basetextoverlay: properly fallback to non-overlay caps

When downstream claims to accept the overlay meta but fails to
provide it in the allocation query, properly fallback to setting
a new caps without the overlay meta as that is not going to be used.

Only do this if the original caps doesn't have the overlay already,
otherwise there isn't much that can be done.

https://bugzilla.gnome.org/show_bug.cgi?id=735800

diff --git a/ext/pango/gstbasetextoverlay.c b/ext/pango/gstbasetextoverlay.c
index 7036d98..4dd1984 100644 (file)
--- a/ext/pango/gstbasetextoverlay.c
+++ b/ext/pango/gstbasetextoverlay.c
@@ -310,9 +310,11 @@ static void gst_base_text_overlay_set_property (GObject * object, guint prop_id,
     const GValue * value, GParamSpec * pspec);
 static void gst_base_text_overlay_get_property (GObject * object, guint prop_id,
     GValue * value, GParamSpec * pspec);
+
 static void
 gst_base_text_overlay_adjust_values_with_fontdesc (GstBaseTextOverlay * overlay,
     PangoFontDescription * desc);
+static gboolean gst_base_text_overlay_can_handle_caps (GstCaps * incaps);
 
 GType
 gst_base_text_overlay_get_type (void)
@@ -717,6 +719,8 @@ gst_base_text_overlay_negotiate (GstBaseTextOverlay * overlay, GstCaps * caps)
   gboolean caps_has_meta = TRUE;
   gboolean ret;
   GstCapsFeatures *f;
+  GstCaps *original_caps;
+  gboolean original_has_meta = FALSE;
 
   GST_DEBUG_OBJECT (overlay, "performing negotiation");
 
@@ -728,6 +732,8 @@ gst_base_text_overlay_negotiate (GstBaseTextOverlay * overlay, GstCaps * caps)
   if (!caps || gst_caps_is_empty (caps))
     goto no_format;
 
+  original_caps = caps;
+
   /* Try to use the overlay meta if possible */
   f = gst_caps_get_features (caps, 0);
 
@@ -758,7 +764,8 @@ gst_base_text_overlay_negotiate (GstBaseTextOverlay * overlay, GstCaps * caps)
       gst_caps_unref (overlay_caps);
       caps_has_meta = FALSE;
     }
-
+  } else {
+    original_has_meta = TRUE;
   }
   GST_DEBUG_OBJECT (overlay, "Using caps %" GST_PTR_FORMAT, caps);
   ret = gst_pad_set_caps (overlay->srcpad, caps);
@@ -781,6 +788,20 @@ gst_base_text_overlay_negotiate (GstBaseTextOverlay * overlay, GstCaps * caps)
   } else {
     overlay->attach_compo_to_buffer = FALSE;
   }
+
+  if (original_caps && !original_has_meta && !attach) {
+    if (caps_has_meta) {
+      /* Some elements (fakesink) claim to accept the meta on caps but won't
+         put it in the allocation query result, this leads below
+         check to fail. Prevent this by removing the meta from caps */
+      gst_caps_unref (caps);
+      caps = gst_caps_ref (original_caps);
+      ret = gst_pad_set_caps (overlay->srcpad, caps);
+      if (ret && !gst_base_text_overlay_can_handle_caps (caps))
+        ret = FALSE;
+    }
+  }
+
   gst_caps_unref (caps);
 
   return ret;