feat(openexr): ACES Container hint for exr outputs

src/doc/builtinplugins.rst

@@ -1643,6 +1643,18 @@ control aspects of the writing itself:
    * - Output Configuration Attribute
      - Type
      - Meaning
+   * - ``oiio:ACESContainer``
+     - string
+     - One of `none` (default), `strict`, or `relaxed`.
+       If not `none`, the spec will be checked to see if it is compliant
+       with the ACES Container format defined in `ST 2065-4`_. If it is,
+       `chromaticities` will be set to the ACES AP0 ones, and the
+       `acesImageContainerFlag` attribute will be set to 1.
+       In `strict` mode, if the spec is non-compliant, the output will
+       throw an error and avoid writing the image.
+       While in `relaxed` mode, if the spec in non-compliant, only a
+       warning will be printed and the attributes mentioned above will
+       *not* be written to the spec.
    * - ``oiio:RawColor``
      - int
      - If nonzero, writing images with non-RGB color models (such as YCbCr)
@@ -1654,6 +1666,7 @@ control aspects of the writing itself:
      - Pointer to a ``Filesystem::IOProxy`` that will handle the I/O, for
        example by writing to a memory buffer.
 
+.. _ST 2065-4: https://pub.smpte.org/doc/st2065-4/20130510-pub/st2065-4-2013.pdf
 
 **Custom I/O Overrides**
 

src/openexr.imageio/exroutput.cpp

@@ -290,6 +290,71 @@ set_exr_threads()
 
 
 
+constexpr float ACES_AP0_chromaticities[8] = {
+    0.7347f,  0.2653f,  // red
+    0.0f,     1.0f,     // green
+    0.0001f,  -0.077f,  // blue
+    0.32168f, 0.33767f  // white
+};
+
+
+
+bool
+is_aces_container_compliant(const OIIO::ImageSpec& spec)
+{
+    // Check channels
+    std::vector<std::string> allowed_sets
+        = { "B,G,R",
+            "A,B,G,R"
+            "B,G,R,left.B,left.G,left.R",
+            "A,B,G,R,left.A,left.B,left.G,left.R" };
+    std::string channels;
+    for (int c = 0; c < spec.nchannels; ++c) {
+        if (c > 0)
+            channels += ",";
+        channels += spec.channelnames[c];
+    }
+    if (std::find(allowed_sets.begin(), allowed_sets.end(), channels)
+        == allowed_sets.end())
+        return false;
+
+    // Check data type
+    if (spec.format != OIIO::TypeDesc::HALF)
+        return false;
+
+    // Check compression
+    std::string compression = spec.get_string_attribute("compression", "zip");
+    if (compression != "none")
+        return false;
+
+    return true;
+}
+
+
+
+bool
+process_aces_container(OIIO::ImageSpec& spec, std::string mode)
+{
+    bool is_compliant = is_aces_container_compliant(spec);
+
+    if (!is_compliant) {
+        std::cerr << "WARNING: Image spec is not ACES Container compliant\n";
+
+        // early out and return true iff in "relaxed" mode
+        // to indicate that the output can continue without
+        // throwing an error
+        return mode == "relaxed";
+    }
+
+    spec.attribute("chromaticities", OIIO::TypeDesc(OIIO::TypeDesc::FLOAT, 8),
+                   ACES_AP0_chromaticities);
+    spec.attribute("acesImageContainerFlag", 1);
+
+    return true;
+}
+
+
+
 OpenEXROutput::OpenEXROutput()
 {
     pvt::set_exr_threads();
@@ -812,6 +877,20 @@ OpenEXROutput::spec_to_header(ImageSpec& spec, int subimage,
                                  Imf::LevelMode(m_levelmode),
                                  Imf::LevelRoundingMode(m_roundingmode)));
 
+    // Check ACES Container hint
+    std::string aces_mode = spec.get_string_attribute("oiio:ACESContainer",
+                                                      "none");
+    if (aces_mode == "strict" || aces_mode == "relaxed") {
+        bool should_panic = !process_aces_container(spec, aces_mode);
+
+        if (should_panic) {
+            const char* non_compliance_message
+                = "Cannot output non-compliant ACES Container in 'strict' mode.";
+            errorfmt(non_compliance_message);
+            return false;
+        }
+    }
+
     // Deal with all other params
     for (const auto& p : spec.extra_attribs)
         put_parameter(p.name().string(), p.type(), p.data(), header);

testsuite/openexr-suite/ref/out.txt

@@ -341,3 +341,35 @@ negoverscan.exr      :   64 x   64, 3 channel, half openexr
     screenWindowWidth: 1
     oiio:subimages: 1
     openexr:lineOrder: "increasingY"
+1
+WARNING: Image spec is not ACES Container compliant
+
+WARNING: Image spec is not ACES Container compliant
+
+WARNING: Image spec is not ACES Container compliant
+
+Reading strict-out.exr
+strict-out.exr       :    4 x    4, 3 channel, half openexr
+    SHA-1: C49A9785B2243F2F080DAAD1747F119ACCECCFA5
+    channel list: R, G, B
+    acesImageContainerFlag: 1
+    chromaticities: 0.7347, 0.2653, 0, 1, 0.0001, -0.077, 0.32168, 0.33767
+    compression: "none"
+    PixelAspectRatio: 1
+    screenWindowCenter: 0, 0
+    screenWindowWidth: 1
+    oiio:ColorSpace: "lin_ap0_scene"
+    oiio:subimages: 1
+    openexr:lineOrder: "increasingY"
+WARNING: Image spec is not ACES Container compliant
+oiiotool ERROR: -o : Cannot output non-compliant ACES Container in 'strict' mode.
+Full command line was:
+> oiiotool --create 4x4 3 -d half --compression none --ch R,G,B -sattrib oiio:ACESContainer strict -o strict-fail.exr
+WARNING: Image spec is not ACES Container compliant
+oiiotool ERROR: -o : Cannot output non-compliant ACES Container in 'strict' mode.
+Full command line was:
+> oiiotool --create 4x4 3 -d half --compression zip --ch B,G,R -sattrib oiio:ACESContainer strict -o strict-fail.exr
+WARNING: Image spec is not ACES Container compliant
+oiiotool ERROR: -o : Cannot output non-compliant ACES Container in 'strict' mode.
+Full command line was:
+> oiiotool --create 4x4 3 -d float --compression none --ch B,G,R -sattrib oiio:ACESContainer strict -o strict-fail.exr

testsuite/openexr-suite/run.py

@@ -50,3 +50,20 @@
 # Check writing overscan and negative range
 command += oiiotool("--create 64x64-16-16 3 -d half -o negoverscan.exr")
 command += info_command("negoverscan.exr", safematch=True)
+
+# Check ACES Container output for relaxed mode
+command += oiiotool("--create 4x4 3 -d half --compression none --ch B,G,R -sattrib oiio:ACESContainer relaxed -o relaxed-out.exr")
+command += oiiotool("relaxed-out.exr --echo {TOP[acesImageContainerFlag]}", failureok=True) # should give 1
+command += oiiotool("--create 4x4 3 -d half --compression none --ch R,G,B -sattrib oiio:ACESContainer relaxed -o fail.exr")
+command += oiiotool("fail.exr --echo {TOP[acesImageContainerFlag]}", failureok=True) # should be empty
+command += oiiotool("--create 4x4 3 -d half --compression zip --ch B,G,R -sattrib oiio:ACESContainer relaxed -o fail.exr")
+command += oiiotool("fail.exr --echo {TOP[acesImageContainerFlag]}", failureok=True) # should be empty
+command += oiiotool("--create 4x4 3 -d float --compression none --ch B,G,R -sattrib oiio:ACESContainer relaxed -o fail.exr")
+command += oiiotool("fail.exr --echo {TOP[acesImageContainerFlag]}", failureok=True) # should be empty
+
+# Check ACES Container output for strict mode
+command += oiiotool("--create 4x4 3 -d half --compression none --ch B,G,R -sattrib oiio:ACESContainer strict -o strict-out.exr")
+command += info_command("strict-out.exr", safematch=True)
+command += oiiotool("--create 4x4 3 -d half --compression none --ch R,G,B -sattrib oiio:ACESContainer strict -o strict-fail.exr", failureok=True)
+command += oiiotool("--create 4x4 3 -d half --compression zip --ch B,G,R -sattrib oiio:ACESContainer strict -o strict-fail.exr", failureok=True)
+command += oiiotool("--create 4x4 3 -d float --compression none --ch B,G,R -sattrib oiio:ACESContainer strict -o strict-fail.exr", failureok=True)