diff --git a/libavcodec/truemotion2.c b/libavcodec/truemotion2.c
index f077f0e4bd..97c38f7f08 100644
--- a/libavcodec/truemotion2.c
+++ b/libavcodec/truemotion2.c
@@ -441,8 +441,8 @@ static inline int GET_TOK(TM2Context *ctx,int type)
 
 /* recalculate last and delta values for next blocks */
 #define TM2_RECALC_BLOCK(CHR, stride, last, CD) {\
-    CD[0] = CHR[1] - last[1];\
-    CD[1] = (int)CHR[stride + 1] - (int)CHR[1];\
+    CD[0] = (unsigned)CHR[         1] - (unsigned)last[1];\
+    CD[1] = (unsigned)CHR[stride + 1] - (unsigned) CHR[1];\
     last[0] = (int)CHR[stride + 0];\
     last[1] = (int)CHR[stride + 1];}