From ed5db9bce79660358749edb3b08cd820ad437fe4 Mon Sep 17 00:00:00 2001
From: Edward Hervey <edward@centricular.com>
Date: Thu, 14 Apr 2022 15:21:48 +0200
Subject: [PATCH] decodebin3: Don't duplicate stream selections

Make sure that the requested stream selection isn't identical to the current
one. If that's the case, just carry on as usual.

This avoids multiple `streams-selected` posting ... when the selection didn't
change.

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/2185>
---
 .../gst/playback/gstdecodebin3.c              | 26 ++++++++++++++++++-
 1 file changed, 25 insertions(+), 1 deletion(-)

diff --git a/subprojects/gst-plugins-base/gst/playback/gstdecodebin3.c b/subprojects/gst-plugins-base/gst/playback/gstdecodebin3.c
index 6209d653b5..514cd1a77d 100644
--- a/subprojects/gst-plugins-base/gst/playback/gstdecodebin3.c
+++ b/subprojects/gst-plugins-base/gst/playback/gstdecodebin3.c
@@ -1177,6 +1177,23 @@ stream_in_list (GList * list, const gchar * sid)
   return NULL;
 }
 
+static gboolean
+stream_list_equal (GList * lista, GList * listb)
+{
+  GList *tmp;
+
+  if (g_list_length (lista) != g_list_length (listb))
+    return FALSE;
+
+  for (tmp = lista; tmp; tmp = tmp->next) {
+    gchar *osid = tmp->data;
+    if (!stream_in_list (listb, osid))
+      return FALSE;
+  }
+
+  return TRUE;
+}
+
 static void
 update_requested_selection (GstDecodebin3 * dbin)
 {
@@ -1253,8 +1270,15 @@ update_requested_selection (GstDecodebin3 * dbin)
   }
 
 beach:
-  /* Finally set the requested selection */
+  if (stream_list_equal (tmp, dbin->requested_selection)) {
+    /* If the selection is equal, there is nothign to do */
+    GST_DEBUG_OBJECT (dbin, "Dropping duplicate selection");
+    g_list_free (tmp);
+    tmp = NULL;
+  }
+
   if (tmp) {
+    /* Finally set the requested selection */
     if (dbin->requested_selection) {
       GST_FIXME_OBJECT (dbin,
           "Replacing non-NULL requested_selection, what should we do ??");