Videobuf is a moderately complex API which most V4L2 drivers should use,
but its documentation is...sparse.  This document attempts to improve the
situation.
Signed-off-by: NJonathan Corbet <corbet@lwn.net>
Reviewed-by: NRandy Dunlap <rdunlap@xenotime.net>
Signed-off-by: NMauro Carvalho Chehab <mchehab@redhat.com>