From what I see there is no "Contrast" effect, you may try those other effect such as Punch/Expand Contrast etc that change the colors. But, if that don't get to what you're trying to get to. You might need to adjust the video contrast by using a video editor.
From my observation, in my system, the video play within my Media Player classics vs play by Deskscape have very similar/no change color level. Maybe try changing video codec and/or change different video setting as I mentioned on your thread here: https://forums.stardock.com/532101/get;3950423
Thank you,
Basj,
Stardock Community Assistant