videotoolbox: various small improvements, bug fixes and cleanup
videotoolbox: various small improvements, bug fixes and cleanup

vlc-mirror/vlc,xkfz007/vlc,vlc-mirror/vlc,vlc-mirror/vlc,shyamalschandra/vlc,shyamalschandra/vlc,vlc-mirror/vlc,xkfz007/vlc,shyamalschandra/vlc,xkfz007/vlc,vlc-mirror/vlc,xkfz007/vlc,vlc-mirror/vlc,xkfz007/vlc,vlc-mirror/vlc,xkfz007/vlc,xkfz007/vlc,shyamalschandra/vlc,shyamalschandra/vlc,shyamalschandra/vlc,shyamalschandra/vlc