diff --git a/libavformat/mpc8.c b/libavformat/mpc8.c
index 4d95a1dbf2..3193f5d570 100644
--- a/libavformat/mpc8.c
+++ b/libavformat/mpc8.c
@@ -54,7 +54,7 @@ typedef struct {
 
 static inline int64_t bs_get_v(uint8_t **bs)
 {
-    int64_t v = 0;
+    uint64_t v = 0;
     int br = 0;
     int c;
 
@@ -105,7 +105,7 @@ static int mpc8_probe(AVProbeData *p)
 
 static inline int64_t gb_get_v(GetBitContext *gb)
 {
-    int64_t v = 0;
+    uint64_t v = 0;
     int bits = 0;
     while(get_bits1(gb) && bits < 64-7){
         v <<= 7;