diff --git a/libavformat/internal.h b/libavformat/internal.h
index cc8c8f4b43..6f1f1c072a 100644
--- a/libavformat/internal.h
+++ b/libavformat/internal.h
@@ -907,7 +907,7 @@ void ff_format_io_close(AVFormatContext *s, AVIOContext **pb);
  * @param s AVFormatContext
  * @param filename URL or file name to open for writing
  */
-int ff_is_http_proto(char *filename);
+int ff_is_http_proto(const char *filename);
 
 /**
  * Parse creation_time in AVFormatContext metadata if exists and warn if the
diff --git a/libavformat/utils.c b/libavformat/utils.c
index 2157f93e7b..509c0ecdce 100644
--- a/libavformat/utils.c
+++ b/libavformat/utils.c
@@ -1802,7 +1802,7 @@ void ff_format_io_close(AVFormatContext *s, AVIOContext **pb)
     *pb = NULL;
 }
 
-int ff_is_http_proto(char *filename) {
+int ff_is_http_proto(const char *filename) {
     const char *proto = avio_find_protocol_name(filename);
     return proto ? (!av_strcasecmp(proto, "http") || !av_strcasecmp(proto, "https")) : 0;
 }