From 7d9044cf05fd82d704feee7ed945bc89ba31a45f Mon Sep 17 00:00:00 2001
From: Matthew Waters <matthew@centricular.com>
Date: Thu, 23 Oct 2014 23:55:48 +1100
Subject: [PATCH] glmixer: override the accept caps query in order to 'convert'
 capsfeatures

Otherwise, it is only possible for the sink pads and the src pads to
have the exact same caps features.  We can convert from any feature
to another feature so support that.
---
 ext/gl/gstglmixer.c | 30 ++++++++++++++++++++++++++++++
 1 file changed, 30 insertions(+)

diff --git a/ext/gl/gstglmixer.c b/ext/gl/gstglmixer.c
index 743bacc90b..da6ba67ed0 100644
--- a/ext/gl/gstglmixer.c
+++ b/ext/gl/gstglmixer.c
@@ -267,6 +267,26 @@ context_error:
   }
 }
 
+static gboolean
+gst_gl_mixer_pad_sink_acceptcaps (GstPad * pad, GstGLMixer * mix,
+    GstCaps * caps)
+{
+  gboolean ret;
+  GstCaps *template_caps;
+
+  GST_DEBUG_OBJECT (pad, "try accept caps of %" GST_PTR_FORMAT, caps);
+
+  template_caps = gst_pad_get_pad_template_caps (pad);
+  template_caps = gst_caps_make_writable (template_caps);
+
+  ret = gst_caps_can_intersect (caps, template_caps);
+  GST_DEBUG_OBJECT (pad, "%saccepted caps %" GST_PTR_FORMAT,
+      (ret ? "" : "not "), caps);
+  gst_caps_unref (template_caps);
+
+  return ret;
+}
+
 static gboolean
 gst_gl_mixer_sink_query (GstAggregator * agg, GstAggregatorPad * bpad,
     GstQuery * query)
@@ -277,6 +297,16 @@ gst_gl_mixer_sink_query (GstAggregator * agg, GstAggregatorPad * bpad,
   GST_TRACE ("QUERY %" GST_PTR_FORMAT, query);
 
   switch (GST_QUERY_TYPE (query)) {
+    case GST_QUERY_ACCEPT_CAPS:
+    {
+      GstCaps *caps;
+
+      gst_query_parse_accept_caps (query, &caps);
+      ret = gst_gl_mixer_pad_sink_acceptcaps (GST_PAD (bpad), mix, caps);
+      gst_query_set_accept_caps_result (query, ret);
+      ret = TRUE;
+      break;
+    }
     case GST_QUERY_ALLOCATION:
     {
       GstQuery *decide_query = NULL;