Make GstVaapiVideoBuffer a simple wrapper for video meta. This buffer is
no longer necessary but for compatibility with GStreamer 0.10 APIs or users
expecting a GstSurfaceBuffer like Clutter.
This is a preferred thread-safe version. Also add an inline version of
g_clear_object() if compiling with glib < 2.28.
Signed-off-by: Gwenole Beauchesne <gwenole.beauchesne@intel.com>
Allow rendering flags, as a combination of GstVaapiSurfaceRenderFlags,
to be set to the video buffer. In particular, this is mostly useful for
basic deinterlacing.
