st2022-1-fecdec: fix packet trimming

g_sequence_remove_range's end iter is exclusive, so if one
wants to remove that item as well, it should be called with
the next iter.

This could in theory fix an issue where:

* The sequence isn't entirely trimmed, with an old item lingering

* Following FEC packets are immediately discarded because they
  arrived later than corresponding media packets, long enough for
  seqnums to wrap around

* We now try to reconstruct a media packet with a completely obsolete
  FEC packet, chaos ensues.

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/1341>

diff --git a/subprojects/gst-plugins-good/gst/rtpmanager/gstrtpst2022-1-fecdec.c b/subprojects/gst-plugins-good/gst/rtpmanager/gstrtpst2022-1-fecdec.c
index ca9884f..77b275f 100644 (file)
--- a/subprojects/gst-plugins-good/gst/rtpmanager/gstrtpst2022-1-fecdec.c
+++ b/subprojects/gst-plugins-good/gst/rtpmanager/gstrtpst2022-1-fecdec.c
@@ -221,7 +221,8 @@ trim_items (GstRTPST_2022_1_FecDec * dec)
     GST_TRACE_OBJECT (dec,
         "Trimming packets up to %" GST_TIME_FORMAT " (seq: %u)",
         GST_TIME_ARGS (GST_BUFFER_DTS_OR_PTS (item->buffer)), item->seq);
-    g_sequence_remove_range (g_sequence_get_begin_iter (dec->packets), iter);
+    g_sequence_remove_range (g_sequence_get_begin_iter (dec->packets),
+        g_sequence_iter_next (iter));
   }
 }
 
@@ -263,7 +264,7 @@ trim_fec_items (GstRTPST_2022_1_FecDec * dec, guint D)
         D ? "row" : "column",
         GST_TIME_ARGS (GST_BUFFER_DTS_OR_PTS (item->buffer)), item->seq);
     g_sequence_remove_range (g_sequence_get_begin_iter (dec->fec_packets[D]),
-        iter);
+        g_sequence_iter_next (iter));
   }
 }