diff --git a/libavformat/rtpdec.h b/libavformat/rtpdec.h
index 366102af99..1e56e9e40a 100644
--- a/libavformat/rtpdec.h
+++ b/libavformat/rtpdec.h
@@ -140,7 +140,7 @@ struct RTPDynamicProtocolHandler_s {
                              int st_index,
                              PayloadContext *priv_data,
                              const char *line); ///< Parse the a= line from the sdp field
-    PayloadContext *(*open) (); ///< allocate any data needed by the rtp parsing for this dynamic data.
+    PayloadContext *(*open) (void); ///< allocate any data needed by the rtp parsing for this dynamic data.
     void (*close)(PayloadContext *protocol_data); ///< free any data needed by the rtp parsing for this dynamic data.
     DynamicPayloadPacketHandlerProc parse_packet; ///< parse handler for this dynamic packet.