Fix overriden typos

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavcodec/mpeg4videodec.c

@@ -1740,7 +1740,7 @@ static int decode_vol_header(Mpeg4DecContext *ctx, GetBitContext *gb)
         }
     } else {
         /* is setting low delay flag only once the smartest thing to do?
-         * low delay detection won't be overriden. */
+         * low delay detection won't be overridden. */
         if (s->picture_number == 0)
             s->low_delay = 0;
     }

libavcodec/mpegvideo.c

@@ -1089,7 +1089,7 @@ static int init_context_frame(MpegEncContext *s)
     mb_array_size = s->mb_height * s->mb_stride;
     mv_table_size = (s->mb_height + 2) * s->mb_stride + 1;
 
-    /* set default edge pos, will be overriden
+    /* set default edge pos, will be overridden
      * in decode_header if needed */
     s->h_edge_pos = s->mb_width * 16;
     s->v_edge_pos = s->mb_height * 16;