vaapiencode: h264: verify if requested profile is supported

Check if the requested profile in source caps, is supported by the
VA driver. If it is not, an info log message is send saying that
another (compatible?) profile will be used.

https://bugzilla.gnome.org/show_bug.cgi?id=757941

gst/vaapi/gstvaapiencode_h264.c

@@ -170,6 +170,9 @@ gst_vaapiencode_h264_init (GstVaapiEncodeH264 * encode)
 static void
 gst_vaapiencode_h264_finalize (GObject * object)
 {
+  GstVaapiEncodeH264 *const encode = GST_VAAPIENCODE_H264_CAST (object);
+
+  gst_caps_replace (&encode->available_caps, NULL);
   G_OBJECT_CLASS (gst_vaapiencode_h264_parent_class)->finalize (object);
 }
 
@@ -278,6 +281,51 @@ find_best_profile (GstCaps * caps)
   return data.best_profile;
 }
 
+static GstCaps *
+get_available_caps (GstVaapiEncodeH264 * encode)
+{
+  GstCaps *out_caps;
+  GArray *profiles;
+  GstVaapiProfile profile;
+  const gchar *profile_str;
+  GValue profile_v = G_VALUE_INIT;
+  GValue profile_list = G_VALUE_INIT;
+  guint i;
+
+  if (encode->available_caps)
+    return encode->available_caps;
+
+  g_value_init (&profile_list, GST_TYPE_LIST);
+  g_value_init (&profile_v, G_TYPE_STRING);
+
+  profiles =
+      gst_vaapi_display_get_encode_profiles
+      (GST_VAAPI_PLUGIN_BASE_DISPLAY (encode));
+  if (!profiles)
+    return NULL;
+
+  for (i = 0; i < profiles->len; i++) {
+    profile = g_array_index (profiles, GstVaapiProfile, i);
+    if (gst_vaapi_profile_get_codec (profile) != GST_VAAPI_CODEC_H264)
+      continue;
+    profile_str = gst_vaapi_profile_get_name (profile);
+    if (!profile_str)
+      continue;
+    g_value_set_string (&profile_v, profile_str);
+    gst_value_list_append_value (&profile_list, &profile_v);
+  }
+  g_array_unref (profiles);
+
+  out_caps = gst_caps_from_string (GST_CODEC_CAPS);
+  gst_caps_set_value (out_caps, "profile", &profile_list);
+  g_value_unset (&profile_list);
+  g_value_unset (&profile_v);
+
+  encode->available_caps = out_caps;
+
+  return encode->available_caps;
+}
+
 static gboolean
 gst_vaapiencode_h264_set_config (GstVaapiEncode * base_encode)
 {
@@ -310,6 +358,18 @@ gst_vaapiencode_h264_set_config (GstVaapiEncode * base_encode)
     GstStructure *structure;
     guint i, num_structures;
     GstVaapiProfile profile;
+    GstCaps *available_caps;
+
+    available_caps = get_available_caps (encode);
+    if (!available_caps) {
+      gst_caps_unref (template_caps);
+      gst_caps_unref (allowed_caps);
+      return FALSE;
+    }
+    if (!gst_caps_can_intersect (allowed_caps, available_caps)) {
+      GST_INFO_OBJECT (encode, "downstream requested an unsupported profile, "
+          "but encoder will output a compatible one");
+    }
 
     /* Check whether "stream-format" is avcC mode */
     num_structures = gst_caps_get_size (allowed_caps);

gst/vaapi/gstvaapiencode_h264.h

@@ -56,6 +56,7 @@ struct _GstVaapiEncodeH264
   GstVaapiEncode parent_instance;
 
   guint is_avc:1; /* [FALSE]=byte-stream (default); [TRUE]=avcC */
+  GstCaps *available_caps;
 };
 
 struct _GstVaapiEncodeH264Class