ratecontrol: cleanup, replace (unnecessary) constant arrays with constants.
level: fix MinGW warning

--HG--
extra : rebase_source : cc2f8188c3ad5ff9d25fa334d6da446cb7909f78
extra : amend_source : 8b0a4553eaeff84fdf8c3b1d4b3baf91c2cfefd4