You have rightly pointed out the issue. Point no 2 has a great impact in change of color. I have three different screenshots.
1st one is the AECS Composition Window.
2nd is the H.264 conversion in AECS5.5 and Played in WMP
3rd is the H.264 conversion in AECS5.5 and Played in VLC
Now it may be clear to the novice shooters like me.