We add a GetConvergenceFrames method to the AgcAlgorithm class which can be called when the AGC is started from scratch. It suggests how many frames should be dropped before displaying any (while the AGC converges). The Raspberry Pi specific implementation makes this customisable from the tuning file. Signed-off-by: David Plowman <david.plowman@raspberrypi.com> Reviewed-by: Naushir Patuck <naush@raspberrypi.com> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>