why –no-mbtree? maybe it’s too short?
Your x264 settings are stupid for such low bitrate. First you shouldn’t mess with settings which you don’t know how to use (I am hinting at “–no-mbtree –direct spatial –no-dct-decimate”). Second you should disable psy-rd at such low bitrates.
Here [URL]http://rghost.ru/6YCWSVw6b[/URL] is encode with “–crf 33 –preset placebo –psy-rd 0” settings and 96.6 KB size.