decodebin: return incomplete topology if decode chains' cap could not be obtained

When getting caps of the decode chain, in get_topology, the caps are being
checked if fixed or not. But get_topology will be called when the decode is
chain is being exposed and hence it will always be fixed. Hence removing the
check for fixed caps. Removing gst_pad_get_current_caps for the chain->pad, as
get_pad_caps will again call the same api.

And get_topology can return NULL value if currently shutting down the
pipeline, which on being passed to create message will result in assertion
error. Check if topology is valid before using it

https://bugzilla.gnome.org/show_bug.cgi?id=755918

diff --git a/gst/playback/gstdecodebin2.c b/gst/playback/gstdecodebin2.c
index 73d835da5bbc0ab5eeb28a4e65730176268c8f9f..1dfe6a31f76b011f0b0d2d04236de950257e16ff 100644 (file)
--- a/gst/playback/gstdecodebin2.c
+++ b/gst/playback/gstdecodebin2.c
@@ -4497,15 +4497,10 @@ gst_decode_chain_get_topology (GstDecodeChain * chain)
   }
 
   /* Caps that resulted in this chain */
-  caps = gst_pad_get_current_caps (chain->pad);
-  if (!caps) {
-    caps = get_pad_caps (chain->pad);
-    if (G_UNLIKELY (!gst_caps_is_fixed (caps))) {
-      GST_ERROR_OBJECT (chain->pad,
-          "Couldn't get fixed caps, got %" GST_PTR_FORMAT, caps);
-      gst_caps_unref (caps);
-      caps = NULL;
-    }
+  caps = get_pad_caps (chain->pad);
+  if (G_UNLIKELY (!caps)) {
+    GST_WARNING_OBJECT (chain->pad, "Couldn't get the caps of decode chain");
+    return u;
   }
   gst_structure_id_set (u, topology_caps, GST_TYPE_CAPS, caps, NULL);
   gst_structure_id_set (u, topology_element_srcpad, GST_TYPE_PAD, chain->pad,
@@ -4523,6 +4518,8 @@ gst_decode_bin_post_topology_message (GstDecodeBin * dbin)
 
   s = gst_decode_chain_get_topology (dbin->decode_chain);
 
+  if (G_UNLIKELY (s == NULL))
+    return;
   msg = gst_message_new_element (GST_OBJECT (dbin), s);
   gst_element_post_message (GST_ELEMENT (dbin), msg);
 }