_ALPHA;
-#else
-    if (desc.num_planes > 3)
-        desc.flags |= MP_IMGFLAG_ALPHA;
-#endif
 
     if (mpfmt >= IMGFMT_RGB0_START && mpfmt <= IMGFMT_RGB0_END)
         desc.flags &= ~MP_IMGFLAG_ALPHA;