Implement support for "ARRI Wide Gamut 4" and "ARRI LogC4"

Closes #992.
colour-science · Nov 7, 2022 · d0152dc · d0152dc
1 parent a593876
commit d0152dc
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Showing 10 changed files with 411 additions and 2 deletions.
diff --git a/README.rst b/README.rst
@@ -1011,6 +1011,7 @@ RGB Colourspaces
      'ACEScg',
      'ACESproxy',
      'ARRI Wide Gamut 3',
+     'ARRI Wide Gamut 4',
      'Adobe RGB (1998)',
      'Adobe Wide Gamut RGB',
      'Apple RGB',
@@ -1127,6 +1128,7 @@ Log Encoding / Decoding
      'ACEScct',
      'ACESproxy',
      'ARRI LogC3',
+     'ARRI LogC4',
      'Canon Log',
      'Canon Log 2',
      'Canon Log 3',
@@ -1162,6 +1164,7 @@ CCTFs Encoding / Decoding
      'ACEScct',
      'ACESproxy',
      'ARRI LogC3',
+     'ARRI LogC4',
      'ARIB STD-B67',
      'Canon Log',
      'Canon Log 2',

diff --git a/colour/models/__init__.py b/colour/models/__init__.py
@@ -128,6 +128,8 @@
     oetf_inverse_ARIBSTDB67,
     log_encoding_ARRILogC3,
     log_decoding_ARRILogC3,
+    log_encoding_ARRILogC4,
+    log_decoding_ARRILogC4,
     oetf_BlackmagicFilmGeneration5,
     oetf_inverse_BlackmagicFilmGeneration5,
     log_encoding_CanonLog,
@@ -271,6 +273,7 @@
     RGB_COLOURSPACE_ADOBE_RGB1998,
     RGB_COLOURSPACE_ADOBE_WIDE_GAMUT_RGB,
     RGB_COLOURSPACE_ARRI_WIDE_GAMUT_3,
+    RGB_COLOURSPACE_ARRI_WIDE_GAMUT_4,
     RGB_COLOURSPACE_APPLE_RGB,
     RGB_COLOURSPACE_BEST_RGB,
     RGB_COLOURSPACE_BETA_RGB,
@@ -526,6 +529,8 @@
     "oetf_inverse_ARIBSTDB67",
     "log_encoding_ARRILogC3",
     "log_decoding_ARRILogC3",
+    "log_encoding_ARRILogC4",
+    "log_decoding_ARRILogC4",
     "oetf_BlackmagicFilmGeneration5",
     "oetf_inverse_BlackmagicFilmGeneration5",
     "log_encoding_CanonLog",
@@ -669,6 +674,7 @@
     "RGB_COLOURSPACE_ADOBE_RGB1998",
     "RGB_COLOURSPACE_ADOBE_WIDE_GAMUT_RGB",
     "RGB_COLOURSPACE_ARRI_WIDE_GAMUT_3",
+    "RGB_COLOURSPACE_ARRI_WIDE_GAMUT_4",
     "RGB_COLOURSPACE_APPLE_RGB",
     "RGB_COLOURSPACE_BEST_RGB",
     "RGB_COLOURSPACE_BETA_RGB",

diff --git a/colour/models/rgb/__init__.py b/colour/models/rgb/__init__.py
@@ -23,6 +23,8 @@
     oetf_inverse_ARIBSTDB67,
     log_encoding_ARRILogC3,
     log_decoding_ARRILogC3,
+    log_encoding_ARRILogC4,
+    log_decoding_ARRILogC4,
     oetf_BlackmagicFilmGeneration5,
     oetf_inverse_BlackmagicFilmGeneration5,
     log_encoding_CanonLog,
@@ -166,6 +168,7 @@
     RGB_COLOURSPACE_ADOBE_RGB1998,
     RGB_COLOURSPACE_ADOBE_WIDE_GAMUT_RGB,
     RGB_COLOURSPACE_ARRI_WIDE_GAMUT_3,
+    RGB_COLOURSPACE_ARRI_WIDE_GAMUT_4,
     RGB_COLOURSPACE_APPLE_RGB,
     RGB_COLOURSPACE_BEST_RGB,
     RGB_COLOURSPACE_BETA_RGB,
@@ -288,6 +291,8 @@
     "oetf_inverse_ARIBSTDB67",
     "log_encoding_ARRILogC3",
     "log_decoding_ARRILogC3",
+    "log_encoding_ARRILogC4",
+    "log_decoding_ARRILogC4",
     "oetf_BlackmagicFilmGeneration5",
     "oetf_inverse_BlackmagicFilmGeneration5",
     "log_encoding_CanonLog",
@@ -431,6 +436,7 @@
     "RGB_COLOURSPACE_ADOBE_RGB1998",
     "RGB_COLOURSPACE_ADOBE_WIDE_GAMUT_RGB",
     "RGB_COLOURSPACE_ARRI_WIDE_GAMUT_3",
+    "RGB_COLOURSPACE_ARRI_WIDE_GAMUT_4",
     "RGB_COLOURSPACE_APPLE_RGB",
     "RGB_COLOURSPACE_BEST_RGB",
     "RGB_COLOURSPACE_BETA_RGB",

diff --git a/colour/models/rgb/datasets/__init__.py b/colour/models/rgb/datasets/__init__.py
@@ -11,7 +11,10 @@
 from .adobe_rgb_1998 import RGB_COLOURSPACE_ADOBE_RGB1998
 from .adobe_wide_gamut_rgb import RGB_COLOURSPACE_ADOBE_WIDE_GAMUT_RGB
 from .apple_rgb import RGB_COLOURSPACE_APPLE_RGB
-from .arri import RGB_COLOURSPACE_ARRI_WIDE_GAMUT_3
+from .arri import (
+    RGB_COLOURSPACE_ARRI_WIDE_GAMUT_3,
+    RGB_COLOURSPACE_ARRI_WIDE_GAMUT_4,
+)
 from .best_rgb import RGB_COLOURSPACE_BEST_RGB
 from .beta_rgb import RGB_COLOURSPACE_BETA_RGB
 from .blackmagic_design import RGB_COLOURSPACE_BLACKMAGIC_WIDE_GAMUT
@@ -113,6 +116,7 @@
     "RGB_COLOURSPACE_ADOBE_RGB1998",
     "RGB_COLOURSPACE_ADOBE_WIDE_GAMUT_RGB",
     "RGB_COLOURSPACE_ARRI_WIDE_GAMUT_3",
+    "RGB_COLOURSPACE_ARRI_WIDE_GAMUT_4",
     "RGB_COLOURSPACE_APPLE_RGB",
     "RGB_COLOURSPACE_BEST_RGB",
     "RGB_COLOURSPACE_BETA_RGB",

diff --git a/colour/models/rgb/datasets/arri.py b/colour/models/rgb/datasets/arri.py
@@ -5,11 +5,16 @@
 Defines the *ARRI* colourspaces:
 
 -   :attr:`colour.models.RGB_COLOURSPACE_ARRI_WIDE_GAMUT_3`.
+-   :attr:`colour.models.RGB_COLOURSPACE_ARRI_WIDE_GAMUT_4`.
 
 References
 ----------
 -   :cite:`ARRI2012a` : ARRI. (2012). ALEXA - Log C Curve - Usage in VFX.
     https://drive.google.com/open?id=1t73fAG_QpV7hJxoQPYZDWvOojYkYDgvn
+-   :cite:`Cooper2022` : Cooper, S., & Brendel, H. (2022). ARRI LogC4
+    Logarithmic Color Space SPECIFICATION. Retrieved October 24, 2022, from
+    https://www.arri.com/resource/blob/278790/bea879ac0d041a925bed27a096ab3ec2/\
+2022-05-arri-logc4-specification-data.pdf
 """
 
 from __future__ import annotations
@@ -22,6 +27,8 @@
     RGB_Colourspace,
     log_encoding_ARRILogC3,
     log_decoding_ARRILogC3,
+    log_encoding_ARRILogC4,
+    log_decoding_ARRILogC4,
 )
 
 __author__ = "Colour Developers"
@@ -38,6 +45,12 @@
     "MATRIX_ARRI_WIDE_GAMUT_3_TO_XYZ",
     "MATRIX_XYZ_TO_ARRI_WIDE_GAMUT_3",
     "RGB_COLOURSPACE_ARRI_WIDE_GAMUT_3",
+    "PRIMARIES_ARRI_WIDE_GAMUT_4",
+    "WHITEPOINT_NAME_ARRI_WIDE_GAMUT_4",
+    "CCS_WHITEPOINT_ARRI_WIDE_GAMUT_4",
+    "MATRIX_ARRI_WIDE_GAMUT_4_TO_XYZ",
+    "MATRIX_XYZ_TO_ARRI_WIDE_GAMUT_4",
+    "RGB_COLOURSPACE_ARRI_WIDE_GAMUT_4",
 ]
 
 PRIMARIES_ARRI_WIDE_GAMUT_3: NDArray = np.array(
@@ -92,3 +105,52 @@
 ----------
 :cite:`ARRI2012a`
 """
+
+PRIMARIES_ARRI_WIDE_GAMUT_4: NDArray = np.array(
+    [
+        [0.7347, 0.2653],
+        [0.1424, 0.8576],
+        [0.0991, -0.0308],
+    ]
+)
+"""*ARRI Wide Gamut 4* colourspace primaries."""
+
+WHITEPOINT_NAME_ARRI_WIDE_GAMUT_4: str = "D65"
+"""*ARRI Wide Gamut 4* colourspace whitepoint name."""
+
+CCS_WHITEPOINT_ARRI_WIDE_GAMUT_4: NDArray = CCS_ILLUMINANTS[
+    "CIE 1931 2 Degree Standard Observer"
+][WHITEPOINT_NAME_ARRI_WIDE_GAMUT_4]
+"""*ARRI Wide Gamut 4* colourspace whitepoint chromaticity coordinates."""
+
+MATRIX_ARRI_WIDE_GAMUT_4_TO_XYZ: NDArray = np.array(
+    [
+        [0.7048583204, 0.1297602952, 0.1158373115],
+        [0.2545241764, 0.7814777327, -0.0360019091],
+        [0.0000000000, 0.0000000000, 1.0890577508],
+    ]
+)
+"""*ARRI Wide Gamut 4* colourspace to *CIE XYZ* tristimulus values matrix."""
+
+MATRIX_XYZ_TO_ARRI_WIDE_GAMUT_4: NDArray = np.linalg.inv(
+    MATRIX_ARRI_WIDE_GAMUT_4_TO_XYZ
+)
+"""*CIE XYZ* tristimulus values to *ARRI Wide Gamut 4* colourspace matrix."""
+
+RGB_COLOURSPACE_ARRI_WIDE_GAMUT_4: RGB_Colourspace = RGB_Colourspace(
+    "ARRI Wide Gamut 4",
+    PRIMARIES_ARRI_WIDE_GAMUT_4,
+    CCS_WHITEPOINT_ARRI_WIDE_GAMUT_4,
+    WHITEPOINT_NAME_ARRI_WIDE_GAMUT_4,
+    MATRIX_ARRI_WIDE_GAMUT_4_TO_XYZ,
+    MATRIX_XYZ_TO_ARRI_WIDE_GAMUT_4,
+    log_encoding_ARRILogC4,
+    log_decoding_ARRILogC4,
+)
+RGB_COLOURSPACE_ARRI_WIDE_GAMUT_4.__doc__ = """
+*ARRI Wide Gamut 4* colourspace.
+
+References
+----------
+:cite:`Cooper2022`
+"""
diff --git a/colour/models/rgb/transfer_functions/__init__.py b/colour/models/rgb/transfer_functions/__init__.py
@@ -27,7 +27,12 @@
     log_decoding_ACEScct,
 )
 from .arib_std_b67 import oetf_ARIBSTDB67, oetf_inverse_ARIBSTDB67
-from .arri import log_encoding_ARRILogC3, log_decoding_ARRILogC3
+from .arri import (
+    log_encoding_ARRILogC3,
+    log_decoding_ARRILogC3,
+    log_encoding_ARRILogC4,
+    log_decoding_ARRILogC4,
+)
 from .blackmagic_design import (
     oetf_BlackmagicFilmGeneration5,
     oetf_inverse_BlackmagicFilmGeneration5,
@@ -160,6 +165,8 @@
 __all__ += [
     "log_encoding_ARRILogC3",
     "log_decoding_ARRILogC3",
+    "log_encoding_ARRILogC4",
+    "log_decoding_ARRILogC4",
 ]
 __all__ += [
     "oetf_BlackmagicFilmGeneration5",
@@ -344,6 +351,7 @@
         "ACEScct": log_encoding_ACEScct,
         "ACESproxy": log_encoding_ACESproxy,
         "ARRI LogC3": log_encoding_ARRILogC3,
+        "ARRI LogC4": log_encoding_ARRILogC4,
         "Canon Log 2": log_encoding_CanonLog2,
         "Canon Log 3": log_encoding_CanonLog3,
         "Canon Log": log_encoding_CanonLog,
@@ -383,6 +391,7 @@ def log_encoding(
             "ACEScct",
             "ACESproxy",
             "ARRI LogC3",
+            "ARRI LogC4",
             "Canon Log 2",
             "Canon Log 3",
             "Canon Log",
@@ -430,6 +439,7 @@ def log_encoding(
         :func:`colour.models.log_encoding_ACEScct`,
         :func:`colour.models.log_encoding_ACESproxy`,
         :func:`colour.models.log_encoding_ARRILogC3`,
+        :func:`colour.models.log_encoding_ARRILogC4`,
         :func:`colour.models.log_encoding_CanonLog2`,
         :func:`colour.models.log_encoding_CanonLog3`,
         :func:`colour.models.log_encoding_CanonLog`,
@@ -491,6 +501,7 @@ def log_encoding(
         "ACEScct": log_decoding_ACEScct,
         "ACESproxy": log_decoding_ACESproxy,
         "ARRI LogC3": log_decoding_ARRILogC3,
+        "ARRI LogC4": log_decoding_ARRILogC4,
         "Canon Log 2": log_decoding_CanonLog2,
         "Canon Log 3": log_decoding_CanonLog3,
         "Canon Log": log_decoding_CanonLog,
@@ -530,6 +541,7 @@ def log_decoding(
             "ACEScct",
             "ACESproxy",
             "ARRI LogC3",
+            "ARRI LogC4",
             "Canon Log 2",
             "Canon Log 3",
             "Canon Log",
@@ -577,6 +589,7 @@ def log_decoding(
         :func:`colour.models.log_decoding_ACEScct`,
         :func:`colour.models.log_decoding_ACESproxy`,
         :func:`colour.models.log_decoding_ARRILogC3`,
+        :func:`colour.models.log_decoding_ARRILogC4`,
         :func:`colour.models.log_decoding_CanonLog2`,
         :func:`colour.models.log_decoding_CanonLog3`,
         :func:`colour.models.log_decoding_CanonLog`,
@@ -1044,6 +1057,7 @@ def cctf_encoding(
             "ACEScct",
             "ACESproxy",
             "ARRI LogC3",
+            "ARRI LogC4",
             "ARIB STD-B67",
             "Blackmagic Film Generation 5",
             "Canon Log 2",
@@ -1199,6 +1213,7 @@ def cctf_decoding(
             "ACEScct",
             "ACESproxy",
             "ARRI LogC3",
+            "ARRI LogC4",
             "ARIB STD-B67",
             "Blackmagic Film Generation 5",
             "Canon Log 2",