2 # -*- coding: utf-8 -*-
7 import aces_ocio.generateLUT as genlut
8 from aces_ocio.util import ColorSpace, mat44FromMat33
20 name = "%s (EI%s) - %s" % (transferFunction, exposureIndex, gamut)
21 if transferFunction == "":
22 name = "Linear - %s" % gamut
24 name = "%s (EI%s)" % (transferFunction, exposureIndex)
33 IDT_maker_version = "0.08"
36 blackSignal = 0.003907
38 encodingGain = 0.256598
39 encodingOffset = 0.391007
42 return (math.log(EI / nominalEI) / math.log(2) * (
43 0.89 - 1) / 3 + 1) * encodingGain
45 def LogCInverseParametersForEI(EI):
47 slope = 1.0 / (cut * math.log(10))
48 offset = math.log10(cut) - slope * cut
50 gray = midGraySignal / gain
51 # The higher the EI, the lower the gamma
52 encGain = gainForEI(EI)
53 encOffset = encodingOffset
55 nz = ((95.0 / 1023.0 - encOffset) / encGain - offset) / slope
56 encOffset = encodingOffset - math.log10(1 + nz) * encGain
57 # Calculate some intermediate values
59 b = nz - blackSignal / gray
60 e = slope * a * encGain
61 f = encGain * (slope * b + offset) + encOffset
62 # Manipulations so we can return relative exposure
77 def logCtoLinear(codeValue, exposureIndex):
78 p = LogCInverseParametersForEI(exposureIndex)
79 breakpoint = p['e'] * p['cut'] + p['f']
80 if (codeValue > breakpoint):
81 linear = ((pow(10, (codeValue / 1023.0 - p['d']) / p['c']) -
84 linear = (codeValue / 1023.0 - p['f']) / p['e']
86 # print(codeValue, linear)
90 cs.toReferenceTransforms = []
92 if transferFunction == "V3 LogC":
93 data = array.array('f', "\0" * lutResolution1d * 4)
94 for c in range(lutResolution1d):
95 data[c] = logCtoLinear(1023.0 * c / (lutResolution1d - 1),
98 lut = "%s_to_linear.spi1d" % (
99 "%s_%s" % (transferFunction, exposureIndex))
101 # Remove spaces and parentheses
102 lut = lut.replace(' ', '_').replace(')', '_').replace('(', '_')
104 genlut.writeSPI1D(lutDir + "/" + lut,
111 # print("Writing %s" % lut)
112 cs.toReferenceTransforms.append({
115 'interpolation': 'linear',
116 'direction': 'forward'
119 if gamut == 'Wide Gamut':
120 cs.toReferenceTransforms.append({
122 'matrix': mat44FromMat33([0.680206, 0.236137, 0.083658,
123 0.085415, 1.017471, -0.102886,
124 0.002057, -0.062563, 1.060506]),
125 'direction': 'forward'
128 cs.fromReferenceTransforms = []
132 def createColorSpaces(lutDir, lutResolution1d):
135 transferFunction = "V3 LogC"
137 # EIs = [160.0, 200.0, 250.0, 320.0, 400.0, 500.0, 640.0, 800.0,
138 # 1000.0, 1280.0, 1600.0, 2000.0, 2560.0, 3200.0]
139 EIs = [160, 200, 250, 320, 400, 500, 640, 800,
140 1000, 1280, 1600, 2000, 2560, 3200]
145 LogCEIfull = createLogC(
146 gamut, transferFunction, EI, "LogC", lutDir, lutResolution1d)
147 colorspaces.append(LogCEIfull)
151 LogCEIlinearization = createLogC(
152 "", transferFunction, EI, "LogC", lutDir, lutResolution1d)
153 colorspaces.append(LogCEIlinearization)
156 LogCEIprimaries = createLogC(
157 gamut, "", defaultEI, "LogC", lutDir, lutResolution1d)
158 colorspaces.append(LogCEIprimaries)