diff --git a/libavformat/isom.c b/libavformat/isom.c
index 73ee3285f0..39c58c64df 100644
--- a/libavformat/isom.c
+++ b/libavformat/isom.c
@@ -274,7 +274,7 @@ int ff_mov_iso639_to_lang(const char *lang, int mp4)
     return code;
 }
 
-int ff_mov_lang_to_iso639(int code, char *to)
+int ff_mov_lang_to_iso639(unsigned code, char *to)
 {
     int i;
     /* is it the mangled iso code? */
diff --git a/libavformat/isom.h b/libavformat/isom.h
index 934dde8388..2cad5b8b68 100644
--- a/libavformat/isom.h
+++ b/libavformat/isom.h
@@ -33,7 +33,7 @@ extern const AVCodecTag codec_movaudio_tags[];
 extern const AVCodecTag ff_codec_movsubtitle_tags[];
 
 int ff_mov_iso639_to_lang(const char *lang, int mp4);
-int ff_mov_lang_to_iso639(int code, char *to);
+int ff_mov_lang_to_iso639(unsigned code, char *to);
 
 typedef struct {
     int count;
diff --git a/libavformat/mov.c b/libavformat/mov.c
index fc946ea33a..0a93444d18 100644
--- a/libavformat/mov.c
+++ b/libavformat/mov.c
@@ -494,7 +494,7 @@ static int mov_read_mdhd(MOVContext *c, ByteIOContext *pb, MOVAtom atom)
     AVStream *st = c->fc->streams[c->fc->nb_streams-1];
     MOVStreamContext *sc = st->priv_data;
     int version = get_byte(pb);
-    int lang;
+    unsigned lang;
 
     if (version > 1)
         return -1; /* unsupported */