This format was added but not documented. Do this now.
Signed-off-by: NHans Verkuil <hans.verkuil@cisco.com>
Acked-by: NRicardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab@osg.samsung.com>