AcademySoftwareFoundation · lgritz · May 10, 2026
diff --git a/src/libOpenImageIO/color_ocio.cpp b/src/libOpenImageIO/color_ocio.cpp
@@ -201,8 +201,8 @@ struct CSInfo {
 // Hidden implementation of ColorConfig
 class ColorConfig::Impl {
 public:
-    OCIO::ConstConfigRcPtr config_;
-    OCIO::ConstConfigRcPtr builtinconfig_;
+    OCIO::ConfigRcPtr config_;
+    OCIO::ConfigRcPtr builtinconfig_;
 
 private:
     std::vector<CSInfo> colorspaces;
@@ -815,6 +815,49 @@ ColorConfig::~ColorConfig() {}
 
 
 
+// OIIO doctoring of OCIO configs for different default file rules. Currently,
+// we only do this for built-in configs.
+static void
+fix_config_file_rules(OCIO::ConfigRcPtr& config)
+{
+    OIIO_CONTRACT_ASSERT(config);
+    DBG("Fixing up rules:\n");
+#if 1
+    // Just start with a clean slate
+    auto rules = OCIO::FileRules::Create();
+#else
+    // Alternate universe: Start with the existing rules
+    auto rules = config->getFileRules()->createEditableCopy();
+#endif
+    for (size_t i = 0, e = rules->getNumEntries(); i != e; ++i) {
+        DBG("  rule {}/{}: pat='{}' ext='{}' -> \"{}\"\n", i, rules->getName(i),
+            rules->getRegex(i), rules->getExtension(i),
+            rules->getColorSpace(i));
+        if (Strutil::iequals(rules->getExtension(i), "exr")) {
+            // Change the rule for exr extension, if it exists, to "unknown".
+            // Make no assumptions. OCIO's built-in configs think it should be
+            // ACES2065-1, which is almost never right.
+            rules->setColorSpace(i, "unknown");
+            DBG("    changed cs to \"{}\"\n", rules->getColorSpace(i));
+        } else if (!strcmp(rules->getName(i), "Default")) {
+            // Default rule or one that matches everything -- for OIIO, we
+            // just want to change this to unknown. We made decisions about
+            // default per-file-format color space decisions in the individual
+            // readers. We don't even consider file extension to be reliable
+            // evidence of the file type.
+            rules->setColorSpace(i, "unknown");
+            DBG("    changed cs to \"{}\"\n", rules->getColorSpace(i));
+        }
+    }
+
+    // But make the path search rule (look for the right-most color space name
+    // embedded in the path) have precedence over file naming rules.
+    rules->insertPathSearchRule(0);
+    config->setFileRules(rules);
+}
+
+
+
 bool
 ColorConfig::Impl::init(string_view filename)
 {
@@ -825,7 +868,10 @@ ColorConfig::Impl::init(string_view filename)
     OCIO::SetLoggingLevel(OCIO::LOGGING_LEVEL_NONE);
 
     try {
-        builtinconfig_ = OCIO::Config::CreateFromFile("ocio://default");
+        auto cfg = OCIO::Config::CreateFromFile("ocio://default");
+        OIIO_CONTRACT_ASSERT(cfg);
+        builtinconfig_ = cfg->createEditableCopy();
+        fix_config_file_rules(builtinconfig_);
     } catch (OCIO::Exception& e) {
         error("Error making OCIO built-in config: {}", e.what());
     }
@@ -841,10 +887,13 @@ ColorConfig::Impl::init(string_view filename)
     } else {
         // Either filename passed, or taken from $OCIO, and it seems to exist
         try {
-            config_ = OCIO::Config::CreateFromFile(
-                std::string(filename).c_str());
             configname(filename);
-            m_config_is_built_in = Strutil::istarts_with(filename, "ocio://");
+            auto cfg = OCIO::Config::CreateFromFile(
+                std::string(filename).c_str());
+            if (cfg)
+                config_ = cfg->createEditableCopy();
+            if (config_ && Strutil::istarts_with(filename, "ocio://"))
+                fix_config_file_rules(config_);
         } catch (OCIO::Exception& e) {
             error("Error reading OCIO config \"{}\": {}", filename, e.what());
         } catch (...) {
@@ -2344,27 +2393,41 @@ ImageBufAlgo::colorconvert(ImageBuf& dst, const ImageBuf& src, string_view from,
         from = src.spec().get_string_attribute("oiio:Colorspace",
                                                "scene_linear");
     }
-    if (from.empty() || to.empty()) {
-        dst.errorfmt("Unknown color space name");
+    if (from.empty() || from == "unknown" || to.empty() || to == "unknown") {
+        dst.errorfmt("Unknown color space name (from=\"{}\", to=\"{}\")", from,
+                     to);
         return false;
     }
-    ColorProcessorHandle processor;
-    {
-        if (!colorconfig)
-            colorconfig = &ColorConfig::default_colorconfig();
-        processor
-            = colorconfig->createColorProcessor(colorconfig->resolve(from),
-                                                colorconfig->resolve(to),
-                                                context_key, context_value);
-        if (!processor) {
-            if (colorconfig->has_error())
-                dst.errorfmt("{}", colorconfig->geterror());
-            else
-                dst.errorfmt(
-                    "Could not construct the color transform {} -> {} (unknown error)",
-                    from, to);
-            return false;
-        }
+
+    if (!colorconfig)
+        colorconfig = &ColorConfig::default_colorconfig();
+
+    if (colorconfig->isData(from) || colorconfig->equivalent(from, "raw")) {
+        // If the input color space is not color managed, the transformation
+        // is meaningless, just set 'to' to the same space so that the whole
+        // thing is a no-op, including continuing to think it's in the raw
+        // space.
+        to = from;
+    } else if (colorconfig->isData(to) || colorconfig->equivalent(to, "raw")) {
+        // If the output color space is not color managed, the transformation
+        // is meaningless, just make it look like it's already in the 'from'
+        // space. Note that this DOES change the apparent color space label
+        // to the requested raw output space.
+        from = to;
+    }
+
+    ColorProcessorHandle processor
+        = colorconfig->createColorProcessor(colorconfig->resolve(from),
+                                            colorconfig->resolve(to),
+                                            context_key, context_value);
+    if (!processor) {
+        if (colorconfig->has_error())
+            dst.errorfmt("{}", colorconfig->geterror());
+        else
+            dst.errorfmt(
+                "Could not construct the color transform {} -> {} (unknown error)",
+                from, to);
+        return false;
     }
 
     logtime.stop(-1);  // transition to other colorconvert

diff --git a/src/oiiotool/oiiotool.cpp b/src/oiiotool/oiiotool.cpp
@@ -5566,6 +5566,8 @@ input_file(Oiiotool& ot, cspan<const char*> argv)
             // Try to deduce the color space it's in
             std::string colorspace(
                 ot.colorconfig().getColorSpaceFromFilepath(filename, "", true));
+            if (colorspace == "unknown")
+                colorspace.clear();
             if (colorspace.size() && ot.debug)
                 OIIO::print("  From {}, we deduce color space \"{}\"\n",
                             filename, colorspace);

diff --git a/testsuite/oiiotool-color/ref/out-ocio2.3.txt b/testsuite/oiiotool-color/ref/out-ocio2.3.txt
@@ -0,0 +1,65 @@
+oiiotool ERROR: --colorconfig : Requested non-existent OCIO config "missing.ocio"
+Full command line was:
+> oiiotool --nostderr --colorconfig missing.ocio -echo "Nonexistent config"
+nope: 0.5,0.5,0.5 half
+raw: 0.5,0.5,0.5 half
+acescg: 0.5,0.5,0.5 half
+srgb_tx: 0.5,0.5,0.5 half
+nope: 0.5,0.5,0.5 half
+raw: 0.5,0.5,0.5 half
+acescg: 0.5,0.5,0.5 half
+srgb_tx: 0.5,0.5,0.5 half
+Comparing "colormap-inferno.tif" and "ref/colormap-inferno.tif"
+PASS
+Comparing "colormap-custom.tif" and "ref/colormap-custom.tif"
+PASS
+Comparing "unpremult.exr" and "ref/unpremult.exr"
+PASS
+Comparing "premult.exr" and "ref/premult.exr"
+PASS
+Comparing "contrast-stretch.tif" and "ref/contrast-stretch.tif"
+PASS
+Comparing "contrast-shrink.tif" and "ref/contrast-shrink.tif"
+PASS
+Comparing "contrast-inverse.tif" and "ref/contrast-inverse.tif"
+PASS
+Comparing "contrast-threshold.tif" and "ref/contrast-threshold.tif"
+PASS
+Comparing "contrast-sigmoid5.tif" and "ref/contrast-sigmoid5.tif"
+PASS
+Comparing "display-sRGB.tif" and "ref/display-sRGB.tif"
+PASS
+Comparing "rgbfromtga.png" and "ref/rgbfromtga.png"
+PASS
+Comparing "greyalpha_sRGB.tif" and "ref/greyalpha_sRGB.tif"
+PASS
+Comparing "greyalpha_sRGB_un.tif" and "ref/greyalpha_sRGB_un-ocio22.tif"
+PASS
+Comparing "grey_sRGB.tif" and "ref/grey_sRGB.tif"
+PASS
+Comparing "grey_sRGB_un.tif" and "ref/grey_sRGB_un.tif"
+PASS
+Comparing "tahoe-ccmatrix.tif" and "ref/tahoe-ccmatrix.tif"
+PASS
+Comparing "tahoe-sat0.tif" and "ref/tahoe-sat0.tif"
+PASS
+Comparing "tahoe-sat2.tif" and "ref/tahoe-sat2.tif"
+PASS
+Comparing "cmap-magma.tif" and "ref/cmap-magma.tif"
+PASS
+Comparing "cmap-inferno.tif" and "ref/cmap-inferno.tif"
+PASS
+Comparing "cmap-plasma.tif" and "ref/cmap-plasma.tif"
+PASS
+Comparing "cmap-viridis.tif" and "ref/cmap-viridis.tif"
+PASS
+Comparing "cmap-turbo.tif" and "ref/cmap-turbo.tif"
+PASS
+Comparing "cmap-blue-red.tif" and "ref/cmap-blue-red.tif"
+PASS
+Comparing "cmap-spectrum.tif" and "ref/cmap-spectrum.tif"
+PASS
+Comparing "cmap-heat.tif" and "ref/cmap-heat.tif"
+PASS
+Comparing "look-default.tif" and "ref/look-default.tif"
+PASS
diff --git a/testsuite/oiiotool-color/ref/out.txt b/testsuite/oiiotool-color/ref/out.txt
@@ -1,6 +1,14 @@
 oiiotool ERROR: --colorconfig : Requested non-existent OCIO config "missing.ocio"
 Full command line was:
 > oiiotool --nostderr --colorconfig missing.ocio -echo "Nonexistent config"
+nope: 0.5,0.5,0.5 half
+raw: 0.5,0.5,0.5 half
+acescg: 0.5,0.5,0.5 half
+srgb_tx: 0.213989,0.213989,0.213989 half
+nope: 0.5,0.5,0.5 half
+raw: 0.5,0.5,0.5 half
+acescg: 0.5,0.5,0.5 half
+srgb_tx: 0.735352,0.735352,0.735352 half
 Comparing "colormap-inferno.tif" and "ref/colormap-inferno.tif"
 PASS
 Comparing "colormap-custom.tif" and "ref/colormap-custom.tif"

diff --git a/testsuite/oiiotool-color/run.py b/testsuite/oiiotool-color/run.py
@@ -7,6 +7,9 @@
 
 import os
 
+redirect = " >> out.txt 2>&1 "
+
+
 # print("ociover =", ociover)
 
 # Make test pattern with increasing intensity left to right, decreasing
@@ -97,6 +100,34 @@
 # test various behaviors and misbehaviors related to OCIO configs.
 command += oiiotool ("--nostderr --colorconfig missing.ocio -echo \"Nonexistent config\"", failureok=True)
 
+# Test what happens with autocc and input files with color space names in
+# their filenames, for both color-managed and non-color-managed spaces.
+#
+# Input: We transform an exr with each name to acescg, with autocc.
+# - "nope" is an unknown color space, and should warn.
+# - "raw" means known to be not color managed, and should warn.
+# - "acescg" is known and should end up with output (as acescg) that is
+#   unchanged, so the value should still be 0.5.
+# - "srgb_tx" is known but should make a real transformation, giving a pixel
+#   value that is not 0.5.
+for c in ("nope", "raw", "acescg", "srgb_tx") :
+    command += oiiotool (f"--pattern constant:color=.5 1x1 3 -d half -o in_{c}.exr")
+    command += oiiotool (f"--autocc in_{c}.exr -o out_acescg.exr")
+    command += oiiotool (f"out_acescg.exr -echo \"{c}: {{TOP.AVGCOLOR}} {{TOP.nativeformat}}\"")
+# Output: We transform an acescg image to outputs with each name, with autocc.
+# - "nope" is an unknown color space, and should warn. Or should it?
+# - "raw" should retain the 0.5 value with no warning, since you're asking to
+#   output a non-color-manaaged image.
+# - "acescg" is known and should end up with output (as acescg) that is
+#   unchanged, so the value should still be 0.5.
+# - "srgb_tx" is known but should make a real transformation, giving a pixel
+#   value that is not 0.5.
+for c in ("nope", "raw", "acescg", "srgb_tx") :
+    command += oiiotool (f"--pattern constant:color=.5 1x1 3 -d half -iscolorspace acescg "
+                         + f"-autocc -o out_{c}.exr")
+    command += oiiotool (f"out_{c}.exr -echo \"{c}: {{TOP.AVGCOLOR}} {{TOP.nativeformat}}\"")
+
+
 
 # To add more tests, just append more lines like the above and also add
 # the new 'feature.tif' (or whatever you call it) to the outputs list,

diff --git a/testsuite/python-colorconfig/ref/out-ocio230.txt b/testsuite/python-colorconfig/ref/out-ocio230.txt
@@ -0,0 +1,59 @@
+getNumColorSpaces = 15
+getColorSpaceNames = ['ACES2065-1', 'ACEScc', 'ACEScct', 'ACEScg', 'Linear P3-D65', 'Linear Rec.2020', 'Linear Rec.709 (sRGB)', 'Gamma 1.8 Rec.709 - Texture', 'Gamma 2.2 AP1 - Texture', 'Gamma 2.2 Rec.709 - Texture', 'Gamma 2.4 Rec.709 - Texture', 'sRGB Encoded AP1 - Texture', 'sRGB Encoded P3-D65 - Texture', 'sRGB - Texture', 'Raw']
+Index of 'lin_srgb' = 6
+Index of 'unknown' = -1
+Name of color space 2 = ACEScct
+getNumLooks = 1
+getLookNames = ['ACES 1.3 Reference Gamut Compression']
+getNumDisplays = 6
+getDisplayNames = ['sRGB - Display', 'Display P3 - Display', 'Rec.1886 Rec.709 - Display', 'Rec.2100-PQ - Display', 'ST2084-P3-D65 - Display', 'P3-D65 - Display']
+getDefaultDisplayName = sRGB - Display
+getNumViews = 3
+getViewNames = ['ACES 1.0 - SDR Video', 'Un-tone-mapped', 'Raw']
+getDefaultViewName = ACES 1.0 - SDR Video
+getNumRoles = 9
+getRoles = ['aces_interchange', 'cie_xyz_d65_interchange', 'color_picking', 'color_timing', 'compositing_log', 'data', 'matte_paint', 'scene_linear', 'texture_paint']
+aliases of 'scene_linear' are ['ACES - ACEScg', 'lin_ap1']
+resolve('foo'): foo
+resolve('linear'): Linear Rec.709 (sRGB)
+resolve('scene_linear'): ACEScg
+resolve('lin_srgb'): Linear Rec.709 (sRGB)
+resolve('srgb'): sRGB - Texture
+resolve('ACEScg'): ACEScg
+equivalent('lin_srgb', 'srgb'): False
+equivalent('scene_linear', 'srgb'): False
+equivalent('linear', 'lin_srgb'): False
+equivalent('scene_linear', 'lin_srgb'): False
+equivalent('ACEScg', 'scene_linear'): True
+equivalent('lnf', 'scene_linear'): False
+get_color_interop_id('ACEScg') =  lin_ap1_scene
+get_color_interop_id('lin_srgb') =  lin_rec709_scene
+get_color_interop_id([1, 13, 1, 1]) =  srgb_rec709_scene
+get_cicp('pq_rec2020_display') =  [9, 16, 9, 1]
+get_cicp('unknown_interop_id') =  None
+isColorSpaceLinear('scene_linear') =  True
+isColorSpaceLinear('srgb') =  False
+isData('scene_linear') =  False
+isData('Raw') =  True
+equivalent('ACEScg', 'Raw'): False
+getColorSpaceFromFilepath('in_acescg.exr') = ACEScg
+getColorSpaceFromFilepath('in_srgb_tx.exr') = sRGB - Texture
+getColorSpaceFromFilepath('in_raw.exr') = Raw
+getColorSpaceFromFilepath('none.exr') = unknown
+getColorSpaceFromFilepath('noclue.exr') = unknown
+
+Loaded test OCIO config: oiio_test_v0.9.2.ocio
+Parsed color space for filepath 'foo_lin_ap1.exr': ACEScg
+Default color space: lin_rec709
+Default display: sRGB (~2.22) - Display
+Default view for sRGB (~2.22) - Display (from lin_rec709): ACES 1.0 - SDR Video
+Default view for sRGB (~2.22) - Display (from 'srgb_tx'): Colorimetry
+Color space name from DisplayView transform referencing Shared View: sRGB (~2.22) - Display
+Test buffer -- initial values:                      [[[0.1 0.5 0.9]]]                 (ACEScg)
+ociodisplay #1 (apply default display/view):        [[[-2.123   0.671   0.8037]]]     (sRGB (~2.22) - Display)
+ociodisplay #2 (apply default display/view again):  [[[-2.783   0.766   0.9873]]]     (sRGB (~2.22) - Display)
+ociodisplay #3 (inverse look):                      [[[-18.22    0.876   2.121]]]     (sRGB (~2.22) - Display)
+ociodisplay #4 (forwards look):                     [[[-21330.       29.03    100.4 ]]]     (sRGB (~2.22) - Display)
+ociodisplay #5 (inverse look + forwards look):      [[[93.44 93.44 93.44]]]     (sRGB (~2.22) - Display)
+
+Done.