diff --git a/libavformat/rtpdec.h b/libavformat/rtpdec.h
index 41c18c1efd..390071e91e 100644
--- a/libavformat/rtpdec.h
+++ b/libavformat/rtpdec.h
@@ -116,6 +116,9 @@ struct RTPDynamicProtocolHandler_s {
     const char enc_name[50];    /* XXX: still why 50 ? ;-) */
     enum AVMediaType codec_type;
     enum CodecID codec_id;
+    int static_payload_id; /* 0 means no payload id is set. 0 is a valid
+                            * payload ID (PCMU), too, but that format doesn't
+                            * require any custom depacketization code. */
 
     // may be null
     int (*parse_sdp_a_line) (AVFormatContext *s,