diff --git a/libavformat/avformat.h b/libavformat/avformat.h
index be1ec1c24a..77745ba813 100644
--- a/libavformat/avformat.h
+++ b/libavformat/avformat.h
@@ -1079,6 +1079,16 @@ int av_interleaved_write_frame(AVFormatContext *s, AVPacket *pkt);
 int av_interleave_packet_per_dts(AVFormatContext *s, AVPacket *out,
                                  AVPacket *pkt, int flush);
 
+/**
+ * Add packet to AVFormatContext->packet_buffer list, determining its
+ * interleaved position using compare() function argument.
+ *
+ * This function is not part of the public API and should only be called
+ * by muxers using their own interleave function.
+ */
+void ff_interleave_add_packet(AVFormatContext *s, AVPacket *pkt,
+                              int (*compare)(AVFormatContext *, AVPacket *, AVPacket *));
+
 /**
  * @brief Write the stream trailer to an output media file and
  *        free the file private data.