diff --git a/libavcodec/diracdec.c b/libavcodec/diracdec.c
index 033fbe4261..da5240a135 100644
--- a/libavcodec/diracdec.c
+++ b/libavcodec/diracdec.c
@@ -1353,8 +1353,8 @@ static void decode_block_params(DiracContext *s, DiracArith arith[8], DiracBlock
                 global_mv(s, block, x, y, i);
             } else {
                 pred_mv(block, stride, x, y, i);
-                block->u.mv[i][0] += dirac_get_arith_int(arith + 4 + 2 * i, CTX_MV_F1, CTX_MV_DATA);
-                block->u.mv[i][1] += dirac_get_arith_int(arith + 5 + 2 * i, CTX_MV_F1, CTX_MV_DATA);
+                block->u.mv[i][0] += (unsigned)dirac_get_arith_int(arith + 4 + 2 * i, CTX_MV_F1, CTX_MV_DATA);
+                block->u.mv[i][1] += (unsigned)dirac_get_arith_int(arith + 5 + 2 * i, CTX_MV_F1, CTX_MV_DATA);
             }
         }
 }