diff --git a/libavformat/matroskadec.c b/libavformat/matroskadec.c
index 1ea9b807e6c1c2b2b0bb0166984fcaca960235ba..439ee462a535b61d2e33f0c667aad94c08dcbefc 100644
--- a/libavformat/matroskadec.c
+++ b/libavformat/matroskadec.c
@@ -97,8 +97,8 @@ typedef enum {
 typedef const struct EbmlSyntax {
     uint32_t id;
     EbmlType type;
-    int list_elem_size;
-    int data_offset;
+    size_t list_elem_size;
+    size_t data_offset;
     union {
         int64_t     i;
         uint64_t    u;