utils: use caps when getting a compatible pad by template

Do not ignore the caps argument when requesting a pad by template.

This is particularly harmful when the pad caps query by default
returns ANY so it will match the first template instead of the
one that actually intersects with the caps.

https://bugzilla.gnome.org/show_bug.cgi?id=751235

diff --git a/gst/gstutils.c b/gst/gstutils.c
index e00f8e8..076de1c 100644 (file)
--- a/gst/gstutils.c
+++ b/gst/gstutils.c
@@ -1099,8 +1099,13 @@ gst_element_get_compatible_pad (GstElement * element, GstPad * pad,
 
   /* try to create a new one */
   /* requesting is a little crazy, we need a template. Let's create one */
-  /* FIXME: why not gst_pad_get_pad_template (pad); */
   templcaps = gst_pad_query_caps (pad, NULL);
+  if (caps) {
+    GstCaps *inter = gst_caps_intersect (templcaps, caps);
+
+    gst_caps_unref (templcaps);
+    templcaps = inter;
+  }
   templ = gst_pad_template_new ((gchar *) GST_PAD_NAME (pad),
       GST_PAD_DIRECTION (pad), GST_PAD_ALWAYS, templcaps);
   gst_caps_unref (templcaps);