On some videos, it looks darker dan the original

I noticed this when I'm doing screencast the other day and played the result on MPC (in mp4). But the colors look darker, it's very noticable especially when you look at the white color. I've tried playing the video on VLC, Chrome, and Windows 10's Movie. It looks fine on all three, only MPC shows darker color.

Now, this only happen on some videos. When I tried playing some other videos, nothing wrong with the color. So, if I change the brightness and contrast to fix some of the videos that look dark, then the others will look bad.

Is there any solution to this?

Does white look like light grey and pure black like dark grey?

Can you copy the MediaInfo details for one of the files that gives problems?