diff --git a/libavformat/avformat.h b/libavformat/avformat.h
index 7fc10a33f518b44f77a563f1a0f6140ce5b00a20..69d0054ada8a96406ebf95a8a935940d6279fd15 100644
--- a/libavformat/avformat.h
+++ b/libavformat/avformat.h
@@ -738,8 +738,8 @@ attribute_deprecated AVOutputFormat *guess_format(const char *short_name,
  * MIME type of the registered formats
  */
 AVOutputFormat *av_guess_format(const char *short_name,
-                             const char *filename,
-                             const char *mime_type);
+                                const char *filename,
+                                const char *mime_type);
 
 /**
  * Guesses the codec ID based upon muxer and filename.