pad: don't use buffer caps for negotiation

Don't use the buffer caps for negotiation anymore but use the CAPS events.
Make the _set_caps method produce the CAPS event, add some backward
compatibility code to trigger the setcaps functions on src and sinkpads.
Remove all negotiation code from the chain functions.
Don't use the GST_PAD_CAPS variable anymore to store the caps but retrieve the
caps from the sticky event array.

diff --git a/gst/gstpad.c b/gst/gstpad.c
index 4dcc297..0c83011 100644 (file)
--- a/gst/gstpad.c
+++ b/gst/gstpad.c
@@ -100,7 +100,6 @@ typedef struct _GstPadPushCache GstPadPushCache;
 struct _GstPadPushCache
 {
   GstPad *peer;                 /* reffed peer pad */
-  GstCaps *caps;                /* caps for this link */
 };
 
 static GstPadPushCache _pad_cache_invalid = { NULL, };
@@ -346,14 +345,6 @@ gst_pad_init (GstPad * pad)
   pad->priv = GST_PAD_GET_PRIVATE (pad);
 
   GST_PAD_DIRECTION (pad) = GST_PAD_UNKNOWN;
-  GST_PAD_PEER (pad) = NULL;
-
-  GST_PAD_CHAINFUNC (pad) = NULL;
-
-  GST_PAD_LINKFUNC (pad) = NULL;
-
-  GST_PAD_CAPS (pad) = NULL;
-  GST_PAD_GETCAPSFUNC (pad) = NULL;
 
   GST_PAD_ACTIVATEFUNC (pad) = gst_pad_activate_default;
   GST_PAD_EVENTFUNC (pad) = gst_pad_event_default;
@@ -363,9 +354,6 @@ gst_pad_init (GstPad * pad)
 
   GST_PAD_ACCEPTCAPSFUNC (pad) = gst_pad_acceptcaps_default;
 
-  pad->do_buffer_signals = 0;
-  pad->do_event_signals = 0;
-
   GST_PAD_SET_FLUSHING (pad);
 
   /* FIXME 0.11: Store this directly in the instance struct */
@@ -398,6 +386,19 @@ copy_events (GstEvent * events[], GstEvent * dest[])
   }
 }
 
+static GstCaps *
+get_pad_caps (GstPad * pad)
+{
+  GstCaps *caps = NULL;
+  GstEvent *event;
+  guint idx;
+
+  idx = GST_EVENT_STICKY_IDX_TYPE (GST_EVENT_CAPS);
+  if ((event = pad->priv->events[idx]))
+    gst_event_parse_caps (event, &caps);
+
+  return caps;
+}
 
 static void
 gst_pad_dispose (GObject * object)
@@ -420,9 +421,6 @@ gst_pad_dispose (GObject * object)
     gst_object_unref (peer);
   }
 
-  /* clear the caps */
-  gst_caps_replace (&GST_PAD_CAPS (pad), NULL);
-
   gst_pad_set_pad_template (pad, NULL);
 
   if (pad->block_destroy_data && pad->block_data) {
@@ -490,7 +488,7 @@ gst_pad_get_property (GObject * object, guint prop_id,
   switch (prop_id) {
     case PAD_PROP_CAPS:
       GST_OBJECT_LOCK (object);
-      g_value_set_boxed (value, GST_PAD_CAPS (object));
+      g_value_set_boxed (value, get_pad_caps (GST_PAD_CAST (object)));
       GST_OBJECT_UNLOCK (object);
       break;
     case PAD_PROP_DIRECTION:
@@ -2234,7 +2232,7 @@ gst_pad_get_caps_unlocked (GstPad * pad)
     result = gst_caps_ref (result);
     goto done;
   }
-  if ((result = GST_PAD_CAPS (pad))) {
+  if ((result = get_pad_caps (pad))) {
     GST_CAT_DEBUG_OBJECT (GST_CAT_CAPS, pad,
         "using pad caps %p %" GST_PTR_FORMAT, result, result);
 
@@ -2470,7 +2468,9 @@ gst_pad_accept_caps (GstPad * pad, GstCaps * caps)
 {
   gboolean result;
   GstPadAcceptCapsFunction acceptfunc;
+#if 0
   GstCaps *existing = NULL;
+#endif
 
   g_return_val_if_fail (GST_IS_PAD (pad), FALSE);
 
@@ -2481,11 +2481,13 @@ gst_pad_accept_caps (GstPad * pad, GstCaps * caps)
   /* lock for checking the existing caps */
   GST_OBJECT_LOCK (pad);
   GST_CAT_DEBUG_OBJECT (GST_CAT_CAPS, pad, "accept caps of %p", caps);
+#if 0
   /* The current caps on a pad are trivially acceptable */
   if (G_LIKELY ((existing = GST_PAD_CAPS (pad)))) {
     if (caps == existing || gst_caps_is_equal (caps, existing))
       goto is_same_caps;
   }
+#endif
   acceptfunc = GST_PAD_ACCEPTCAPSFUNC (pad);
   GST_OBJECT_UNLOCK (pad);
 
@@ -2500,12 +2502,14 @@ gst_pad_accept_caps (GstPad * pad, GstCaps * caps)
   }
   return result;
 
+#if 0
 is_same_caps:
   {
     GST_DEBUG_OBJECT (pad, "pad had same caps");
     GST_OBJECT_UNLOCK (pad);
     return TRUE;
   }
+#endif
 }
 
 /**
@@ -2570,76 +2574,19 @@ no_peer:
 gboolean
 gst_pad_set_caps (GstPad * pad, GstCaps * caps)
 {
-  GstPadSetCapsFunction setcaps;
-  GstCaps *existing;
+  GstEvent *event;
 
   g_return_val_if_fail (GST_IS_PAD (pad), FALSE);
   g_return_val_if_fail (caps == NULL || gst_caps_is_fixed (caps), FALSE);
 
-  GST_OBJECT_LOCK (pad);
-  existing = GST_PAD_CAPS (pad);
-  if (existing == caps)
-    goto was_ok;
-
-  if (gst_caps_is_equal (caps, existing))
-    goto setting_same_caps;
+  event = gst_event_new_caps (caps);
 
-  setcaps = GST_PAD_SETCAPSFUNC (pad);
-
-  /* call setcaps function to configure the pad only if the
-   * caps is not NULL */
-  if (setcaps != NULL && caps) {
-    if (!GST_PAD_IS_IN_SETCAPS (pad)) {
-      GST_OBJECT_FLAG_SET (pad, GST_PAD_IN_SETCAPS);
-      GST_OBJECT_UNLOCK (pad);
-      if (!setcaps (pad, caps))
-        goto could_not_set;
-      GST_OBJECT_LOCK (pad);
-      GST_OBJECT_FLAG_UNSET (pad, GST_PAD_IN_SETCAPS);
-    } else {
-      GST_CAT_DEBUG_OBJECT (GST_CAT_CAPS, pad, "pad was dispatching");
-    }
-  }
-
-  gst_caps_replace (&GST_PAD_CAPS (pad), caps);
-  GST_CAT_DEBUG_OBJECT (GST_CAT_CAPS, pad, "caps %p %" GST_PTR_FORMAT, caps,
-      caps);
-  GST_OBJECT_UNLOCK (pad);
-
-#if GLIB_CHECK_VERSION(2,26,0)
-  g_object_notify_by_pspec ((GObject *) pad, pspec_caps);
-#else
-  g_object_notify ((GObject *) pad, "caps");
-#endif
+  if (GST_PAD_IS_SRC (pad))
+    gst_pad_push_event (pad, event);
+  else
+    gst_pad_send_event (pad, event);
 
   return TRUE;
-
-was_ok:
-  {
-    GST_OBJECT_UNLOCK (pad);
-    return TRUE;
-  }
-setting_same_caps:
-  {
-    gst_caps_replace (&GST_PAD_CAPS (pad), caps);
-    GST_CAT_DEBUG_OBJECT (GST_CAT_CAPS, pad,
-        "caps %p %" GST_PTR_FORMAT " same as existing, updating ptr only", caps,
-        caps);
-    GST_OBJECT_UNLOCK (pad);
-    return TRUE;
-  }
-
-  /* ERRORS */
-could_not_set:
-  {
-    GST_OBJECT_LOCK (pad);
-    GST_OBJECT_FLAG_UNSET (pad, GST_PAD_IN_SETCAPS);
-    GST_CAT_DEBUG_OBJECT (GST_CAT_CAPS, pad,
-        "caps %" GST_PTR_FORMAT " could not be set", caps);
-    GST_OBJECT_UNLOCK (pad);
-
-    return FALSE;
-  }
 }
 
 static GstFlowReturn
@@ -2669,45 +2616,49 @@ no_function:
 }
 
 static gboolean
-gst_pad_configure_sink (GstPad * pad, GstCaps * caps)
+gst_pad_call_setcaps (GstPad * pad, GstCaps * caps)
 {
-  gboolean res;
+  GstPadSetCapsFunction setcaps;
 
-  /* See if pad accepts the caps */
-  if (!gst_caps_can_intersect (caps, gst_pad_get_pad_template_caps (pad)))
-    goto not_accepted;
+  GST_OBJECT_LOCK (pad);
+  setcaps = GST_PAD_SETCAPSFUNC (pad);
 
-  /* set caps on pad if call succeeds */
-  res = gst_pad_set_caps (pad, caps);
-  /* no need to unref the caps here, set_caps takes a ref and
-   * our ref goes away when we leave this function. */
+  /* call setcaps function to configure the pad only if the
+   * caps is not NULL */
+  if (setcaps != NULL) {
+    if (!GST_PAD_IS_IN_SETCAPS (pad)) {
+      GST_OBJECT_FLAG_SET (pad, GST_PAD_IN_SETCAPS);
+      GST_OBJECT_UNLOCK (pad);
+      if (!setcaps (pad, caps))
+        goto setcaps_failed;
+      GST_OBJECT_LOCK (pad);
+      GST_OBJECT_FLAG_UNSET (pad, GST_PAD_IN_SETCAPS);
+    } else {
+      GST_CAT_DEBUG_OBJECT (GST_CAT_CAPS, pad, "pad was dispatching");
+    }
+  }
+  GST_OBJECT_UNLOCK (pad);
 
-  return res;
+  return TRUE;
 
-not_accepted:
+  /* ERRORS */
+setcaps_failed:
   {
-    GST_CAT_DEBUG_OBJECT (GST_CAT_CAPS, pad,
-        "caps %" GST_PTR_FORMAT " not accepted", caps);
     return FALSE;
   }
 }
 
-/* returns TRUE if the src pad could be configured to accept the given caps */
 static gboolean
-gst_pad_configure_src (GstPad * pad, GstCaps * caps, gboolean dosetcaps)
+gst_pad_configure_sink (GstPad * pad, GstCaps * caps)
 {
-  gboolean res;
+  /* See if pad accepts the caps */
+  if (!gst_caps_can_intersect (caps, gst_pad_get_pad_template_caps (pad)))
+    goto not_accepted;
 
-  if (dosetcaps) {
-    /* See if pad accepts the caps */
-    if (!gst_pad_accept_caps (pad, caps))
-      goto not_accepted;
+  if (!gst_pad_call_setcaps (pad, caps))
+    goto not_accepted;
 
-    res = gst_pad_set_caps (pad, caps);
-  } else {
-    res = TRUE;
-  }
-  return res;
+  return TRUE;
 
 not_accepted:
   {
@@ -2794,7 +2745,6 @@ gst_pad_get_allowed_caps (GstPad * pad)
   g_return_val_if_fail (GST_IS_PAD (pad), NULL);
 
   GST_OBJECT_LOCK (pad);
-
   peer = GST_PAD_PEER (pad);
   if (G_UNLIKELY (peer == NULL))
     goto no_peer;
@@ -2846,7 +2796,7 @@ no_peer:
 GstCaps *
 gst_pad_get_negotiated_caps (GstPad * pad)
 {
-  GstCaps *caps;
+  GstCaps *caps = NULL;
   GstPad *peer;
 
   g_return_val_if_fail (GST_IS_PAD (pad), NULL);
@@ -2858,9 +2808,9 @@ gst_pad_get_negotiated_caps (GstPad * pad)
 
   GST_CAT_DEBUG_OBJECT (GST_CAT_PROPERTIES, pad, "getting negotiated caps");
 
-  caps = GST_PAD_CAPS (pad);
-  if (caps)
+  if ((caps = get_pad_caps (pad)))
     gst_caps_ref (caps);
+
   GST_OBJECT_UNLOCK (pad);
 
   GST_CAT_DEBUG_OBJECT (GST_CAT_CAPS, pad, "negotiated caps %" GST_PTR_FORMAT,
@@ -2872,7 +2822,6 @@ no_peer:
   {
     GST_CAT_DEBUG_OBJECT (GST_CAT_PROPERTIES, pad, "no peer");
     GST_OBJECT_UNLOCK (pad);
-
     return NULL;
   }
 }
@@ -3465,24 +3414,6 @@ gst_pad_data_unref (gboolean is_buffer, void *data)
   }
 }
 
-static GstCaps *
-gst_pad_data_get_caps (gboolean is_buffer, void *data)
-{
-  GstCaps *caps;
-
-  if (G_LIKELY (is_buffer)) {
-    caps = GST_BUFFER_CAPS (data);
-  } else {
-    GstBuffer *buf;
-
-    if ((buf = gst_buffer_list_get (GST_BUFFER_LIST_CAST (data), 0)))
-      caps = GST_BUFFER_CAPS (buf);
-    else
-      caps = NULL;
-  }
-  return caps;
-}
-
 /* this is the chain function that does not perform the additional argument
  * checking for that little extra speed.
  */
@@ -3490,8 +3421,7 @@ static inline GstFlowReturn
 gst_pad_chain_data_unchecked (GstPad * pad, gboolean is_buffer, void *data,
     GstPadPushCache * cache)
 {
-  GstCaps *caps;
-  gboolean caps_changed, needs_events;
+  gboolean needs_events;
   GstFlowReturn ret;
   gboolean emit_signal;
   GstEvent *events[GST_EVENT_MAX_STICKY];
@@ -3502,9 +3432,6 @@ gst_pad_chain_data_unchecked (GstPad * pad, gboolean is_buffer, void *data,
   if (G_UNLIKELY (GST_PAD_IS_FLUSHING (pad)))
     goto flushing;
 
-  caps = gst_pad_data_get_caps (is_buffer, data);
-  caps_changed = caps && caps != GST_PAD_CAPS (pad);
-
   needs_events = GST_PAD_NEEDS_EVENTS (pad);
   if (G_UNLIKELY (needs_events)) {
     /* need to make a copy because when we release the object lock, things
@@ -3536,12 +3463,6 @@ gst_pad_chain_data_unchecked (GstPad * pad, gboolean is_buffer, void *data,
       goto context_error;
   }
 
-  if (G_UNLIKELY (caps_changed)) {
-    GST_DEBUG_OBJECT (pad, "caps changed to %p %" GST_PTR_FORMAT, caps, caps);
-    if (G_UNLIKELY (!gst_pad_configure_sink (pad, caps)))
-      goto not_negotiated;
-  }
-
   /* NOTE: we read the chainfunc unlocked.
    * we cannot hold the lock for the pad so we might send
    * the data to the wrong function. This is not really a
@@ -3559,7 +3480,6 @@ gst_pad_chain_data_unchecked (GstPad * pad, gboolean is_buffer, void *data,
 
     if (cache) {
       cache->peer = gst_object_ref (pad);
-      cache->caps = caps ? gst_caps_ref (caps) : NULL;
     }
 
     ret = chainfunc (pad, GST_BUFFER_CAST (data));
@@ -3639,14 +3559,6 @@ context_error:
     GST_PAD_STREAM_UNLOCK (pad);
     return ret;
   }
-not_negotiated:
-  {
-    gst_pad_data_unref (is_buffer, data);
-    GST_CAT_LOG_OBJECT (GST_CAT_SCHEDULING, pad,
-        "pushing data but pad did not accept");
-    GST_PAD_STREAM_UNLOCK (pad);
-    return GST_FLOW_NOT_NEGOTIATED;
-  }
 no_function:
   {
     gst_pad_data_unref (is_buffer, data);
@@ -3742,8 +3654,6 @@ gst_pad_push_data (GstPad * pad, gboolean is_buffer, void *data,
 {
   GstPad *peer;
   GstFlowReturn ret;
-  GstCaps *caps;
-  gboolean caps_changed;
 
   GST_OBJECT_LOCK (pad);
 
@@ -3775,24 +3685,10 @@ gst_pad_push_data (GstPad * pad, gboolean is_buffer, void *data,
   if (G_UNLIKELY ((peer = GST_PAD_PEER (pad)) == NULL))
     goto not_linked;
 
-  /* Before pushing the buffer to the peer pad, ensure that caps
-   * are set on this pad */
-  caps = gst_pad_data_get_caps (is_buffer, data);
-  caps_changed = caps && caps != GST_PAD_CAPS (pad);
-
   /* take ref to peer pad before releasing the lock */
   gst_object_ref (peer);
   GST_OBJECT_UNLOCK (pad);
 
-  /* we got a new datatype from the pad, it had better handle it */
-  if (G_UNLIKELY (caps_changed)) {
-    GST_DEBUG_OBJECT (pad,
-        "caps changed from %" GST_PTR_FORMAT " to %p %" GST_PTR_FORMAT,
-        GST_PAD_CAPS (pad), caps, caps);
-    if (G_UNLIKELY (!gst_pad_set_caps (pad, caps)))
-      goto not_negotiated;
-  }
-
   ret = gst_pad_chain_data_unchecked (peer, is_buffer, data, cache);
 
   gst_object_unref (peer);
@@ -3843,14 +3739,6 @@ not_linked:
     GST_OBJECT_UNLOCK (pad);
     return GST_FLOW_NOT_LINKED;
   }
-not_negotiated:
-  {
-    gst_pad_data_unref (is_buffer, data);
-    gst_object_unref (peer);
-    GST_CAT_DEBUG_OBJECT (GST_CAT_SCHEDULING, pad,
-        "element pushed data then refused to accept the caps");
-    return GST_FLOW_NOT_NEGOTIATED;
-  }
 }
 
 static inline GstPadPushCache *
@@ -3876,8 +3764,6 @@ static inline void
 pad_free_cache (GstPadPushCache * cache)
 {
   gst_object_unref (cache->peer);
-  if (cache->caps)
-    gst_caps_unref (cache->caps);
   g_slice_free (GstPadPushCache, cache);
 }
 
@@ -3957,7 +3843,6 @@ gst_pad_push (GstPad * pad, GstBuffer * buffer)
   GstFlowReturn ret;
   gpointer *cache_ptr;
   GstPad *peer;
-  GstCaps *caps;
 
   g_return_val_if_fail (GST_IS_PAD (pad), GST_FLOW_ERROR);
   g_return_val_if_fail (GST_PAD_IS_SRC (pad), GST_FLOW_ERROR);
@@ -3970,13 +3855,6 @@ gst_pad_push (GstPad * pad, GstBuffer * buffer)
   if (G_UNLIKELY (cache == NULL))
     goto slow_path;
 
-  /* check caps */
-  caps = GST_BUFFER_CAPS (buffer);
-  if (G_UNLIKELY (caps && caps != cache->caps)) {
-    pad_free_cache (cache);
-    goto slow_path;
-  }
-
   peer = cache->peer;
 
   GST_PAD_STREAM_LOCK (peer);
@@ -4069,12 +3947,10 @@ invalid:
 GstFlowReturn
 gst_pad_push_list (GstPad * pad, GstBufferList * list)
 {
-  GstBuffer *buf;
   GstPadPushCache *cache;
   GstFlowReturn ret;
   gpointer *cache_ptr;
   GstPad *peer;
-  GstCaps *caps;
 
   g_return_val_if_fail (GST_IS_PAD (pad), GST_FLOW_ERROR);
   g_return_val_if_fail (GST_PAD_IS_SRC (pad), GST_FLOW_ERROR);
@@ -4087,17 +3963,6 @@ gst_pad_push_list (GstPad * pad, GstBufferList * list)
   if (G_UNLIKELY (cache == NULL))
     goto slow_path;
 
-  /* check caps */
-  if ((buf = gst_buffer_list_get (list, 0)))
-    caps = GST_BUFFER_CAPS (buf);
-  else
-    caps = NULL;
-
-  if (G_UNLIKELY (caps && caps != cache->caps)) {
-    pad_free_cache (cache);
-    goto slow_path;
-  }
-
   peer = cache->peer;
 
   GST_PAD_STREAM_LOCK (peer);
@@ -4219,8 +4084,6 @@ gst_pad_get_range_unchecked (GstPad * pad, guint64 offset, guint size,
   GstFlowReturn ret;
   GstPadGetRangeFunction getrangefunc;
   gboolean emit_signal;
-  GstCaps *caps;
-  gboolean caps_changed;
 
   GST_PAD_STREAM_LOCK (pad);
 
@@ -4251,19 +4114,6 @@ gst_pad_get_range_unchecked (GstPad * pad, guint64 offset, guint size,
   if (G_UNLIKELY (ret != GST_FLOW_OK))
     goto get_range_failed;
 
-  GST_OBJECT_LOCK (pad);
-  /* Before pushing the buffer to the peer pad, ensure that caps
-   * are set on this pad */
-  caps = GST_BUFFER_CAPS (*buffer);
-  caps_changed = caps && caps != GST_PAD_CAPS (pad);
-  GST_OBJECT_UNLOCK (pad);
-
-  if (G_UNLIKELY (caps_changed)) {
-    GST_DEBUG_OBJECT (pad, "caps changed to %p %" GST_PTR_FORMAT, caps, caps);
-    /* this should usually work because the element produced the buffer */
-    if (G_UNLIKELY (!gst_pad_configure_src (pad, caps, TRUE)))
-      goto not_negotiated;
-  }
   return ret;
 
   /* ERRORS */
@@ -4300,14 +4150,6 @@ get_range_failed:
         pad, "getrange failed, flow: %s", gst_flow_get_name (ret));
     return ret;
   }
-not_negotiated:
-  {
-    gst_buffer_unref (*buffer);
-    *buffer = NULL;
-    GST_CAT_WARNING_OBJECT (GST_CAT_SCHEDULING, pad,
-        "getrange returned buffer of unaccaptable caps");
-    return GST_FLOW_NOT_NEGOTIATED;
-  }
 }
 
 /**
@@ -4380,8 +4222,7 @@ gst_pad_pull_range (GstPad * pad, guint64 offset, guint size,
   GstPad *peer;
   GstFlowReturn ret;
   gboolean emit_signal;
-  GstCaps *caps;
-  gboolean caps_changed, needs_events;
+  gboolean needs_events;
   GstEvent *events[GST_EVENT_MAX_STICKY];
 
   g_return_val_if_fail (GST_IS_PAD (pad), GST_FLOW_ERROR);
@@ -4417,10 +4258,6 @@ gst_pad_pull_range (GstPad * pad, guint64 offset, guint size,
   }
 
   GST_OBJECT_LOCK (pad);
-  /* Before pushing the buffer to the peer pad, ensure that caps
-   * are set on this pad */
-  caps = GST_BUFFER_CAPS (*buffer);
-  caps_changed = caps && caps != GST_PAD_CAPS (pad);
 
   needs_events = GST_PAD_NEEDS_EVENTS (pad);
   if (G_UNLIKELY (needs_events)) {
@@ -4436,13 +4273,6 @@ gst_pad_pull_range (GstPad * pad, guint64 offset, guint size,
       goto events_error;
   }
 
-  /* we got a new datatype on the pad, see if it can handle it */
-  /* we got a new datatype on the pad, see if it can handle it */
-  if (G_UNLIKELY (caps_changed)) {
-    GST_DEBUG_OBJECT (pad, "caps changed to %p %" GST_PTR_FORMAT, caps, caps);
-    if (G_UNLIKELY (!gst_pad_configure_sink (pad, caps)))
-      goto not_negotiated;
-  }
   return ret;
 
   /* ERROR recovery here */
@@ -4477,14 +4307,6 @@ events_error:
         "pullrange returned events that were not accepted");
     return ret;
   }
-not_negotiated:
-  {
-    gst_buffer_unref (*buffer);
-    *buffer = NULL;
-    GST_CAT_WARNING_OBJECT (GST_CAT_SCHEDULING, pad,
-        "pullrange returned buffer of different caps");
-    return GST_FLOW_NOT_NEGOTIATED;
-  }
 }
 
 /**
@@ -4576,13 +4398,21 @@ gst_pad_push_event (GstPad * pad, GstEvent * event)
     gst_event_replace (&pad->priv->events[idx], event);
   }
 
-  peerpad = GST_PAD_PEER (pad);
+  if ((peerpad = GST_PAD_PEER (pad)))
+    gst_object_ref (peerpad);
+  GST_OBJECT_UNLOCK (pad);
+
+  /* backwards compatibility mode for caps */
+  if (GST_EVENT_TYPE (event) == GST_EVENT_CAPS) {
+    GstCaps *caps;
+    gst_event_parse_caps (event, &caps);
+    gst_pad_call_setcaps (pad, caps);
+  }
+
+  /* now check the peer pad */
   if (peerpad == NULL)
     goto not_linked;
 
-  gst_object_ref (peerpad);
-  GST_OBJECT_UNLOCK (pad);
-
   GST_LOG_OBJECT (pad, "sending event %s to peerpad %" GST_PTR_FORMAT,
       GST_EVENT_TYPE_NAME (event), peerpad);
 
@@ -4607,7 +4437,6 @@ not_linked:
   {
     GST_DEBUG_OBJECT (pad, "Dropping event because pad is not linked");
     gst_event_unref (event);
-    GST_OBJECT_UNLOCK (pad);
     return FALSE;
   }
 flushed:
@@ -4762,6 +4591,13 @@ gst_pad_send_event (GstPad * pad, GstEvent * event)
     result = eventfunc (pad, event);
   }
 
+  /* backwards compatibility mode for caps */
+  if (GST_EVENT_TYPE (event) == GST_EVENT_CAPS) {
+    GstCaps *caps;
+    gst_event_parse_caps (event, &caps);
+    gst_pad_configure_sink (pad, caps);
+  }
+
   if (need_unlock)
     GST_PAD_STREAM_UNLOCK (pad);