diff --git a/libavcodec/mmvideo.c b/libavcodec/mmvideo.c
index 6dbc0c4494..0b20ab4d1d 100644
--- a/libavcodec/mmvideo.c
+++ b/libavcodec/mmvideo.c
@@ -78,6 +78,10 @@ static void mm_decode_pal(MmContext *s, const uint8_t *buf, const uint8_t *buf_e
     }
 }
 
+/**
+ * @param half_horiz Half horizontal resolution (0 or 1)
+ * @param half_vert Half vertical resolution (0 or 1)
+ */
 static void mm_decode_intra(MmContext * s, int half_horiz, int half_vert, const uint8_t *buf, int buf_size)
 {
     int i, x, y;
@@ -108,11 +112,15 @@ static void mm_decode_intra(MmContext * s, int half_horiz, int half_vert, const
 
         if (x >= s->avctx->width) {
             x=0;
-            y += half_vert ? 2 : 1;
+            y += 1 + half_vert;
         }
     }
 }
 
+/*
+ * @param half_horiz Half horizontal resolution (0 or 1)
+ * @param half_vert Half vertical resolution (0 or 1)
+ */
 static void mm_decode_inter(MmContext * s, int half_horiz, int half_vert, const uint8_t *buf, int buf_size)
 {
     const int data_ptr = 2 + AV_RL16(&buf[0]);
@@ -145,12 +153,12 @@ static void mm_decode_inter(MmContext * s, int half_horiz, int half_vert, const
                     }
                     d++;
                 }
-                x += half_horiz ? 2 : 1;
+                x += 1 + half_horiz;
             }
         }
 
         r += length;
-        y += half_vert ? 2 : 1;
+        y += 1 + half_vert;
     }
 }