vaapidecodebin: enable vpp if it is available

Instead of creating and adding VPP into the bin at setup, we wait until
we are sure the VA driver supports it. We know that when the VA video
context is received by the bin. Afterwards, it is decided to instanciate
and link the VPP or not.

This is more efficient and safer than waiting the VPP to fail and then
disable it.

https://bugzilla.gnome.org/show_bug.cgi?id=749554

2 files changed, 124 insertions, 59 deletions

diff --git a/gst/vaapi/gstvaapidecodebin.c b/gst/vaapi/gstvaapidecodebin.c
index ad814e77..f147f1c5 100644
--- a/gst/vaapi/gstvaapidecodebin.c
+++ b/gst/vaapi/gstvaapidecodebin.c
@@ -27,6 +27,7 @@
 #include <gst/pbutils/pbutils.h>
 #include "gstvaapipluginutil.h"
 #include "gstvaapidecodebin.h"
+#include "gstvaapivideocontext.h"
 
 #define GST_PLUGIN_NAME "vaapidecodebin"
 #define GST_PLUGIN_DESC "A Bin of VA-API elements: vaapidecode ! queue ! vaapipostproc"
@@ -101,30 +102,73 @@ GST_STATIC_PAD_TEMPLATE ("src",
 
 G_DEFINE_TYPE (GstVaapiDecodeBin, gst_vaapi_decode_bin, GST_TYPE_BIN);
 
-/* Remove the vaapipostproc if already added and reset the ghost pad target */
 static void
-disable_vpp (GstVaapiDecodeBin * vaapidecbin)
+post_missing_element_message (GstVaapiDecodeBin * vaapidecbin,
+    const gchar * missing_factory)
 {
-  GstPad *pad;
-  GstStateChangeReturn ret;
-  GstState state;
-
-  /*Fixme: Add run-time disabling support */
-  ret =
-      gst_element_get_state (GST_ELEMENT (vaapidecbin), &state, NULL,
-      GST_CLOCK_TIME_NONE);
-  if (ret != GST_STATE_CHANGE_SUCCESS || state > GST_STATE_NULL) {
-    GST_WARNING_OBJECT (vaapidecbin, "Failed to set disable-vpp property!,,"
-        "No support for run-time disabling, Ignoring the user request to disable VPP.");
-    return;
+  GstMessage *msg;
+
+  GST_ERROR_OBJECT (vaapidecbin, "Failed to create %s element",
+      missing_factory);
+  msg =
+      gst_missing_element_message_new (GST_ELEMENT_CAST (vaapidecbin),
+      missing_factory);
+  gst_element_post_message (GST_ELEMENT_CAST (vaapidecbin), msg);
+}
+
+static gboolean
+activate_vpp (GstVaapiDecodeBin * vaapidecbin)
+{
+  GstElement *src;
+
+  if (vaapidecbin->ghost_pad_src || vaapidecbin->postproc)
+    return TRUE;
+
+  if (!vaapidecbin->has_vpp || vaapidecbin->disable_vpp) {
+    src = vaapidecbin->queue;
+    goto connect_src_ghost_pad;
   }
 
-  gst_element_set_state (vaapidecbin->postproc, GST_STATE_NULL);
-  gst_bin_remove (GST_BIN (vaapidecbin), vaapidecbin->postproc);
+  /* create the postproc */
+  vaapidecbin->postproc =
+      gst_element_factory_make ("vaapipostproc", "vaapipostproc");
+  if (!vaapidecbin->postproc)
+    goto error_element_missing;
+
+  g_object_set (G_OBJECT (vaapidecbin->postproc), "deinterlace-method",
+      vaapidecbin->deinterlace_method, NULL);
+
+  gst_bin_add (GST_BIN (vaapidecbin), vaapidecbin->postproc);
+  if (!gst_element_link_pads_full (vaapidecbin->queue, "src",
+          vaapidecbin->postproc, "sink", GST_PAD_LINK_CHECK_NOTHING))
+    goto error_link_pad;
+
+  GST_DEBUG_OBJECT (vaapidecbin, "Enabling VPP");
+  src = vaapidecbin->postproc;
 
-  pad = gst_element_get_static_pad (GST_ELEMENT (vaapidecbin->queue), "src");
-  gst_ghost_pad_set_target ((GstGhostPad *) vaapidecbin->ghost_pad_src, pad);
-  gst_object_unref (pad);
+  goto connect_src_ghost_pad;
+
+error_element_missing:
+  {
+    post_missing_element_message (vaapidecbin, "vaapipostproc");
+    return FALSE;
+  }
+error_link_pad:
+  {
+    GST_ERROR_OBJECT (vaapidecbin, "Failed to link the child elements");
+    return FALSE;
+  }
+connect_src_ghost_pad:
+  {
+    GstPad *srcpad, *ghostpad;
+
+    srcpad = gst_element_get_static_pad (src, "src");
+    ghostpad = gst_ghost_pad_new ("src", srcpad);
+    vaapidecbin->ghost_pad_src = ghostpad;
+    gst_object_unref (srcpad);
+    gst_element_add_pad (GST_ELEMENT (vaapidecbin), ghostpad);
+    return TRUE;
+  }
 }
 
 static void
@@ -155,11 +199,19 @@ gst_vaapi_decode_bin_set_property (GObject * object,
           vaapidecbin->deinterlace_method, NULL);
       break;
     case PROP_DISABLE_VPP:
-      vaapidecbin->disable_vpp = g_value_get_boolean (value);
-      /* Remove the vaapipostpro */
-      if (vaapidecbin->disable_vpp && vaapidecbin->postproc)
-        disable_vpp (vaapidecbin);
+    {
+      gboolean disable_vpp;
+
+      disable_vpp = g_value_get_boolean (value);
+      if (!disable_vpp && !vaapidecbin->has_vpp)
+        GST_WARNING_OBJECT (vaapidecbin,
+            "Cannot enable VPP since the VA driver does not support it");
+      else
+        vaapidecbin->disable_vpp = disable_vpp;
+
+      /* @TODO: Add run-time disabling support */
       break;
+    }
     default:
       G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
       break;
@@ -195,17 +247,61 @@ gst_vaapi_decode_bin_get_property (GObject * object,
 }
 
 static void
+gst_vaapi_decode_bin_handle_message (GstBin * bin, GstMessage * message)
+{
+  GstVaapiDecodeBin *vaapidecbin = GST_VAAPI_DECODE_BIN (bin);
+  GstMessageType type;
+  GstContext *context = NULL;
+  const gchar *context_type;
+  GstVaapiDisplay *display = NULL;
+
+  type = GST_MESSAGE_TYPE (message);
+  if (type != GST_MESSAGE_HAVE_CONTEXT)
+    goto bail;
+  gst_message_parse_have_context (message, &context);
+  if (!context)
+    goto bail;
+  context_type = gst_context_get_context_type (context);
+  if (g_strcmp0 (context_type, GST_VAAPI_DISPLAY_CONTEXT_TYPE_NAME) != 0)
+    goto bail;
+  if (!gst_vaapi_video_context_get_display (context, &display))
+    goto bail;
+
+  vaapidecbin->has_vpp = gst_vaapi_display_has_video_processing (display);
+
+  /* the underlying VA driver implementation doesn't support video
+   * post-processing, hence we have to disable it */
+  if (!vaapidecbin->has_vpp) {
+    GST_WARNING_OBJECT (vaapidecbin, "VA driver doesn't support VPP");
+    if (!vaapidecbin->disable_vpp) {
+      vaapidecbin->disable_vpp = TRUE;
+    }
+  }
+
+  activate_vpp (vaapidecbin);
+
+bail:
+  GST_BIN_CLASS (gst_vaapi_decode_bin_parent_class)->handle_message (bin,
+      message);
+}
+
+static void
 gst_vaapi_decode_bin_class_init (GstVaapiDecodeBinClass * klass)
 {
   GObjectClass *gobject_class;
   GstElementClass *element_class;
+  GstBinClass *bin_class;
 
   gobject_class = G_OBJECT_CLASS (klass);
   element_class = GST_ELEMENT_CLASS (klass);
+  bin_class = GST_BIN_CLASS (klass);
 
   gobject_class->set_property = gst_vaapi_decode_bin_set_property;
   gobject_class->get_property = gst_vaapi_decode_bin_get_property;
 
+  bin_class->handle_message =
+      GST_DEBUG_FUNCPTR (gst_vaapi_decode_bin_handle_message);
+
   gst_element_class_set_static_metadata (element_class,
       "VA-API Decode Bin",
       "Codec/Decoder/Video",
@@ -279,35 +375,11 @@ gst_vaapi_decode_bin_configure (GstVaapiDecodeBin * vaapidecbin)
           vaapidecbin->queue, "sink", GST_PAD_LINK_CHECK_NOTHING))
     goto error_link_pad;
 
-  if (!vaapidecbin->disable_vpp) {
-    /* create the postproc */
-    vaapidecbin->postproc =
-        gst_element_factory_make ("vaapipostproc", "vaapipostproc");
-    if (!vaapidecbin->postproc) {
-      missing_factory = "vaapipostproc";
-      goto error_element_missing;
-    }
-
-    g_object_set (G_OBJECT (vaapidecbin->postproc),
-        "deinterlace-method", vaapidecbin->deinterlace_method, NULL);
-
-    gst_bin_add (GST_BIN (vaapidecbin), vaapidecbin->postproc);
-    if (!gst_element_link_pads_full (vaapidecbin->queue, "src",
-            vaapidecbin->postproc, "sink", GST_PAD_LINK_CHECK_NOTHING))
-      goto error_link_pad;
-  }
-
   return TRUE;
 
 error_element_missing:
   {
-    GstMessage *msg;
-    GST_ERROR_OBJECT (vaapidecbin, "Failed to create %s element",
-        missing_factory);
-    msg =
-        gst_missing_element_message_new (GST_ELEMENT_CAST (vaapidecbin),
-        missing_factory);
-    gst_element_post_message (GST_ELEMENT_CAST (vaapidecbin), msg);
+    post_missing_element_message (vaapidecbin, missing_factory);
     return FALSE;
   }
 error_link_pad:
@@ -321,7 +393,9 @@ static void
 gst_vaapi_decode_bin_init (GstVaapiDecodeBin * vaapidecbin)
 {
   GstPad *element_pad, *ghost_pad;
-  GstElement *src_element;
+
+  /* let's assume we have VPP until we prove the opposite */
+  vaapidecbin->has_vpp = TRUE;
 
   if (!gst_vaapi_decode_bin_configure (vaapidecbin))
     return;
@@ -334,14 +408,4 @@ gst_vaapi_decode_bin_init (GstVaapiDecodeBin * vaapidecbin)
       GST_PAD_PAD_TEMPLATE (element_pad));
   gst_object_unref (element_pad);
   gst_element_add_pad (GST_ELEMENT (vaapidecbin), ghost_pad);
-
-  /* create ghost pad src */
-  src_element =
-      vaapidecbin->disable_vpp ? vaapidecbin->queue : vaapidecbin->postproc;
-  element_pad = gst_element_get_static_pad (GST_ELEMENT (src_element), "src");
-
-  ghost_pad = gst_ghost_pad_new ("src", element_pad);
-  vaapidecbin->ghost_pad_src = ghost_pad;
-  gst_object_unref (element_pad);
-  gst_element_add_pad (GST_ELEMENT (vaapidecbin), ghost_pad);
 }
diff --git a/gst/vaapi/gstvaapidecodebin.h b/gst/vaapi/gstvaapidecodebin.h
index a5c8b876..0f3fb6cd 100644
--- a/gst/vaapi/gstvaapidecodebin.h
+++ b/gst/vaapi/gstvaapidecodebin.h
@@ -55,6 +55,7 @@ typedef struct _GstVaapiDecodeBin {
   guint64 max_size_time;
   GstVaapiDeinterlaceMethod deinterlace_method;
   gboolean disable_vpp;
+  gboolean has_vpp;
 
 } GstVaapiDecodeBin;