[age]

Just insert the path to the file, the function use the metadata but if missing they should be added manually :-)
The required plugin is vapoursynth-tonemap

import easytm
import vapoursynth as vs
core = vs.get_core()

c = core.ffms2.Source(source = 'C:/Users/.../video.mp4') 

c=easytm.mobius(c,target_nits=100,masterdisplay=None,transfer=None,matrix=None,primaries=None,resize_1080p=True)

c.set_output()

The operators are mobius, reinhard, hable and bt2390test

The bt.2390 display mapping operator works for now in rgb and it assume black point=0

This is the code used, honestly i'm not sure it's right and i have modified the way KS is calculated

import vapoursynth as vs

core = vs.get_core()
c = core.ffms2.Source(source = 'C:/Users/.../videos.mp4')


def bt2390test(clip="",masterdisplay=None,target_nits="",transfer=None,matrix=None,primaries=None ) :
    core = vs.get_core()
    c=clip
    
    if masterdisplay is None:
       masterdisplay=c.get_frame(0).props.MasteringDisplayMaxLuminance
    if transfer is None:  
       transfer=c.get_frame(0).props._Transfer
    if matrix is None:    
       matrix=c.get_frame(0).props._Matrix
    if transfer == 16 :
       transfer = "st2084"
    if transfer == 18 :   
       transfer = "std-b67"
    if matrix == 9 :
       matrix = "2020ncl"   
    if primaries is None:  
       primaries=c.get_frame(0).props._Primaries
    if primaries == 9 :
       primaries = "2020"
    if primaries == 1 :
       primaries = "709" 
       
       
 
    source_peak=masterdisplay
    matrix_in_s=matrix
    transfer_in_s=transfer
    


    source_peak=source_peak 


    
    
    
    c=core.resize.Bicubic(clip=c, format=vs.RGBS, filter_param_a=0, filter_param_b=0.75, matrix_in_s=matrix_in_s,chromaloc_in_s="center",chromaloc_s="center", range_in_s="limited", range_s="full",dither_type="none")


    lw = source_peak/10000   
    #eotf^-1  y=((x^0.1593017578125) * 18.8515625 + 0.8359375  /   (x^0.1593017578125) * 18.6875 + 1)^78.84375
    lw = ((((lw ** 0.1593017578125) * 18.8515625) + 0.8359375)  /   (((lw ** 0.1593017578125) * 18.6875) + 1))**78.84375

    
    lmax=target_nits/10000
    #eotf^-1  y=((x^0.1593017578125) * 18.8515625 + 0.8359375  /   (x^0.1593017578125) * 18.6875 + 1)^78.84375
    lmax = ((((lmax ** 0.1593017578125) * 18.8515625) + 0.8359375)  /   (((lmax ** 0.1593017578125) * 18.6875) + 1))**78.84375    


    #normalize the PQ values
    #e1=(x-0)/(lw-0) ==> e1= x / lw
    e1=core.std.Expr(clips=[c], expr="x  {lw} /".format(lw=lw))
    e1=core.std.Limiter(e1, 0,1)    
    
    
 
        
    #maxlum=(lmax-0)/(lw-0) ==> maxlum=lmax/lw
    maxlum=lmax/lw  
    
    #ks1=(1.5*lmax)- 0.5      
    ks1=(1.5*lmax)- 0.5
    
    #ks2=(1.5*maxlum)- 0.5
    ks2=(1.5*maxlum)- 0.5 
    
    #ks=(ks1+ks2)/2    
    ks=(ks1+ks2)/2
    
    #t=(x-ks)/(1-ks)
    t = core.std.Expr(clips=[e1], expr="x {ks} - 1 {ks} - / ".format(ks=ks))
    
    #p=(2t^3 - 3t^2 +1)*ks +( t^3-2t^2+t)*(1-ks)+(-2t^3+3t^2)* maxlum     
    p = core.std.Expr(clips=[t], expr="  2 x 3 pow *  3 x 2 pow   * - 1 + {ks} * 1 {ks} - x 3 pow  2 x 2 pow *    -   x  + * + -2 x 3 pow  *  3 x 2 pow  *  + {maxlum} * +".format(ks=ks,maxlum=maxlum))
    
    e2=core.std.Expr(clips=[e1,p], expr="x {ks} < x y ? ".format(ks=ks))

    #e3=e2+0*(1-e2)^4 ==> e3=e2
    e3=e2  
     
    #invert the normalization of the PQ values
    #e4=[e3*(lw-0)]+0  ==> e4=e3*lw
    e4=core.std.Expr(clips=[e3], expr="x  {lw} * ".format(lw=lw))
    c=e4
    
    
    c=core.resize.Bicubic(clip=c, format=vs.RGBS, transfer_in_s=transfer_in_s, transfer_s="linear",dither_type="none", nominal_luminance=target_nits)


   
    c=core.resize.Bicubic(clip=c, format=vs.RGBS, primaries_in_s=primaries, primaries_s="709",dither_type="none")
    c=core.resize.Bicubic(clip=c, format=vs.RGBS, transfer_in_s="linear", transfer_s="709",dither_type="none")
    c=core.std.Limiter(c, 0,1)


    c=core.resize.Bicubic(clip=c, format=vs.YUV422P16,matrix_s="709", filter_param_a=0, filter_param_b=0.75, range_in_s="full",range_s="limited", chromaloc_in_s="center", chromaloc_s="center",dither_type="none")  
      
    return c

    
c=bt2390test(c,target_nits=100,masterdisplay=None,transfer=None,matrix=None,primaries=None)






c.set_output()