diff --git a/libavcodec/dxtory.c b/libavcodec/dxtory.c
index 7143a11e2e..f314bcec75 100644
--- a/libavcodec/dxtory.c
+++ b/libavcodec/dxtory.c
@@ -264,8 +264,8 @@ static int dxtory_decode_v1_420(AVCodecContext *avctx, AVFrame *pic,
             V[huvborder] = src[3] + 0x80;
             src += 4;
         }
-        Y1 += pic->linesize[0] << 1;
-        Y2 += pic->linesize[0] << 1;
+        Y1 += pic->linesize[0] * 2;
+        Y2 += pic->linesize[0] * 2;
         U  += pic->linesize[1];
         V  += pic->linesize[2];
     }