diff --git a/libavcodec/ccaption_dec.c b/libavcodec/ccaption_dec.c
index b191b08320..c971c91693 100644
--- a/libavcodec/ccaption_dec.c
+++ b/libavcodec/ccaption_dec.c
@@ -240,7 +240,7 @@ typedef struct CCaptionSubContext {
     int64_t buffer_time[2];
     int screen_touched;
     int64_t last_real_time;
-    char prev_cmd[2];
+    uint8_t prev_cmd[2];
     int readorder;
 } CCaptionSubContext;