+++ /dev/null
-#!/usr/bin/env python
-# -*- coding: utf-8 -*-
-
-"""
-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
-
-__author__ = 'ACES Developers'
-__copyright__ = 'Copyright (C) 2014 - 2015 - ACES Developers'
-__license__ = ''
-__maintainer__ = 'ACES Developers'
-__email__ = 'aces@oscars.org'
-__status__ = 'Production'
-
-__all__ = ['create_log_c',
- 'create_colorspaces']
-
-
-def create_log_c(gamut,
- transfer_function,
- exposure_index,
- lut_directory,
- lut_resolution_1d,
- aliases):
- """
- Creates colorspace covering the conversion from LogC to ACES, with various transfer
- functions and encoding gamuts covered
-
- Parameters
- ----------
- gamut : str
- The name of the encoding gamut to use.
- transfer_function : str
- The name of the transfer function to use
- exposure_index : str
- The exposure index to use
- lut_directory : str or unicode
- The directory to use when generating LUTs
- lut_resolution_1d : int
- The resolution of generated 1D LUTs
- aliases : list of str
- Aliases for this colorspace
-
- Returns
- -------
- ColorSpace
- A ColorSpace container class referencing the LUTs, matrices and identifying
- information for the requested colorspace.
- """
-
- name = '%s (EI%s) - %s' % (transfer_function, exposure_index, gamut)
- if transfer_function == '':
- name = 'Linear - ARRI %s' % gamut
- if gamut == '':
- name = 'Curve - %s (EI%s)' % (transfer_function, exposure_index)
-
- cs = ColorSpace(name)
- cs.description = name
- cs.aliases = aliases
- cs.equality_group = ''
- cs.family = 'Input/ARRI'
- cs.is_data = False
-
- if gamut and transfer_function:
- cs.aces_transform_id = (
- 'IDT.ARRI.Alexa-v3-logC-EI%s.a1.v1' % exposure_index)
-
- # A linear space needs allocation variables.
- if transfer_function == '':
- cs.allocation_type = ocio.Constants.ALLOCATION_LG2
- cs.allocation_vars = [-8, 5, 0.00390625]
-
- IDT_maker_version = '0.08'
-
- nominal_EI = 400
- black_signal = 0.003907
- mid_gray_signal = 0.01
- encoding_gain = 0.256598
- encoding_offset = 0.391007
-
- def gain_for_EI(EI):
- return (math.log(EI / nominal_EI) / math.log(2) * (
- 0.89 - 1) / 3 + 1) * encoding_gain
-
- def log_c_inverse_parameters_for_EI(EI):
- cut = 1 / 9
- slope = 1 / (cut * math.log(10))
- offset = math.log10(cut) - slope * cut
- gain = EI / nominal_EI
- gray = mid_gray_signal / gain
- # The higher the EI, the lower the gamma.
- enc_gain = gain_for_EI(EI)
- enc_offset = encoding_offset
- for i in range(0, 3):
- nz = ((95 / 1023 - enc_offset) / enc_gain - offset) / slope
- enc_offset = encoding_offset - math.log10(1 + nz) * enc_gain
-
- a = 1 / gray
- b = nz - black_signal / gray
- e = slope * a * enc_gain
- f = enc_gain * (slope * b + offset) + enc_offset
-
- # Ensuring we can return relative exposure.
- s = 4 / (0.18 * EI)
- t = black_signal
- b += a * t
- a *= s
- f += e * t
- e *= s
-
- return {'a': a,
- 'b': b,
- 'cut': (cut - b) / a,
- 'c': enc_gain,
- 'd': enc_offset,
- 'e': e,
- 'f': f}
-
- 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 - p['d']) / p['c']) -
- p['b']) / p['a'])
- else:
- linear = (code_value - p['f']) / p['e']
- return linear
-
- cs.to_reference_transforms = []
-
- if transfer_function == 'V3 LogC':
- data = array.array('f', '\0' * lut_resolution_1d * 4)
- for c in range(lut_resolution_1d):
- 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))
-
- lut = sanitize(lut)
-
- genlut.write_SPI_1d(
- os.path.join(lut_directory, lut),
- 0,
- 1,
- data,
- lut_resolution_1d,
- 1)
-
- cs.to_reference_transforms.append({
- 'type': 'lutFile',
- 'path': lut,
- 'interpolation': 'linear',
- 'direction': 'forward'})
-
- if gamut == 'Wide Gamut':
- cs.to_reference_transforms.append({
- 'type': 'matrix',
- 'matrix': mat44_from_mat33([0.680206, 0.236137, 0.083658,
- 0.085415, 1.017471, -0.102886,
- 0.002057, -0.062563, 1.060506]),
- 'direction': 'forward'})
-
- cs.from_reference_transforms = []
- return cs
-
-
-def create_colorspaces(lut_directory, lut_resolution_1d):
- """
- Generates the colorspace conversions.
-
- Parameters
- ----------
- lut_directory : str or unicode
- The directory to use when generating LUTs
- lut_resolution_1d : int
- The resolution of generated 1D LUTs
-
- Returns
- -------
- list
- A list of colorspaces for ARRI cameras and encodings
- """
-
- colorspaces = []
-
- transfer_function = 'V3 LogC'
- gamut = 'Wide Gamut'
-
- # 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
-
- # Full Conversion
- for EI in EIs:
- log_c_EI_full = create_log_c(
- gamut,
- transfer_function,
- EI,
- lut_directory,
- lut_resolution_1d,
- ['%sei%s_%s' % ('logc3', str(EI), 'arriwide')])
- colorspaces.append(log_c_EI_full)
-
- # Linearization Only
- for EI in [800]:
- log_c_EI_linearization = create_log_c(
- '',
- transfer_function,
- EI,
- lut_directory,
- lut_resolution_1d,
- ['crv_%sei%s' % ('logc3', str(EI))])
- colorspaces.append(log_c_EI_linearization)
-
- # Primaries Only
- log_c_EI_primaries = create_log_c(
- gamut,
- '',
- default_EI,
- lut_directory,
- lut_resolution_1d,
- ['%s_%s' % ('lin', 'arriwide')])
- colorspaces.append(log_c_EI_primaries)
-
- return colorspaces
projects / OpenColorIO-Configs.git / blobdiff