ARRI LogC to LUTs corrected.

[OpenColorIO-Configs.git] / aces_1.0.0 / python / aces_ocio / create_arri_colorspaces.py

diff --git a/aces_1.0.0/python/aces_ocio/create_arri_colorspaces.py b/aces_1.0.0/python/aces_ocio/create_arri_colorspaces.py
index 76af824..e0d1a3f 100644 (file)
--- a/aces_1.0.0/python/aces_ocio/create_arri_colorspaces.py
+++ b/aces_1.0.0/python/aces_ocio/create_arri_colorspaces.py
@@ -5,10 +5,14 @@
 Implements support for *ARRI* colorspaces conversions and transfer functions.
 """
 
+from __future__ import division
+
 import array
 import math
 import os
 
+import PyOpenColorIO as ocio
+
 import aces_ocio.generate_lut as genlut
 from aces_ocio.utilities import ColorSpace, mat44_from_mat33, sanitize
 
@@ -49,7 +53,7 @@ def create_log_c(gamut,
 
     name = '%s (EI%s) - %s' % (transfer_function, exposure_index, gamut)
     if transfer_function == '':
-        name = 'Linear - %s' % gamut
+        name = 'Linear - ARRI %s' % gamut
     if gamut == '':
         name = '%s (EI%s)' % (transfer_function, exposure_index)
 
@@ -57,13 +61,18 @@ def create_log_c(gamut,
     cs.description = name
     cs.aliases = aliases
     cs.equality_group = ''
-    cs.family = 'ARRI'
+    cs.family = 'Input/ARRI'
     cs.is_data = False
 
+    # A linear space needs allocation variables
+    if transfer_function == '':
+        cs.allocation_type = ocio.Constants.ALLOCATION_LG2
+        cs.allocation_vars = [-8, 5, 0.00390625]
+
     # Globals.
     IDT_maker_version = '0.08'
 
-    nominal_EI = 400.0
+    nominal_EI = 400
     black_signal = 0.003907
     mid_gray_signal = 0.01
     encoding_gain = 0.256598
@@ -74,8 +83,8 @@ def create_log_c(gamut,
             0.89 - 1) / 3 + 1) * encoding_gain
 
     def log_c_inverse_parameters_for_EI(EI):
-        cut = 1.0 / 9.0
-        slope = 1.0 / (cut * math.log(10))
+        cut = 1 / 9
+        slope = 1 / (cut * math.log(10))
         offset = math.log10(cut) - slope * cut
         gain = EI / nominal_EI
         gray = mid_gray_signal / gain
@@ -83,10 +92,10 @@ def create_log_c(gamut,
         enc_gain = gain_for_EI(EI)
         enc_offset = encoding_offset
         for i in range(0, 3):
-            nz = ((95.0 / 1023.0 - enc_offset) / enc_gain - offset) / slope
+            nz = ((95 / 1023 - enc_offset) / enc_gain - offset) / slope
             enc_offset = encoding_offset - math.log10(1 + nz) * enc_gain
 
-        a = 1.0 / gray
+        a = 1 / gray
         b = nz - black_signal / gray
         e = slope * a * enc_gain
         f = enc_gain * (slope * b + offset) + enc_offset
@@ -107,14 +116,14 @@ def create_log_c(gamut,
                 'e': e,
                 'f': f}
 
-    def log_c_to_linear(code_value, exposure_index):
+    def normalized_log_c_to_linear(code_value, exposure_index):
         p = log_c_inverse_parameters_for_EI(exposure_index)
         breakpoint = p['e'] * p['cut'] + p['f']
         if code_value > breakpoint:
-            linear = ((pow(10, (code_value / 1023.0 - p['d']) / p['c']) -
+            linear = ((pow(10, (code_value - p['d']) / p['c']) -
                        p['b']) / p['a'])
         else:
-            linear = (code_value / 1023.0 - p['f']) / p['e']
+            linear = (code_value - p['f']) / p['e']
         return linear
 
     cs.to_reference_transforms = []
@@ -122,8 +131,8 @@ def create_log_c(gamut,
     if transfer_function == 'V3 LogC':
         data = array.array('f', '\0' * lut_resolution_1d * 4)
         for c in range(lut_resolution_1d):
-            data[c] = log_c_to_linear(1023.0 * c / (lut_resolution_1d - 1),
-                                      int(exposure_index))
+            data[c] = normalized_log_c_to_linear(c / (lut_resolution_1d - 1),
+                                                 int(exposure_index))
 
         lut = '%s_to_linear.spi1d' % (
             '%s_%s' % (transfer_function, exposure_index))
@@ -132,8 +141,8 @@ def create_log_c(gamut,
 
         genlut.write_SPI_1d(
             os.path.join(lut_directory, lut),
-            0.0,
-            1.0,
+            0,
+            1,
             data,
             lut_resolution_1d,
             1)
@@ -178,8 +187,8 @@ def create_colorspaces(lut_directory, lut_resolution_1d):
     transfer_function = 'V3 LogC'
     gamut = 'Wide Gamut'
 
-    # EIs = [160.0, 200.0, 250.0, 320.0, 400.0, 500.0, 640.0, 800.0,
-    # 1000.0, 1280.0, 1600.0, 2000.0, 2560.0, 3200.0]
+    # EIs = [160, 200, 250, 320, 400, 500, 640, 800,
+    # 1000, 1280, 1600, 2000, 2560, 3200]
     EIs = [160, 200, 250, 320, 400, 500, 640, 800,
            1000, 1280, 1600, 2000, 2560, 3200]
     default_EI = 800