/* NULL pointers are no correct GstCaps */
g_return_val_if_fail (caps1 != NULL, NULL);
g_return_val_if_fail (caps2 != NULL, NULL);
if (CAPS_IS_EMPTY (caps1))
/* NULL pointers are no correct GstCaps */
g_return_val_if_fail (caps1 != NULL, NULL);
g_return_val_if_fail (caps2 != NULL, NULL);
if (CAPS_IS_EMPTY (caps1))