playsink: Fix reconfiguration after removing text_sink

If we previously had subtitles coming in, the video
may be chained through a text overlay block. Before,
the code would end up trying to link pads that were
already linked and video would not get reconnected
properly.

To fix that, make sure that the candidate
pads are actually unlinked first. If a textoverlay
is present and no longer needed, it will be cleaned
up later in the reconfiguration sequence.

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/1900>

diff --git a/subprojects/gst-plugins-base/gst/playback/gstplaysink.c b/subprojects/gst-plugins-base/gst/playback/gstplaysink.c
index ebef70d..071ba67 100644 (file)
--- a/subprojects/gst-plugins-base/gst/playback/gstplaysink.c
+++ b/subprojects/gst-plugins-base/gst/playback/gstplaysink.c
@@ -3424,19 +3424,43 @@ gst_play_sink_do_reconfigure (GstPlaySink * playsink)
     /* if we are not part of vis or subtitles, set the ghostpad target */
     if (!need_vis && !need_text && (!playsink->textchain
             || !playsink->text_pad)) {
+      GstPad *old_sink_peer = gst_pad_get_peer (playsink->videochain->sinkpad);
+      GstPad *new_peer = NULL;
+
       GST_DEBUG_OBJECT (playsink, "ghosting video sinkpad");
-      gst_pad_unlink (playsink->video_srcpad_stream_synchronizer,
-          playsink->videochain->sinkpad);
-      if (playsink->videodeinterlacechain
-          && playsink->videodeinterlacechain->srcpad)
-        gst_pad_unlink (playsink->videodeinterlacechain->srcpad,
-            playsink->videochain->sinkpad);
       if (need_deinterlace)
-        gst_pad_link_full (playsink->videodeinterlacechain->srcpad,
-            playsink->videochain->sinkpad, GST_PAD_LINK_CHECK_NOTHING);
+        new_peer = playsink->videodeinterlacechain->srcpad;
       else
-        gst_pad_link_full (playsink->video_srcpad_stream_synchronizer,
-            playsink->videochain->sinkpad, GST_PAD_LINK_CHECK_NOTHING);
+        new_peer = playsink->video_srcpad_stream_synchronizer;
+
+      if (old_sink_peer != new_peer) {
+        /* Make sure the srcpad we're linking to is unlinked. This may
+         * leave a deinterlace or text overlay unlinked and lying around,
+         * but that will be cleaned up below */
+        GstPad *old_src_peer = gst_pad_get_peer (new_peer);
+        if (old_src_peer != NULL) {
+          gst_pad_unlink (new_peer, old_src_peer);
+          gst_clear_object (&old_src_peer);
+        }
+
+        /* And that the pad we're linking to is unlinked */
+        if (old_sink_peer != NULL)
+          gst_pad_unlink (old_sink_peer, playsink->videochain->sinkpad);
+
+        if (!GST_PAD_LINK_SUCCESSFUL (gst_pad_link_full (new_peer,
+                    playsink->videochain->sinkpad,
+                    GST_PAD_LINK_CHECK_NOTHING))) {
+          if (need_deinterlace) {
+            GST_WARNING_OBJECT (playsink,
+                "Failed to link deinterlace srcpad to video sinkpad");
+          } else {
+            GST_WARNING_OBJECT (playsink,
+                "Failed to link stream synchronizer srcpad to video sinkpad");
+          }
+        }
+      }
+
+      gst_clear_object (&old_sink_peer);
     }
   } else {
     GST_DEBUG_OBJECT (playsink, "no video needed");