By the way, it should be mentioned that in some cases I've gotten better results with g-force's version 1.0 of the script than with the 1.1.

The difference is that 1.0 tried to also balance black and white levels to the reference clip used, and in 1.1 they are locked.

G, I hope you're ok with me re-posting 1.0 here:

Function RGBMatch(clip gref, clip bref)

{# Make RGB avg of second clip match first clip - v1.0 - by G-force

global gref = gref

global bref = bref

scriptclip(bref,"""

gref=gref.ConvertToRGB()

bref=bref.ConvertToRGB()

grefr = gref.ShowRed().ConvertToYV12()

grefg = gref.ShowGreen().ConvertToYV12()

grefb = gref.ShowBlue().ConvertToYV12()

brefr = bref.ShowRed().ConvertToYV12()

brefg = bref.ShowGreen().ConvertToYV12()

brefb = bref.ShowBlue().ConvertToYV12()

y1r = AverageLuma(grefr)

y1g = AverageLuma(grefg)

y1b = AverageLuma(grefb)

y2r = 0#Yplanemin(grefr)

y2g = 0#Yplanemin(grefg)

y2b = 0#Yplanemin(grefb)

y3r = 255#Yplanemax(grefr)

y3g = 255#Yplanemax(grefg)

y3b = 255#Yplanemax(grefb)

x1r = AverageLuma(brefr)

x1g = AverageLuma(brefg)

x1b = AverageLuma(brefb)

x2r = 0#Yplanemin(brefr)

x2g = 0#Yplanemin(brefg)

x2b = 0#Yplanemin(brefb)

x3r = 255#Yplanemax(brefr)

x3g = 255#Yplanemax(brefg)

x3b = 255#Yplanemax(brefb)

#compute coefficients for y=ax^2+bx+c using min, avg, max

ar = x1r==x2r? 0: x1r==x3r? 0: x2r==x3r? 0:

\ (y3r-y1r+(x1r-x3r)*(y1r-y2r)/(x1r-x2r))/((x1r-x3r)*(x2r-x3r))

br = x1r==x2r? 0:

\ ((y2r-y1r)/(x2r-x1r))-ar*(x1r+x2r)

cr = y1r-ar*x1r*x1r-br*x1r

ag = x1g==x2g? 0: x1g==x3g? 0: x2g==x3g? 0:

\ (y3g-y1g+(x1g-x3g)*(y1g-y2g)/(x1g-x2g))/((x1g-x3g)*(x2g-x3g))

bg = x1g==x2g? 0:

\ ((y2g-y1g)/(x2g-x1g))-ag*(x1g+x2g)

cg = y1g-ag*x1g*x1g-bg*x1g

ab = x1b==x2b? 0: x1b==x3b? 0: x2b==x3b? 0:

\ (y3b-y1b+(x1b-x3b)*(y1b-y2b)/(x1b-x2b))/((x1b-x3b)*(x2b-x3b))

bb = x1b==x2b? 0:

\ ((y2b-y1b)/(x2b-x1b))-ab*(x1b+x2b)

cb = y1b-ab*x1b*x1b-bb*x1b

brefr=brefr.MT_lut("x x * "+string(ar)+" * x "+string(br)+" * + "+string(cr)+" +").ConvertToRGB()

brefg=brefg.MT_lut("x x * "+string(ag)+" * x "+string(bg)+" * + "+string(cg)+" +").ConvertToRGB()

brefb=brefb.MT_lut("x x * "+string(ab)+" * x "+string(bb)+" * + "+string(cb)+" +").ConvertToRGB()

MergeRGB(brefr,brefg,brefb)

ConvertToYV12()

""")

Return(last)}