FCPX and Youtube/ VLC gamma shift ??

Hi guys,
I read a lot already but couldn't really find a good solution to my problem:


After exporting my video it looks perfect in quicktime (same as it does in FCPX) but different in VLC and after uploading on youtube it is also darker!






1st image: preview on my macbook pro, fcpx, quicktime
2nd image: youtube
3rd image: vlc

What setting are needed in COMPRESSOR that my working material (1st image) will look the same on youtube..?


Any ideas?


I've change compressor settings like gamma to 0.90 or color settings as hd (709),... but not really major progress..


Thanks!


quick workflow: canon 5d iii - h.264 - fcpx - compressor - youtube