TRY: only set color space of unmarked exrs if it appears to be rgb

Signed-off-by: Larry Gritz <lg@larrygritz.com>

src/openexr.imageio/exr_pvt.h

@@ -44,20 +44,17 @@ static bool exrdebug = Strutil::stoi(Sysutil::getenv("OIIO_DEBUG_OPENEXR"))
 #endif
 
 
+namespace pvt {
+
 // Split a full channel name into layer and suffix.
-inline void
-split_name(string_view fullname, string_view& layer, string_view& suffix)
-{
-    size_t dot = fullname.find_last_of('.');
-    if (dot == string_view::npos) {
-        suffix = fullname;
-        layer  = string_view();
-    } else {
-        layer  = string_view(fullname.data(), dot + 1);
-        suffix = string_view(fullname.data() + dot + 1,
-                             fullname.size() - dot - 1);
-    }
-}
+void
+split_name(string_view fullname, string_view& layer, string_view& suffix);
+
+// Do the channels appear to be R, G, B (or known common aliases)?
+bool
+channels_are_rgb(const ImageSpec& spec);
+
+}  // namespace pvt
 
 
 

src/openexr.imageio/exrinput.cpp

@@ -148,6 +148,40 @@ namespace pvt {
 void
 set_exr_threads();
 
+
+// Split a full channel name into layer and suffix.
+void
+split_name(string_view fullname, string_view& layer, string_view& suffix)
+{
+    size_t dot = fullname.find_last_of('.');
+    if (dot == string_view::npos) {
+        suffix = fullname;
+        layer  = string_view();
+    } else {
+        layer  = string_view(fullname.data(), dot + 1);
+        suffix = string_view(fullname.data() + dot + 1,
+                             fullname.size() - dot - 1);
+    }
+}
+
+
+inline bool
+str_equal_either(string_view str, string_view a, string_view b)
+{
+    return Strutil::iequals(str, a) || Strutil::iequals(str, b);
+}
+
+
+// Do the channels appear to be R, G, B (or known common aliases)?
+bool
+channels_are_rgb(const ImageSpec& spec)
+{
+    return spec.nchannels >= 3
+           && str_equal_either(spec.channel_name(0), "R", "Red")
+           && str_equal_either(spec.channel_name(1), "G", "Green")
+           && str_equal_either(spec.channel_name(2), "B", "Blue");
+}
+
 }  // namespace pvt
 
 
@@ -357,8 +391,13 @@ OpenEXRInput::PartInfo::parse_header(OpenEXRInput* in,
 
     spec.deep = Strutil::istarts_with(header->type(), "deep");
 
-    // Unless otherwise specified, exr files are assumed to be linear Rec709.
-    spec.set_colorspace("lin_rec709");
+    // Unless otherwise specified, exr files are assumed to be linear Rec709
+    // if the channels appear to be R, G, B.  I know this suspect, but I'm
+    // betting that this heuristic will guess the right thing that users want
+    // more often than if we pretending we have no idea what the color space
+    // is.
+    if (pvt::channels_are_rgb(spec))
+        spec.set_colorspace("lin_rec709");
 
     if (levelmode != Imf::ONE_LEVEL)
         spec.attribute("openexr:roundingmode", roundingmode);
@@ -666,7 +705,7 @@ struct ChanNameHolder {
         , xSampling(exrchan.xSampling)
         , ySampling(exrchan.ySampling)
     {
-        split_name(fullname, layer, suffix);
+        pvt::split_name(fullname, layer, suffix);
     }
 
     // Compute canoninical channel list sort priority

src/openexr.imageio/exrinput_c.cpp

@@ -528,8 +528,13 @@ OpenEXRCoreInput::PartInfo::parse_header(OpenEXRCoreInput* in,
     spec.deep = (storage == EXR_STORAGE_DEEP_TILED
                  || storage == EXR_STORAGE_DEEP_SCANLINE);
 
-    // Unless otherwise specified, exr files are assumed to be linear Rec709.
-    spec.set_colorspace("lin_rec709");
+    // Unless otherwise specified, exr files are assumed to be linear Rec709
+    // if the channels appear to be R, G, B.  I know this suspect, but I'm
+    // betting that this heuristic will guess the right thing that users want
+    // more often than if we pretending we have no idea what the color space
+    // is.
+    if (pvt::channels_are_rgb(spec))
+        spec.set_colorspace("lin_rec709");
 
     if (levelmode != EXR_TILE_ONE_LEVEL)
         spec.attribute("openexr:roundingmode", (int)roundingmode);
@@ -806,7 +811,7 @@ struct CChanNameHolder {
         , xSampling(exrchan.x_sampling)
         , ySampling(exrchan.y_sampling)
     {
-        split_name(fullname, layer, suffix);
+        pvt::split_name(fullname, layer, suffix);
     }
 
     // Compute canoninical channel list sort priority

testsuite/iinfo/ref/out-fmt6.txt

@@ -212,7 +212,6 @@ src/tinydeep.exr :    4 x    4, 2 channel, deep float openexr
     Software: "OpenImageIO 2.5.0.0spi : oiiotool -pattern constant:color=1e38,0 4x4 2 --chnames Z,A --point:color=10.0,1.0 2,2 --deepen -o tinydeep.exr"
     version: 1
     Exif:ImageHistory: "oiiotool -pattern constant:color=1e38,0 4x4 2 --chnames Z,A --point:color=10.0,1.0 2,2 --deepen -o tinydeep.exr"
-    oiio:ColorSpace: "lin_rec709"
     oiio:subimages: 1
     openexr:chunkCount: 4
     Stats Min: 1.000000 10.000000 (float)
@@ -247,7 +246,6 @@ src/tinydeep.exr     :    4 x    4, 2 channel, deep float openexr
     Software: "OpenImageIO 2.5.0.0spi : oiiotool -pattern constant:color=1e38,0 4x4 2 --chnames Z,A --point:color=10.0,1.0 2,2 --deepen -o tinydeep.exr"
     version: 1
     Exif:ImageHistory: "oiiotool -pattern constant:color=1e38,0 4x4 2 --chnames Z,A --point:color=10.0,1.0 2,2 --deepen -o tinydeep.exr"
-    oiio:ColorSpace: "lin_rec709"
     oiio:subimages: 1
     openexr:chunkCount: 4
     Pixel (0, 0): 0 samples 

testsuite/iinfo/ref/out.txt

@@ -212,7 +212,6 @@ src/tinydeep.exr :    4 x    4, 2 channel, deep float openexr
     Software: "OpenImageIO 2.5.0.0spi : oiiotool -pattern constant:color=1e38,0 4x4 2 --chnames Z,A --point:color=10.0,1.0 2,2 --deepen -o tinydeep.exr"
     version: 1
     Exif:ImageHistory: "oiiotool -pattern constant:color=1e38,0 4x4 2 --chnames Z,A --point:color=10.0,1.0 2,2 --deepen -o tinydeep.exr"
-    oiio:ColorSpace: "lin_rec709"
     oiio:subimages: 1
     openexr:chunkCount: 4
     Stats Min: 1.000000 10.000000 (float)
@@ -247,7 +246,6 @@ src/tinydeep.exr     :    4 x    4, 2 channel, deep float openexr
     Software: "OpenImageIO 2.5.0.0spi : oiiotool -pattern constant:color=1e38,0 4x4 2 --chnames Z,A --point:color=10.0,1.0 2,2 --deepen -o tinydeep.exr"
     version: 1
     Exif:ImageHistory: "oiiotool -pattern constant:color=1e38,0 4x4 2 --chnames Z,A --point:color=10.0,1.0 2,2 --deepen -o tinydeep.exr"
-    oiio:ColorSpace: "lin_rec709"
     oiio:subimages: 1
     openexr:chunkCount: 4
     Pixel (0, 0): 0 samples 

testsuite/maketx/ref/out-macarm.txt

@@ -435,7 +435,6 @@ bumpslope.exr        :   64 x   64, 6 channel, half openexr
     uvslopes_scale: 0
     wrapmodes: "black,black"
     oiio:AverageColor: "0.499779,-0.000457942,-4.17233e-05,0.00197116,0.00178894,3.45764e-05"
-    oiio:ColorSpace: "lin_rec709"
     oiio:SHA-1: "49B533110A914CE89BE0B14753A6A4CC037C964F"
     oiio:subimages: 1
     openexr:roundingmode: 0
@@ -456,7 +455,6 @@ cdf.exr              :   64 x   64, 1 channel, half openexr
     textureformat: "Plain Texture"
     wrapmodes: "black,black"
     oiio:AverageColor: "0.499779"
-    oiio:ColorSpace: "lin_rec709"
     oiio:SHA-1: "00DFB31D0260CC466CDCF9FE42446D4896E655FE"
     oiio:subimages: 1
     openexr:roundingmode: 0
@@ -488,7 +486,6 @@ bumpslope-cdf.exr    :   64 x   64, 6 channel, half openexr
     uvslopes_scale: 0
     wrapmodes: "black,black"
     oiio:AverageColor: "0.499779,-0.000457942,-4.17233e-05,0.00197116,0.00178894,3.45764e-05"
-    oiio:ColorSpace: "lin_rec709"
     oiio:SHA-1: "49B533110A914CE89BE0B14753A6A4CC037C964F"
     oiio:subimages: 1
     openexr:roundingmode: 0

testsuite/maketx/ref/out.txt

@@ -435,7 +435,6 @@ bumpslope.exr        :   64 x   64, 6 channel, half openexr
     uvslopes_scale: 0
     wrapmodes: "black,black"
     oiio:AverageColor: "0.499779,-0.000457942,-4.17233e-05,0.00197116,0.00178894,3.45764e-05"
-    oiio:ColorSpace: "lin_rec709"
     oiio:SHA-1: "49B533110A914CE89BE0B14753A6A4CC037C964F"
     oiio:subimages: 1
     openexr:roundingmode: 0
@@ -456,7 +455,6 @@ cdf.exr              :   64 x   64, 1 channel, half openexr
     textureformat: "Plain Texture"
     wrapmodes: "black,black"
     oiio:AverageColor: "0.499779"
-    oiio:ColorSpace: "lin_rec709"
     oiio:SHA-1: "00DFB31D0260CC466CDCF9FE42446D4896E655FE"
     oiio:subimages: 1
     openexr:roundingmode: 0
@@ -488,7 +486,6 @@ bumpslope-cdf.exr    :   64 x   64, 6 channel, half openexr
     uvslopes_scale: 0
     wrapmodes: "black,black"
     oiio:AverageColor: "0.499779,-0.000457942,-4.17233e-05,0.00197116,0.00178894,3.45764e-05"
-    oiio:ColorSpace: "lin_rec709"
     oiio:SHA-1: "49B533110A914CE89BE0B14753A6A4CC037C964F"
     oiio:subimages: 1
     openexr:roundingmode: 0

testsuite/oiiotool-deep/ref/out-fmt6.txt

@@ -12,7 +12,6 @@ allhalf.exr          :  160 x  120, 2 channel, deep half openexr
     version: 1
     worldToCamera: 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, -1, 0, 1.5, 0, 4, 1
     worldToNDC: 2.41421, 0, 0, 0, 0, 3.21895, 0, 0, 0, 0, -1.00671, -1, 3.62132, 0, 3.92617, 4
-    oiio:ColorSpace: "lin_rec709"
     oiio:subimages: 1
     openexr:chunkCount: 6
     Stats Min: 0.011902 3.031250 (float)
@@ -56,7 +55,6 @@ swaptypes.exr        :  160 x  120, 2 channel, deep float/half openexr
     version: 1
     worldToCamera: 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, -1, 0, 1.5, 0, 4, 1
     worldToNDC: 2.41421, 0, 0, 0, 0, 3.21895, 0, 0, 0, 0, -1.00671, -1, 3.62132, 0, 3.92617, 4
-    oiio:ColorSpace: "lin_rec709"
     oiio:subimages: 1
     openexr:chunkCount: 6
     Stats Min: 0.011902 3.031250 (float)
@@ -95,7 +93,6 @@ tinydeep.exr         :    4 x    4, 2 channel, deep float openexr
     screenWindowCenter: 0, 0
     screenWindowWidth: 1
     version: 1
-    oiio:ColorSpace: "lin_rec709"
     oiio:subimages: 1
     openexr:chunkCount: 4
     Pixel (0, 0): 0 samples 

testsuite/oiiotool-deep/ref/out.txt

@@ -12,7 +12,6 @@ allhalf.exr          :  160 x  120, 2 channel, deep half openexr
     version: 1
     worldToCamera: 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, -1, 0, 1.5, 0, 4, 1
     worldToNDC: 2.41421, 0, 0, 0, 0, 3.21895, 0, 0, 0, 0, -1.00671, -1, 3.62132, 0, 3.92617, 4
-    oiio:ColorSpace: "lin_rec709"
     oiio:subimages: 1
     openexr:chunkCount: 6
     Stats Min: 0.011902 3.031250 (float)
@@ -56,7 +55,6 @@ swaptypes.exr        :  160 x  120, 2 channel, deep float/half openexr
     version: 1
     worldToCamera: 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, -1, 0, 1.5, 0, 4, 1
     worldToNDC: 2.41421, 0, 0, 0, 0, 3.21895, 0, 0, 0, 0, -1.00671, -1, 3.62132, 0, 3.92617, 4
-    oiio:ColorSpace: "lin_rec709"
     oiio:subimages: 1
     openexr:chunkCount: 6
     Stats Min: 0.011902 3.031250 (float)
@@ -95,7 +93,6 @@ tinydeep.exr         :    4 x    4, 2 channel, deep float openexr
     screenWindowCenter: 0, 0
     screenWindowWidth: 1
     version: 1
-    oiio:ColorSpace: "lin_rec709"
     oiio:subimages: 1
     openexr:chunkCount: 4
     Pixel (0, 0): 0 samples 

testsuite/oiiotool-maketx/ref/out-rhel7.txt

@@ -553,7 +553,6 @@ bumpslope-cdf.exr    :   64 x   64, 6 channel, half openexr
     uvslopes_scale: 0
     wrapmodes: "black,black"
     oiio:AverageColor: "0.499779,-0.000457942,-4.17233e-05,0.00197116,0.00178894,3.45764e-05"
-    oiio:ColorSpace: "lin_rec709"
     oiio:SHA-1: "49B533110A914CE89BE0B14753A6A4CC037C964F"
     oiio:subimages: 1
     openexr:roundingmode: 0

testsuite/oiiotool-maketx/ref/out-win.txt

@@ -598,7 +598,6 @@ bumpslope-cdf.exr    :   64 x   64, 6 channel, half openexr
     uvslopes_scale: 0
     wrapmodes: "black,black"
     oiio:AverageColor: "0.499779,-0.000457942,-4.17233e-05,0.00197116,0.00178894,3.45764e-05"
-    oiio:ColorSpace: "lin_rec709"
     oiio:SHA-1: "49B533110A914CE89BE0B14753A6A4CC037C964F"
     oiio:subimages: 1
     openexr:roundingmode: 0

testsuite/oiiotool-maketx/ref/out.txt

@@ -598,7 +598,6 @@ bumpslope-cdf.exr    :   64 x   64, 6 channel, half openexr
     uvslopes_scale: 0
     wrapmodes: "black,black"
     oiio:AverageColor: "0.499779,-0.000457942,-4.17233e-05,0.00197116,0.00178894,3.45764e-05"
-    oiio:ColorSpace: "lin_rec709"
     oiio:SHA-1: "49B533110A914CE89BE0B14753A6A4CC037C964F"
     oiio:subimages: 1
     openexr:roundingmode: 0

testsuite/openexr-chroma/ref/out.txt

@@ -35,7 +35,6 @@ Reading ../openexr-images/LuminanceChroma/Garden.exr
     PixelAspectRatio: 1
     screenWindowCenter: 0, 0
     screenWindowWidth: 1
-    oiio:ColorSpace: "lin_rec709"
     oiio:subimages: 1
 Comparing "../openexr-images/LuminanceChroma/Garden.exr" and "Garden.exr"
 PASS

testsuite/openexr-multires/ref/out.txt

@@ -290,7 +290,6 @@ Reading ../openexr-images/MultiView/Fog.exr
     screenWindowWidth: 1
     XResolution: 100
     YResolution: 100
-    oiio:ColorSpace: "lin_rec709"
     oiio:subimages: 1
 Comparing "../openexr-images/MultiView/Fog.exr" and "Fog.exr"
 PASS

testsuite/openexr-suite/ref/out.txt

@@ -185,7 +185,6 @@ Reading ../openexr-images/TestImages/GrayRampsDiagonal.exr
     PixelAspectRatio: 1
     screenWindowCenter: 0, 0
     screenWindowWidth: 1
-    oiio:ColorSpace: "lin_rec709"
     oiio:subimages: 1
 Comparing "../openexr-images/TestImages/GrayRampsDiagonal.exr" and "GrayRampsDiagonal.exr"
 PASS
@@ -197,7 +196,6 @@ Reading ../openexr-images/TestImages/GrayRampsHorizontal.exr
     PixelAspectRatio: 1
     screenWindowCenter: 0, 0
     screenWindowWidth: 1
-    oiio:ColorSpace: "lin_rec709"
     oiio:subimages: 1
 Comparing "../openexr-images/TestImages/GrayRampsHorizontal.exr" and "GrayRampsHorizontal.exr"
 PASS
@@ -246,7 +244,6 @@ Reading ../openexr-images/TestImages/WideFloatRange.exr
     PixelAspectRatio: 1
     screenWindowCenter: 0, 0
     screenWindowWidth: 1
-    oiio:ColorSpace: "lin_rec709"
     oiio:subimages: 1
 Comparing "../openexr-images/TestImages/WideFloatRange.exr" and "WideFloatRange.exr"
 PASS

testsuite/openexr-v2/ref/out.txt

@@ -32,7 +32,6 @@ Reading ../openexr-images/v2/Stereo/composited.exr
     screenWindowCenter: 0, 0
     screenWindowWidth: 1
     view: "left"
-    oiio:ColorSpace: "lin_rec709"
     oiio:subimagename: "depth.left"
     oiio:subimages: 4
     openexr:chunkCount: 1078
@@ -66,7 +65,6 @@ Reading ../openexr-images/v2/Stereo/composited.exr
     screenWindowCenter: 0, 0
     screenWindowWidth: 1
     view: "right"
-    oiio:ColorSpace: "lin_rec709"
     oiio:subimagename: "depth.right"
     oiio:subimages: 4
     openexr:chunkCount: 1078
@@ -231,7 +229,6 @@ Reading ../openexr-images/Beachball/multipart.0001.exr
     screenWindowCenter: 0, 0
     screenWindowWidth: 1
     view: "left"
-    oiio:ColorSpace: "lin_rec709"
     oiio:subimagename: "depth_left"
     oiio:subimages: 10
     openexr:chunkCount: 876
@@ -247,7 +244,6 @@ Reading ../openexr-images/Beachball/multipart.0001.exr
     screenWindowCenter: 0, 0
     screenWindowWidth: 1
     view: "left"
-    oiio:ColorSpace: "lin_rec709"
     oiio:subimagename: "forward_left"
     oiio:subimages: 10
     openexr:chunkCount: 876
@@ -263,7 +259,6 @@ Reading ../openexr-images/Beachball/multipart.0001.exr
     screenWindowCenter: 0, 0
     screenWindowWidth: 1
     view: "left"
-    oiio:ColorSpace: "lin_rec709"
     oiio:subimagename: "whitebarmask_left"
     oiio:subimages: 10
     openexr:chunkCount: 769
@@ -295,7 +290,6 @@ Reading ../openexr-images/Beachball/multipart.0001.exr
     screenWindowCenter: 0, 0
     screenWindowWidth: 1
     view: "right"
-    oiio:ColorSpace: "lin_rec709"
     oiio:subimagename: "depth_right"
     oiio:subimages: 10
     openexr:chunkCount: 876
@@ -311,7 +305,6 @@ Reading ../openexr-images/Beachball/multipart.0001.exr
     screenWindowCenter: 0, 0
     screenWindowWidth: 1
     view: "right"
-    oiio:ColorSpace: "lin_rec709"
     oiio:subimagename: "forward_right"
     oiio:subimages: 10
     openexr:chunkCount: 876
@@ -326,7 +319,6 @@ Reading ../openexr-images/Beachball/multipart.0001.exr
     PixelAspectRatio: 1
     screenWindowCenter: 0, 0
     screenWindowWidth: 1
-    oiio:ColorSpace: "lin_rec709"
     oiio:subimagename: "disparityL"
     oiio:subimages: 10
     openexr:chunkCount: 876
@@ -341,7 +333,6 @@ Reading ../openexr-images/Beachball/multipart.0001.exr
     PixelAspectRatio: 1
     screenWindowCenter: 0, 0
     screenWindowWidth: 1
-    oiio:ColorSpace: "lin_rec709"
     oiio:subimagename: "disparityR"
     oiio:subimages: 10
     openexr:chunkCount: 876
@@ -357,7 +348,6 @@ Reading ../openexr-images/Beachball/multipart.0001.exr
     screenWindowCenter: 0, 0
     screenWindowWidth: 1
     view: "right"
-    oiio:ColorSpace: "lin_rec709"
     oiio:subimagename: "whitebarmask_right"
     oiio:subimages: 10
     openexr:chunkCount: 769