Use the helper BufferWriter to optionally write frames to disk as they are captured. Signed-off-by: Niklas Söderlund <niklas.soderlund@ragnatech.se> Signed-off-by: Jacopo Mondi <jacopo@jmondi.org> Signed-off-by: Kieran Bingham <kieran.bingham@ideasonboard.com> Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>