pad: add ACCEPT_INTERCEPT flag

Make a new flag on the pad that tweaks the default behaviour of the
accept-caps function. By default it will check for a subset of the
query-caps result but this is not always desirable. The query-caps
result contains all the constraints to make a good caps decision
upstream but sometimes, like for parsers, not all the constrained caps
fields are known upstream and then a subset check would fail. Switching
to an intersection makes this work again.

See https://bugzilla.gnome.org/show_bug.cgi?id=705024
    https://bugzilla.gnome.org/show_bug.cgi?id=677401

diff --git a/gst/gstpad.c b/gst/gstpad.c
index 8a1cb48..d3c0444 100644 (file)
--- a/gst/gstpad.c
+++ b/gst/gstpad.c
@@ -2830,8 +2830,16 @@ gst_pad_query_accept_caps_default (GstPad * pad, GstQuery * query)
   allowed = gst_pad_query_caps (pad, caps);
 
   if (allowed) {
-    GST_DEBUG_OBJECT (pad, "allowed caps %" GST_PTR_FORMAT, allowed);
-    result = gst_caps_is_subset (caps, allowed);
+    if (GST_PAD_IS_ACCEPT_INTERSECT (pad)) {
+      GST_DEBUG_OBJECT (pad,
+          "allowed caps intersect %" GST_PTR_FORMAT ", caps %" GST_PTR_FORMAT,
+          allowed, caps);
+      result = gst_caps_can_intersect (caps, allowed);
+    } else {
+      GST_DEBUG_OBJECT (pad, "allowed caps subset %" GST_PTR_FORMAT ", caps %"
+          GST_PTR_FORMAT, allowed, caps);
+      result = gst_caps_is_subset (caps, allowed);
+    }
     gst_caps_unref (allowed);
   } else {
     GST_DEBUG_OBJECT (pad, "no compatible caps allowed on the pad");

diff --git a/gst/gstpad.h b/gst/gstpad.h
index a784835..367d4a5 100644 (file)
--- a/gst/gstpad.h
+++ b/gst/gstpad.h
@@ -622,6 +622,10 @@ typedef gboolean  (*GstPadStickyEventsForeachFunction) (GstPad *pad, GstEvent **
  * @GST_PAD_FLAG_PROXY_SCHEDULING: the default query handler will forward
  *                      scheduling queries to the internally linked pads
  *                      instead of discarding them.
+ * @GST_PAD_FLAG_ACCEPT_INTERSECT: the default accept-caps handler will check
+ *                      it the caps intersect the query-caps result instead
+ *                      of checking for a subset. This is interesting for
+ *                      parsers that can accept incompletely specified caps.
  * @GST_PAD_FLAG_LAST: offset to define more flags
  *
  * Pad state flags
@@ -638,6 +642,7 @@ typedef enum {
   GST_PAD_FLAG_PROXY_CAPS       = (GST_OBJECT_FLAG_LAST << 8),
   GST_PAD_FLAG_PROXY_ALLOCATION = (GST_OBJECT_FLAG_LAST << 9),
   GST_PAD_FLAG_PROXY_SCHEDULING = (GST_OBJECT_FLAG_LAST << 10),
+  GST_PAD_FLAG_ACCEPT_INTERSECT = (GST_OBJECT_FLAG_LAST << 11),
   /* padding */
   GST_PAD_FLAG_LAST        = (GST_OBJECT_FLAG_LAST << 16)
 } GstPadFlags;
@@ -791,6 +796,10 @@ struct _GstPadClass {
 #define GST_PAD_SET_PROXY_SCHEDULING(pad)   (GST_OBJECT_FLAG_SET (pad, GST_PAD_FLAG_PROXY_SCHEDULING))
 #define GST_PAD_UNSET_PROXY_SCHEDULING(pad) (GST_OBJECT_FLAG_UNSET (pad, GST_PAD_FLAG_PROXY_SCHEDULING))
 
+#define GST_PAD_IS_ACCEPT_INTERSECT(pad)    (GST_OBJECT_FLAG_IS_SET (pad, GST_PAD_FLAG_ACCEPT_INTERSECT))
+#define GST_PAD_SET_ACCEPT_INTERSECT(pad)   (GST_OBJECT_FLAG_SET (pad, GST_PAD_FLAG_ACCEPT_INTERSECT))
+#define GST_PAD_UNSET_ACCEPT_INTERSECT(pad) (GST_OBJECT_FLAG_UNSET (pad, GST_PAD_FLAG_ACCEPT_INTERSECT))
+
 /**
  * GST_PAD_GET_STREAM_LOCK:
  * @pad: a #GstPad