vaapipostproc: element warning if video direction is unsupported

If the video direction is unsupported by the driver, an element
warning is posted in the bus to notify the application.

gst_vaapi_enum_type_get_nick() was added in the library thus it can
be used elsewhere. It retrives the nick from an enum gtype.

gst-libs/gst/vaapi/gstvaapifilter.c

@@ -118,17 +118,6 @@ gst_vaapi_scale_method_get_type (void)
   return g_type;
 }
 
-static const gchar *
-gst_vaapi_get_video_direction_nick (GstVideoOrientationMethod method)
-{
-  gpointer const klass = g_type_class_peek (GST_TYPE_VIDEO_ORIENTATION_METHOD);
-  GEnumValue *const e = g_enum_get_value (klass, method);
-
-  if (e)
-    return e->value_nick;
-  return "<unknown>";
-}
-
 GType
 gst_vaapi_deinterlace_method_get_type (void)
 {
@@ -1996,23 +1985,15 @@ gst_vaapi_filter_set_video_direction (GstVaapiFilter * filter,
 
     from_GstVideoOrientationMethod (method, &va_mirror, &va_rotation);
 
-    if (va_mirror != VA_MIRROR_NONE && !(filter->mirror_flags & va_mirror)) {
+    if (va_mirror != VA_MIRROR_NONE && !(filter->mirror_flags & va_mirror))
-      GST_WARNING ("%s video-direction unsupported",
+      return FALSE;
-          gst_vaapi_get_video_direction_nick (method));
-      return TRUE;
-    }
 
     if (va_rotation != VA_ROTATION_NONE
-        && !(filter->rotation_flags & (1 << va_rotation))) {
+        && !(filter->rotation_flags & (1 << va_rotation)))
-      GST_WARNING ("%s video-direction unsupported",
+      return FALSE;
-          gst_vaapi_get_video_direction_nick (method));
-      return TRUE;
-    }
   }
 #else
-  GST_WARNING ("%s video-direction unsupported",
+  return FALSE;
-      gst_vaapi_get_video_direction_nick (method));
-  return TRUE;
 #endif
 
   filter->video_direction = method;

gst-libs/gst/vaapi/gstvaapivalue.c

@@ -215,3 +215,22 @@ gst_vaapi_type_define_enum_subset_from_mask (GstVaapiEnumSubset * subset,
   }
   return subset->type;
 }
+
+/**
+ * gst_vaapi_enum_type_get_nick:
+ * @type: an enum #GType
+ * @value: the value to get its nick
+ *
+ * Returns: (tranfer none); the string associated with
+ *   @value. Otherwise "<unknown>"
+ **/
+const gchar *
+gst_vaapi_enum_type_get_nick (GType type, gint value)
+{
+  gpointer const klass = g_type_class_peek (type);
+  GEnumValue *const e = g_enum_get_value (klass, value);
+
+  if (e)
+    return e->value_nick;
+  return "<unknown>";
+}

gst-libs/gst/vaapi/gstvaapivalue.h

@@ -157,6 +157,10 @@ G_PASTE(name,_get_type)(void)                                           \
     return gst_vaapi_type_define_enum_subset_from_mask(&subset, MASK);  \
 }
 
+G_GNUC_INTERNAL
+const gchar *
+gst_vaapi_enum_type_get_nick (GType type, gint value);
+
 G_END_DECLS
 
 #endif /* GST_VAAPI_VALUE_H */

gst/vaapi/gstvaapipostproc.c

@@ -37,6 +37,8 @@
 #include "gstcompat.h"
 #include <gst/video/video.h>
 
+#include <gst/vaapi/gstvaapivalue.h>
+
 #include "gstvaapipostproc.h"
 #include "gstvaapipostprocutil.h"
 #include "gstvaapipluginutil.h"
@@ -595,8 +597,15 @@ update_filter (GstVaapiPostproc * postproc)
 
   if (postproc->flags & GST_VAAPI_POSTPROC_FLAG_VIDEO_DIRECTION) {
     if (!gst_vaapi_filter_set_video_direction (postproc->filter,
-            postproc->video_direction))
+            postproc->video_direction)) {
-      return FALSE;
+      GST_ELEMENT_WARNING (postproc, LIBRARY, SETTINGS,
+          ("Unsupported video direction '%s' by driver.",
+              gst_vaapi_enum_type_get_nick
+              (GST_TYPE_VIDEO_ORIENTATION_METHOD, postproc->video_direction)),
+          ("video direction transformation ignored"));
+
+      /* Don't return FALSE because other filters might be set */
+    }
 
     if (gst_vaapi_filter_get_video_direction_default (postproc->filter) ==
         postproc->video_direction)