def create_Dolby_PQ_scaled(aces_ctl_directory,
lut_directory,
lut_resolution_1d,
cleanup,
name='pq',
aliases=None,
min_value=0.0,
max_value=1.0,
input_scale=1.0,
middle_grey=0.18,
min_exposure=-6.0,
max_exposure=6.5):
if aliases is None:
aliases = []
cs = ColorSpace(name)
cs.description = 'The %s color space' % name
cs.aliases = aliases
cs.equality_group = name
cs.family = 'Utility'
cs.is_data = False
ctls = [os.path.join(
aces_ctl_directory,
'utilities',
'ACESlib.OCIOShaper_to_lin_param.a1.0.0.ctl')]
lut = '%s_to_linear.spi1d' % name
lut = sanitize(lut)
generate_1d_LUT_from_CTL(
os.path.join(lut_directory, lut),
ctls,
lut_resolution_1d,
'float',
input_scale,
1.0,
{'middleGrey': middle_grey,
'minExposure': min_exposure,
'maxExposure': max_exposure},
cleanup,
aces_ctl_directory,
min_value,
max_value)
cs.to_reference_transforms = []
cs.to_reference_transforms.append({
'type': 'lutFile',
'path': lut,
'interpolation': 'linear',
'direction': 'forward'})
cs.from_reference_transforms = []
return cs
def create_dolbypq_scaled(
aces_CTL_directory,
lut_directory,
lut_resolution_1d,
cleanup,
name="pq",
aliases=[],
min_value=0.0,
max_value=1.0,
input_scale=1.0,
middle_grey=0.18,
min_exposure=-6.0,
max_exposure=6.5,
):
cs = ColorSpace(name)
cs.description = "The %s color space" % name
cs.aliases = aliases
cs.equality_group = name
cs.family = "Utility"
cs.is_data = False
ctls = [os.path.join(aces_CTL_directory, "utilities", "ACESlib.DolbyPQ_to_lin_param.a1.0.0.ctl")]
lut = "%s_to_linear.spi1d" % name
lut = sanitize(lut)
generate_1d_LUT_from_CTL(
os.path.join(lut_directory, lut),
ctls,
lut_resolution_1d,
"float",
input_scale,
1.0,
{"middleGrey": middle_grey, "minExposure": min_exposure, "maxExposure": max_exposure},
cleanup,
aces_CTL_directory,
min_value,
max_value,
)
cs.to_reference_transforms = []
cs.to_reference_transforms.append(
{"type": "lutFile", "path": lut, "interpolation": "linear", "direction": "forward"}
)
cs.from_reference_transforms = []
return cs
def create_dolbypq(aces_CTL_directory,
lut_directory,
lut_resolution_1d,
cleanup,
name='pq',
aliases=[],
min_value=0.0,
max_value=1.0,
input_scale=1.0):
cs = ColorSpace(name)
cs.description = 'The %s color space' % name
cs.aliases = aliases
cs.equality_group = name
cs.family = 'Utility'
cs.is_data = False
ctls = [os.path.join(
aces_CTL_directory,
'utilities',
'ACESlib.OCIO_shaper_dolbypq_to_lin.a1.0.0.ctl')]
lut = '%s_to_linear.spi1d' % name
lut = sanitize(lut)
generate_1d_LUT_from_CTL(
os.path.join(lut_directory, lut),
ctls,
lut_resolution_1d,
'float',
input_scale,
1.0,
{},
cleanup,
aces_CTL_directory,
min_value,
max_value)
cs.to_reference_transforms = []
cs.to_reference_transforms.append({
'type': 'lutFile',
'path': lut,
'interpolation': 'linear',
'direction': 'forward'})
cs.from_reference_transforms = []
return cs
def create_ACES_RRT_plus_ODT(odt_name,
odt_values,
shaper_info,
aces_ctl_directory,
lut_directory,
lut_resolution_3d=64,
cleanup=True,
aliases=None):
"""
Object description.
Parameters
----------
parameter : type
Parameter description.
Returns
-------
type
Return value description.
"""
if aliases is None:
aliases = []
cs = ColorSpace('%s' % odt_name)
cs.description = '%s - %s Output Transform' % (
odt_values['transformUserNamePrefix'], odt_name)
cs.aliases = aliases
cs.equality_group = ''
cs.family = 'Output'
cs.is_data = False
cs.aces_transform_id = odt_values['transformID']
pprint.pprint(odt_values)
# Generating the *shaper* transform.
(shaper_name,
shaper_to_aces_ctl,
shaper_from_aces_ctl,
shaper_input_scale,
shaper_params) = shaper_info
if 'legalRange' in odt_values:
shaper_params['legalRange'] = odt_values['legalRange']
else:
shaper_params['legalRange'] = 0
shaper_lut = '%s_to_linear.spi1d' % shaper_name
shaper_lut = sanitize(shaper_lut)
shaper_ocio_transform = {
'type': 'lutFile',
'path': shaper_lut,
'interpolation': 'linear',
'direction': 'inverse'}
# Generating the *forward* transform.
cs.from_reference_transforms = []
if 'transformLUT' in odt_values:
transform_lut_file_name = os.path.basename(
odt_values['transformLUT'])
lut = os.path.join(lut_directory, transform_lut_file_name)
shutil.copy(odt_values['transformLUT'], lut)
cs.from_reference_transforms.append(shaper_ocio_transform)
cs.from_reference_transforms.append({
'type': 'lutFile',
'path': transform_lut_file_name,
'interpolation': 'tetrahedral',
'direction': 'forward'})
elif 'transformCTL' in odt_values:
ctls = [
shaper_to_aces_ctl % aces_ctl_directory,
os.path.join(aces_ctl_directory,
'rrt',
'RRT.a1.0.0.ctl'),
os.path.join(aces_ctl_directory,
'odt',
odt_values['transformCTL'])]
lut = '%s.RRT.a1.0.0.%s.spi3d' % (shaper_name, odt_name)
lut = sanitize(lut)
generate_3d_LUT_from_CTL(
os.path.join(lut_directory, lut),
ctls,
lut_resolution_3d,
'float',
1 / shaper_input_scale,
1,
shaper_params,
cleanup,
aces_ctl_directory)
cs.from_reference_transforms.append(shaper_ocio_transform)
cs.from_reference_transforms.append({
'type': 'lutFile',
'path': lut,
'interpolation': 'tetrahedral',
'direction': 'forward'})
# Generating the *inverse* transform.
cs.to_reference_transforms = []
if 'transformLUTInverse' in odt_values:
transform_lut_inverse_file_name = os.path.basename(
odt_values['transformLUTInverse'])
lut = os.path.join(lut_directory, transform_lut_inverse_file_name)
shutil.copy(odt_values['transformLUTInverse'], lut)
cs.to_reference_transforms.append({
'type': 'lutFile',
'path': transform_lut_inverse_file_name,
'interpolation': 'tetrahedral',
'direction': 'forward'})
shaper_inverse = shaper_ocio_transform.copy()
shaper_inverse['direction'] = 'forward'
cs.to_reference_transforms.append(shaper_inverse)
elif 'transformCTLInverse' in odt_values:
ctls = [os.path.join(aces_ctl_directory,
'odt',
odt_values['transformCTLInverse']),
os.path.join(aces_ctl_directory,
'rrt',
'InvRRT.a1.0.0.ctl'),
shaper_from_aces_ctl % aces_ctl_directory]
lut = 'InvRRT.a1.0.0.%s.%s.spi3d' % (odt_name, shaper_name)
lut = sanitize(lut)
generate_3d_LUT_from_CTL(
os.path.join(lut_directory, lut),
ctls,
lut_resolution_3d,
'half',
1,
shaper_input_scale,
shaper_params,
cleanup,
aces_ctl_directory)
cs.to_reference_transforms.append({
'type': 'lutFile',
'path': lut,
'interpolation': 'tetrahedral',
'direction': 'forward'})
shaper_inverse = shaper_ocio_transform.copy()
shaper_inverse['direction'] = 'forward'
cs.to_reference_transforms.append(shaper_inverse)
return cs
def create_ACES_LMT(lmt_name,
lmt_values,
shaper_info,
aces_ctl_directory,
lut_directory,
lut_resolution_3d=64,
cleanup=True,
aliases=None):
"""
Creates the *ACES LMT* colorspace.
Parameters
----------
parameter : type
Parameter description.
Returns
-------
Colorspace
*ACES LMT* colorspace.
"""
if aliases is None:
aliases = []
cs = ColorSpace('%s' % lmt_name)
cs.description = 'The ACES Look Transform: %s' % lmt_name
cs.aliases = aliases
cs.equality_group = ''
cs.family = 'Look'
cs.is_data = False
cs.allocation_type = ocio.Constants.ALLOCATION_LG2
cs.allocation_vars = [-8, 5, 0.00390625]
cs.aces_transform_id = lmt_values['transformID']
pprint.pprint(lmt_values)
# Generating the *shaper* transform.
(shaper_name,
shaper_to_aces_ctl,
shaper_from_aces_ctl,
shaper_input_scale,
shaper_params) = shaper_info
shaper_lut = '%s_to_linear.spi1d' % shaper_name
shaper_lut = sanitize(shaper_lut)
shaper_ocio_transform = {
'type': 'lutFile',
'path': shaper_lut,
'interpolation': 'linear',
'direction': 'inverse'}
# Generating the forward transform.
cs.from_reference_transforms = []
if 'transformCTL' in lmt_values:
ctls = [shaper_to_aces_ctl % aces_ctl_directory,
os.path.join(aces_ctl_directory,
lmt_values['transformCTL'])]
lut = '%s.%s.spi3d' % (shaper_name, lmt_name)
lut = sanitize(lut)
generate_3d_LUT_from_CTL(
os.path.join(lut_directory, lut),
ctls,
lut_resolution_3d,
'float',
1 / shaper_input_scale,
1,
shaper_params,
cleanup,
aces_ctl_directory)
cs.from_reference_transforms.append(shaper_ocio_transform)
cs.from_reference_transforms.append({
'type': 'lutFile',
'path': lut,
'interpolation': 'tetrahedral',
'direction': 'forward'})
# Generating the inverse transform.
cs.to_reference_transforms = []
if 'transformCTLInverse' in lmt_values:
ctls = [os.path.join(aces_ctl_directory,
lmt_values['transformCTLInverse']),
shaper_from_aces_ctl % aces_ctl_directory]
lut = 'Inverse.%s.%s.spi3d' % (lmt_name, shaper_name)
lut = sanitize(lut)
generate_3d_LUT_from_CTL(
os.path.join(lut_directory, lut),
ctls,
lut_resolution_3d,
'half',
1,
shaper_input_scale,
shaper_params,
cleanup,
aces_ctl_directory,
0)
cs.to_reference_transforms.append({
'type': 'lutFile',
'path': lut,
'interpolation': 'tetrahedral',
'direction': 'forward'})
shaper_inverse = shaper_ocio_transform.copy()
shaper_inverse['direction'] = 'forward'
cs.to_reference_transforms.append(shaper_inverse)
return cs
def create_ACESproxy(aces_ctl_directory,
lut_directory,
lut_resolution_1d,
cleanup,
name='ACESproxy'):
"""
Creates the *ACESproxy* colorspace.
Parameters
----------
parameter : type
Parameter description.
Returns
-------
Colorspace
*ACESproxy* colorspace.
"""
cs = ColorSpace(name)
cs.description = 'The %s color space' % name
cs.aliases = ['acesproxy', 'acesproxy_ap1']
cs.equality_group = ''
cs.family = 'ACES'
cs.is_data = False
cs.aces_transform_id = 'ACEScsc.ACESproxy10i_to_ACES.a1.0.0'
ctls = [os.path.join(aces_ctl_directory,
'ACESproxy',
'ACEScsc.ACESproxy10i_to_ACES.a1.0.0.ctl'),
# This transform gets back to the *AP1* primaries.
# Useful as the 1d LUT is only covering the transfer function.
# The primaries switch is covered by the matrix below:
os.path.join(aces_ctl_directory,
'ACEScg',
'ACEScsc.ACES_to_ACEScg.a1.0.0.ctl')]
lut = '%s_to_linear.spi1d' % name
lut = sanitize(lut)
generate_1d_LUT_from_CTL(
os.path.join(lut_directory, lut),
ctls,
lut_resolution_1d,
'float',
1,
1,
{},
cleanup,
aces_ctl_directory,
0,
1,
1)
cs.to_reference_transforms = []
cs.to_reference_transforms.append({
'type': 'lutFile',
'path': lut,
'interpolation': 'linear',
'direction': 'forward'})
# *AP1* primaries to *AP0* primaries
cs.to_reference_transforms.append({
'type': 'matrix',
'matrix': mat44_from_mat33(ACES_AP1_TO_AP0),
'direction': 'forward'})
cs.from_reference_transforms = []
return cs
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_protune(gamut, transfer_function, lut_directory, lut_resolution_1d,
aliases):
"""
Creates colorspace covering the conversion from ProTune 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
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.
"""
# The gamut should be marked as experimental until matrices are fully
# verified.
name = '%s - %s - Experimental' % (transfer_function, gamut)
if transfer_function == '':
name = 'Linear - %s - Experimental' % gamut
if gamut == '':
name = 'Curve - %s' % transfer_function
cs = ColorSpace(name)
cs.description = name
cs.aliases = aliases
cs.equality_group = ''
cs.family = 'Input/GoPro'
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]
def protune_to_linear(normalized_code_value):
c1 = 113.0
c2 = 1.0
c3 = 112.0
linear = ((pow(c1, normalized_code_value) - c2) / c3)
return linear
cs.to_reference_transforms = []
if transfer_function == 'Protune Flat':
data = array.array('f', '\0' * lut_resolution_1d * 4)
for c in range(lut_resolution_1d):
data[c] = protune_to_linear(float(c) / (lut_resolution_1d - 1))
lut = '%s_to_linear.spi1d' % transfer_function
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 == 'Protune Native':
cs.to_reference_transforms.append({
'type':
'matrix',
'matrix': [
0.533448429, 0.32413911, 0.142412421, 0, -0.050729924,
1.07572006, -0.024990416, 0, 0.071419661, -0.290521962,
1.219102381, 0, 0, 0, 0, 1
],
'direction':
'forward'
})
cs.from_reference_transforms = []
return cs
def create_log_c(gamut, transfer_function, exposure_index, lut_directory,
lut_resolution_1d, aliases):
"""
Creates a 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 - ALEXA %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 = '0.09'
nominal_exposure_index = 400
black_signal = 16 / 4095 # 0.003907
mid_gray_signal = 0.01
encoding_gain = 500 / 1023 * 0.525 # 0.256598
encoding_offset = 400 / 1023 # 0.391007
def gain_for_EI(ei):
return (math.log(ei / nominal_exposure_index) / math.log(2) *
(0.89 - 1) / 3 + 1) * encoding_gain
def hermite_weights(x, x1, x2):
d = x2 - x1
s = (x - x1) / d
s2 = 1 - s
return [(1 + 2 * s) * s2 * s2, (3 - 2 * s) * s * s, d * s * s2 * s2,
-d * s * s * s2]
def normalized_sensor_to_relative_exposure(ns, ei):
return (ns - black_signal) * (
0.18 / (mid_gray_signal * nominal_exposure_index / ei))
def normalized_log_c_to_linear(code_value, exposure_index):
cut = 1 / 9
slope = 1 / (cut * math.log(10))
offset = math.log10(cut) - slope * cut
gain = exposure_index / nominal_exposure_index
gray = mid_gray_signal / gain
# The higher the EI, the lower the gamma.
enc_gain = (math.log(gain) / math.log(2) *
(0.89 - 1) / 3 + 1) * encoding_gain
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
# see if we need to bring the hermite spline into play
xm = math.log10((1 - black_signal) / gray + nz) * enc_gain + enc_offset
if xm > 1.0:
if code_value > 0.8:
hw = hermite_weights(code_value, 0.8, 1)
d = 0.2 / (xm - 0.8)
v = [0.8, xm, 1.0, 1 / (d * d)]
# reconstruct code value from spline
code_value = 0
for i in range(0, 4):
code_value += (hw[i] * v[i])
code_value = (code_value - enc_offset) / enc_gain
# compute normalized sensor value
ns = pow(10, code_value) if (code_value - offset) / slope > cut else (
code_value - offset) / slope
ns = (ns - nz) * gray + black_signal
return normalized_sensor_to_relative_exposure(ns, exposure_index)
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_ACES_RRT_plus_ODT(
odt_name,
odt_values,
shaper_info,
aces_ctl_directory,
lut_directory,
lut_resolution_1d=1024,
lut_resolution_3d=64,
cleanup=True,
aliases=None,
):
"""
Object description.
Parameters
----------
parameter : type
Parameter description.
Returns
-------
type
Return value description.
"""
if aliases is None:
aliases = []
cs = ColorSpace("%s" % odt_name)
cs.description = "%s - %s Output Transform" % (odt_values["transformUserNamePrefix"], odt_name)
cs.aliases = aliases
cs.equality_group = ""
cs.family = "Output"
cs.is_data = False
cs.aces_transform_id = odt_values["transformID"]
pprint.pprint(odt_values)
# Generating the *shaper* transform.
(shaper_name, shaper_to_ACES_CTL, shaper_from_ACES_CTL, shaper_input_scale, shaper_params) = shaper_info
if "legalRange" in odt_values:
shaper_params["legalRange"] = odt_values["legalRange"]
else:
shaper_params["legalRange"] = 0
# Add the shaper transform
shaper_lut = "%s_to_linear.spi1d" % shaper_name
shaper_lut = sanitize(shaper_lut)
shaper_OCIO_transform = {"type": "lutFile", "path": shaper_lut, "interpolation": "linear", "direction": "inverse"}
# Generating the *forward* transform.
cs.from_reference_transforms = []
if "transformLUT" in odt_values:
transform_LUT_file_name = os.path.basename(odt_values["transformLUT"])
lut = os.path.join(lut_directory, transform_LUT_file_name)
shutil.copy(odt_values["transformLUT"], lut)
cs.from_reference_transforms.append(shaper_OCIO_transform)
cs.from_reference_transforms.append(
{"type": "lutFile", "path": transform_LUT_file_name, "interpolation": "tetrahedral", "direction": "forward"}
)
elif "transformCTL" in odt_values:
ctls = [
shaper_to_ACES_CTL % aces_ctl_directory,
os.path.join(aces_ctl_directory, "rrt", "RRT.a1.0.0.ctl"),
os.path.join(aces_ctl_directory, "odt", odt_values["transformCTL"]),
]
lut = "%s.RRT.a1.0.0.%s.spi3d" % (shaper_name, odt_name)
lut = sanitize(lut)
generate_3d_LUT_from_CTL(
os.path.join(lut_directory, lut),
# shaperLUT,
ctls,
lut_resolution_3d,
"float",
1 / shaper_input_scale,
1,
shaper_params,
cleanup,
aces_ctl_directory,
)
cs.from_reference_transforms.append(shaper_OCIO_transform)
cs.from_reference_transforms.append(
{"type": "lutFile", "path": lut, "interpolation": "tetrahedral", "direction": "forward"}
)
# Generating the *inverse* transform.
cs.to_reference_transforms = []
if "transformLUTInverse" in odt_values:
transform_LUT_inverse_file_name = os.path.basename(odt_values["transformLUTInverse"])
lut = os.path.join(lut_directory, transform_LUT_inverse_file_name)
shutil.copy(odt_values["transformLUTInverse"], lut)
cs.to_reference_transforms.append(
{
"type": "lutFile",
"path": transform_LUT_inverse_file_name,
"interpolation": "tetrahedral",
"direction": "forward",
}
)
shaper_inverse = shaper_OCIO_transform.copy()
shaper_inverse["direction"] = "forward"
cs.to_reference_transforms.append(shaper_inverse)
elif "transformCTLInverse" in odt_values:
ctls = [
os.path.join(aces_ctl_directory, "odt", odt_values["transformCTLInverse"]),
os.path.join(aces_ctl_directory, "rrt", "InvRRT.a1.0.0.ctl"),
shaper_from_ACES_CTL % aces_ctl_directory,
]
lut = "InvRRT.a1.0.0.%s.%s.spi3d" % (odt_name, shaper_name)
lut = sanitize(lut)
generate_3d_LUT_from_CTL(
os.path.join(lut_directory, lut),
# None,
ctls,
lut_resolution_3d,
"half",
1,
shaper_input_scale,
shaper_params,
cleanup,
aces_ctl_directory,
)
cs.to_reference_transforms.append(
{"type": "lutFile", "path": lut, "interpolation": "tetrahedral", "direction": "forward"}
)
shaper_inverse = shaper_OCIO_transform.copy()
shaper_inverse["direction"] = "forward"
cs.to_reference_transforms.append(shaper_inverse)
return cs
def create_ACES_LMT(
lmt_name,
lmt_values,
shaper_info,
aces_ctl_directory,
lut_directory,
lut_resolution_1d=1024,
lut_resolution_3d=64,
cleanup=True,
aliases=None,
):
"""
Creates the *ACES LMT* colorspace.
Parameters
----------
parameter : type
Parameter description.
Returns
-------
Colorspace
*ACES LMT* colorspace.
"""
if aliases is None:
aliases = []
cs = ColorSpace("%s" % lmt_name)
cs.description = "The ACES Look Transform: %s" % lmt_name
cs.aliases = aliases
cs.equality_group = ""
cs.family = "Look"
cs.is_data = False
cs.allocation_type = ocio.Constants.ALLOCATION_LG2
cs.allocation_vars = [-8, 5, 0.00390625]
cs.aces_transform_id = lmt_values["transformID"]
pprint.pprint(lmt_values)
# Generating the *shaper* transform.
(shaper_name, shaper_to_ACES_CTL, shaper_from_ACES_CTL, shaper_input_scale, shaper_params) = shaper_info
# Add the shaper transform
shaper_lut = "%s_to_linear.spi1d" % shaper_name
shaper_lut = sanitize(shaper_lut)
shaper_OCIO_transform = {"type": "lutFile", "path": shaper_lut, "interpolation": "linear", "direction": "inverse"}
# Generating the forward transform.
cs.from_reference_transforms = []
if "transformCTL" in lmt_values:
ctls = [shaper_to_ACES_CTL % aces_ctl_directory, os.path.join(aces_ctl_directory, lmt_values["transformCTL"])]
lut = "%s.%s.spi3d" % (shaper_name, lmt_name)
lut = sanitize(lut)
generate_3d_LUT_from_CTL(
os.path.join(lut_directory, lut),
ctls,
lut_resolution_3d,
"float",
1 / shaper_input_scale,
1,
shaper_params,
cleanup,
aces_ctl_directory,
)
cs.from_reference_transforms.append(shaper_OCIO_transform)
cs.from_reference_transforms.append(
{"type": "lutFile", "path": lut, "interpolation": "tetrahedral", "direction": "forward"}
)
# Generating the inverse transform.
cs.to_reference_transforms = []
if "transformCTLInverse" in lmt_values:
ctls = [
os.path.join(aces_ctl_directory, lmt_values["transformCTLInverse"]),
shaper_from_ACES_CTL % aces_ctl_directory,
]
lut = "Inverse.%s.%s.spi3d" % (odt_name, shaper_name)
lut = sanitize(lut)
generate_3d_LUT_from_CTL(
os.path.join(lut_directory, lut),
ctls,
lut_resolution_3d,
"half",
1,
shaper_input_scale,
shaper_params,
cleanup,
aces_ctl_directory,
0,
1,
1,
)
cs.to_reference_transforms.append(
{"type": "lutFile", "path": lut, "interpolation": "tetrahedral", "direction": "forward"}
)
shaper_inverse = shaper_OCIO_transform.copy()
shaper_inverse["direction"] = "forward"
cs.to_reference_transforms.append(shaper_inverse)
return cs
def create_generic_log(
aces_ctl_directory,
lut_directory,
lut_resolution_1d,
cleanup,
name="log",
aliases=[],
min_value=0,
max_value=1,
input_scale=1,
middle_grey=0.18,
min_exposure=-6,
max_exposure=6.5,
):
"""
Creates the *Generic Log* colorspace.
Parameters
----------
parameter : type
Parameter description.
Returns
-------
Colorspace
*Generic Log* colorspace.
"""
cs = ColorSpace(name)
cs.description = "The %s color space" % name
cs.aliases = aliases
cs.equality_group = name
cs.family = "Utility"
cs.is_data = False
ctls = [os.path.join(aces_ctl_directory, "utilities", "ACESlib.Log2_to_Lin_param.a1.0.0.ctl")]
lut = "%s_to_linear.spi1d" % name
lut = sanitize(lut)
generate_1d_LUT_from_CTL(
os.path.join(lut_directory, lut),
ctls,
lut_resolution_1d,
"float",
input_scale,
1,
{"middleGrey": middle_grey, "minExposure": min_exposure, "maxExposure": max_exposure},
cleanup,
aces_ctl_directory,
min_value,
max_value,
1,
)
cs.to_reference_transforms = []
cs.to_reference_transforms.append(
{"type": "lutFile", "path": lut, "interpolation": "linear", "direction": "forward"}
)
cs.from_reference_transforms = []
return cs
def create_ACESproxy(aces_ctl_directory, lut_directory, lut_resolution_1d, cleanup, name="ACESproxy"):
"""
Creates the *ACESproxy* colorspace.
Parameters
----------
parameter : type
Parameter description.
Returns
-------
Colorspace
*ACESproxy* colorspace.
"""
cs = ColorSpace(name)
cs.description = "The %s color space" % name
cs.aliases = ["acesproxy", "acesproxy_ap1"]
cs.equality_group = ""
cs.family = "ACES"
cs.is_data = False
cs.aces_transform_id = "ACEScsc.ACESproxy10i_to_ACES.a1.0.0"
ctls = [
os.path.join(aces_ctl_directory, "ACESproxy", "ACEScsc.ACESproxy10i_to_ACES.a1.0.0.ctl"),
# This transform gets back to the *AP1* primaries.
# Useful as the 1d LUT is only covering the transfer function.
# The primaries switch is covered by the matrix below:
os.path.join(aces_ctl_directory, "ACEScg", "ACEScsc.ACES_to_ACEScg.a1.0.0.ctl"),
]
lut = "%s_to_linear.spi1d" % name
lut = sanitize(lut)
generate_1d_LUT_from_CTL(
os.path.join(lut_directory, lut),
ctls,
lut_resolution_1d,
"float",
1,
1,
{},
cleanup,
aces_ctl_directory,
0,
1,
1,
)
cs.to_reference_transforms = []
cs.to_reference_transforms.append(
{"type": "lutFile", "path": lut, "interpolation": "linear", "direction": "forward"}
)
# *AP1* primaries to *AP0* primaries.
cs.to_reference_transforms.append(
{"type": "matrix", "matrix": mat44_from_mat33(ACES_AP1_TO_AP0), "direction": "forward"}
)
cs.from_reference_transforms = []
return cs
def create_log_c(gamut, transfer_function, exposure_index, lut_directory, lut_resolution_1d, aliases):
"""
Object description.
LogC to ACES.
Parameters
----------
parameter : type
Parameter description.
Returns
-------
type
Return value description.
"""
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_protune(gamut,
transfer_function,
lut_directory,
lut_resolution_1d,
aliases):
"""
Creates colorspace covering the conversion from ProTune 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
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.
"""
# The gamut should be marked as experimental until matrices are fully
# verified.
name = '%s - %s - Experimental' % (transfer_function, gamut)
if transfer_function == '':
name = 'Linear - %s - Experimental' % gamut
if gamut == '':
name = 'Curve - %s' % transfer_function
cs = ColorSpace(name)
cs.description = name
cs.aliases = aliases
cs.equality_group = ''
cs.family = 'Input/GoPro'
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]
def protune_to_linear(normalized_code_value):
c1 = 113.0
c2 = 1.0
c3 = 112.0
linear = ((pow(c1, normalized_code_value) - c2) / c3)
return linear
cs.to_reference_transforms = []
if transfer_function == 'Protune Flat':
data = array.array('f', '\0' * lut_resolution_1d * 4)
for c in range(lut_resolution_1d):
data[c] = protune_to_linear(float(c) / (lut_resolution_1d - 1))
lut = '%s_to_linear.spi1d' % transfer_function
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 == 'Protune Native':
cs.to_reference_transforms.append({
'type': 'matrix',
'matrix': [0.533448429, 0.32413911, 0.142412421, 0,
-0.050729924, 1.07572006, -0.024990416, 0,
0.071419661, -0.290521962, 1.219102381, 0,
0, 0, 0, 1],
'direction': 'forward'})
cs.from_reference_transforms = []
return cs
def create_ACEScc(aces_ctl_directory,
lut_directory,
lut_resolution_1d,
cleanup,
name='ACEScc',
min_value=0,
max_value=1,
input_scale=1):
"""
Creates the *ACEScc* colorspace.
Parameters
----------
parameter : type
Parameter description.
Returns
-------
Colorspace
*ACEScc* colorspace.
"""
cs = ColorSpace(name)
cs.description = 'The %s color space' % name
cs.aliases = ["acescc_ap1"]
cs.equality_group = ''
cs.family = 'ACES'
cs.is_data = False
cs.allocation_type = ocio.Constants.ALLOCATION_UNIFORM
cs.allocation_vars = [min_value, max_value]
ctls = [os.path.join(aces_ctl_directory,
'ACEScc',
'ACEScsc.ACEScc_to_ACES.a1.0.0.ctl')]
lut = '%s_to_linear.spi1d' % name
lut = sanitize(lut)
generate_1d_LUT_from_CTL(
os.path.join(lut_directory, lut),
ctls,
lut_resolution_1d,
'float',
input_scale,
1,
{'transferFunctionOnly':1},
cleanup,
aces_ctl_directory,
min_value,
max_value,
1)
cs.to_reference_transforms = []
cs.to_reference_transforms.append({
'type': 'lutFile',
'path': lut,
'interpolation': 'linear',
'direction': 'forward'})
# *AP1* primaries to *AP0* primaries.
cs.to_reference_transforms.append({
'type': 'matrix',
'matrix': mat44_from_mat33(ACES_AP1_TO_AP0),
'direction': 'forward'})
cs.from_reference_transforms = []
return cs
def create_log_c(gamut,
transfer_function,
exposure_index,
name,
lut_directory,
lut_resolution_1d,
aliases):
"""
Object description.
LogC to ACES.
Parameters
----------
parameter : type
Parameter description.
Returns
-------
type
Return value description.
"""
name = '%s (EI%s) - %s' % (transfer_function, exposure_index, gamut)
if transfer_function == '':
name = 'Linear - ARRI %s' % gamut
if gamut == '':
name = '%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
# 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
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 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 - p['d']) / p['c']) -
p['b']) / p['a'])
else:
linear = (code_value / 1023 - 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] = log_c_to_linear(1023 * 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_generic_log(aces_ctl_directory,
lut_directory,
lut_resolution_1d,
cleanup,
name='log',
aliases=[],
min_value=0,
max_value=1,
input_scale=1,
middle_grey=0.18,
min_exposure=-6,
max_exposure=6.5):
"""
Creates the *Generic Log* colorspace.
Parameters
----------
parameter : type
Parameter description.
Returns
-------
Colorspace
*Generic Log* colorspace.
"""
cs = ColorSpace(name)
cs.description = 'The %s color space' % name
cs.aliases = aliases
cs.equality_group = name
cs.family = 'Utility'
cs.is_data = False
ctls = [os.path.join(
aces_ctl_directory,
'utilities',
'ACESlib.OCIO_shaper_log2_to_lin_param.a1.0.0.ctl')]
lut = '%s_to_linear.spi1d' % name
lut = sanitize(lut)
generate_1d_LUT_from_CTL(
os.path.join(lut_directory, lut),
ctls,
lut_resolution_1d,
'float',
input_scale,
1,
{'middleGrey': middle_grey,
'minExposure': min_exposure,
'maxExposure': max_exposure},
cleanup,
aces_ctl_directory,
min_value,
max_value,
1)
cs.to_reference_transforms = []
cs.to_reference_transforms.append({
'type': 'lutFile',
'path': lut,
'interpolation': 'linear',
'direction': 'forward'})
cs.from_reference_transforms = []
return cs
def create_protune(gamut,
transfer_function,
lut_directory,
lut_resolution_1d,
aliases):
"""
Object description.
Protune to ACES.
Parameters
----------
parameter : type
Parameter description.
Returns
-------
type
Return value description.
"""
# The gamut should be marked as experimental until matrices are fully
# verified.
name = '%s - %s - Experimental' % (transfer_function, gamut)
if transfer_function == '':
name = 'Linear - %s - Experimental' % gamut
if gamut == '':
name = 'Curve - %s' % transfer_function
cs = ColorSpace(name)
cs.description = name
cs.aliases = aliases
cs.equality_group = ''
cs.family = 'Input/GoPro'
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]
def protune_to_linear(normalized_code_value):
c1 = 113.0
c2 = 1.0
c3 = 112.0
linear = ((pow(c1, normalized_code_value) - c2) / c3)
return linear
cs.to_reference_transforms = []
if transfer_function == 'Protune Flat':
data = array.array('f', '\0' * lut_resolution_1d * 4)
for c in range(lut_resolution_1d):
data[c] = protune_to_linear(float(c) / (lut_resolution_1d - 1))
lut = '%s_to_linear.spi1d' % transfer_function
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 == 'Protune Native':
cs.to_reference_transforms.append({
'type': 'matrix',
'matrix': [0.533448429, 0.32413911, 0.142412421, 0,
-0.050729924, 1.07572006, -0.024990416, 0,
0.071419661, -0.290521962, 1.219102381, 0,
0, 0, 0, 1],
'direction': 'forward'})
cs.from_reference_transforms = []
return cs
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