is there a luminosity flattener?

[Katie Boundary]

basically is there a filter that takes slightly less black parts of black areas and turns them dark gray, and turns slightly less white parts of all-white areas and turns them noticeably light gray?

[Sharc]

basically is there a filter that takes slightly less black parts of black areas and turns them dark gray, and turns slightly less white parts of all-white areas and turns them noticeably light gray?
Gamma adjustment?
Levels adjustment?
ColorYUV?

[Mounir]

try autoadjust (must be tuned)

AutoAdjust(auto_gain=true,gain_mode=1,avg_safety=1.00,scd_threshold=0,input_tv=false,output_tv=true,dark_limit=1.0,bright_limit=1.15,gamma_limit =1.0,dark_exclude=1.00,temporal_radius=5,high_quality=true,high_bitdepth=false)