Fix MPEG2 DCP gamma (#3026).3026-mpeg2-colour

5 files changed, 48 insertions, 1 deletions

diff --git a/src/lib/colour_conversion.cc b/src/lib/colour_conversion.cc
index b5d6cd4c5..5dc633f60 100644
--- a/src/lib/colour_conversion.cc
+++ b/src/lib/colour_conversion.cc
@@ -138,6 +138,12 @@ ColourConversion::ColourConversion(cxml::NodePtr node, int version)
 	} else {
 		_out_j2k = make_shared<dcp::IdentityTransferFunction>();
 	}
+
+	if (auto mpeg2_gamma = node->optional_number_child<double>("OutputMPEG2Gamma")) {
+		_out_mpeg2 = make_shared<dcp::GammaTransferFunction>(*mpeg2_gamma);
+	} else {
+		_out_mpeg2 = make_shared<dcp::IdentityTransferFunction>();
+	}
 }
 
 boost::optional<ColourConversion>
@@ -186,6 +192,10 @@ ColourConversion::as_xml(xmlpp::Element* element) const
 	if (auto gf = dynamic_pointer_cast<const dcp::GammaTransferFunction>(_out_j2k)) {
 		cxml::add_text_child(element, "OutputGamma", fmt::to_string(gf->gamma()));
 	}
+
+	if (auto gf = dynamic_pointer_cast<const dcp::GammaTransferFunction>(_out_mpeg2)) {
+		cxml::add_text_child(element, "OutputMPEG2Gamma", fmt::to_string(gf->gamma()));
+	}
 }
 
 optional<size_t>
@@ -240,6 +250,10 @@ ColourConversion::identifier() const
 		digester.add(gf->gamma());
 	}
 
+	if (auto gf = dynamic_pointer_cast<const dcp::GammaTransferFunction>(_out_mpeg2)) {
+		digester.add(gf->gamma());
+	}
+
 	return digester.get();
 }
 
diff --git a/src/lib/mpeg2_encoder.cc b/src/lib/mpeg2_encoder.cc
index 38388431d..c9ee6c491 100644
--- a/src/lib/mpeg2_encoder.cc
+++ b/src/lib/mpeg2_encoder.cc
@@ -22,6 +22,7 @@
 #include "mpeg2_encoder.h"
 #include "writer.h"
 #include <dcp/ffmpeg_image.h>
+#include <dcp/transfer_function.h>
 extern "C" {
 #include <libavutil/pixfmt.h>
 }
@@ -43,7 +44,24 @@ MPEG2Encoder::encode(shared_ptr<PlayerVideo> pv, dcpomatic::DCPTime time)
 {
 	VideoEncoder::encode(pv, time);
 
-	auto image = pv->image(force(AV_PIX_FMT_YUV420P), VideoRange::VIDEO, false);
+	shared_ptr<Image> image;
+
+	if (auto conversion = pv->colour_conversion()) {
+		if (!conversion->in()->about_equal(conversion->out_mpeg2(), 0.05)) {
+			image = pv->image([](AVPixelFormat) { return AV_PIX_FMT_RGB24; }, VideoRange::VIDEO, Image::Alignment::PADDED, false);
+			dcp::convert_rgb_gamma(image->data()[0], image->size(), image->stride()[0], *conversion);
+			image = image->convert_pixel_format(conversion->yuv_to_rgb(), AV_PIX_FMT_YUV420P, Image::Alignment::COMPACT, false);
+		}
+	}
+
+	if (!image) {
+		image = pv->image(
+			[](AVPixelFormat) { return AV_PIX_FMT_YUV420P; },
+			VideoRange::VIDEO,
+			Image::Alignment::COMPACT,
+			false
+			);
+	}
 
 	dcp::FFmpegImage ffmpeg_image(time.get() * _film->video_frame_rate() / dcpomatic::DCPTime::HZ);
 
diff --git a/src/wx/colour_conversion_editor.cc b/src/wx/colour_conversion_editor.cc
index a16b7066f..83dbf67b7 100644
--- a/src/wx/colour_conversion_editor.cc
+++ b/src/wx/colour_conversion_editor.cc
@@ -216,6 +216,10 @@ ColourConversionEditor::ColourConversionEditor (wxWindow* parent, bool yuv)
 	table->Add(_output_j2k, wxGBPosition(r, 0), wxGBSpan(1, 2));
 	++r;
 
+	_output_mpeg2 = new CheckBox(this, _("Inverse 2.4 gamma correction on output to MPEG2"));
+	table->Add(_output_mpeg2, wxGBPosition(r, 0), wxGBSpan(1, 2));
+	++r;
+
 	_input_gamma->SetRange (0.1, 4.0);
 	_input_gamma->SetDigits (2);
 	_input_gamma->SetIncrement (0.1);
@@ -242,6 +246,7 @@ ColourConversionEditor::ColourConversionEditor (wxWindow* parent, bool yuv)
 	_adjusted_white_y->Bind (wxEVT_TEXT, bind (&ColourConversionEditor::adjusted_white_changed, this));
 	_yuv_to_rgb->Bind (wxEVT_CHOICE, bind (&ColourConversionEditor::changed, this));
 	_output_j2k->bind(&ColourConversionEditor::changed, this);
+	_output_mpeg2->bind(&ColourConversionEditor::changed, this);
 }
 
 
@@ -313,6 +318,7 @@ ColourConversionEditor::set (ColourConversion conversion)
 	}
 
 	_output_j2k->SetValue(static_cast<bool>(dynamic_pointer_cast<const dcp::GammaTransferFunction>(conversion.out_j2k())));
+	_output_mpeg2->SetValue(static_cast<bool>(dynamic_pointer_cast<const dcp::GammaTransferFunction>(conversion.out_mpeg2())));
 
 	update_rgb_to_xyz ();
 	update_bradford ();
@@ -380,6 +386,12 @@ ColourConversionEditor::get () const
 		conversion.set_out_j2k(make_shared<dcp::IdentityTransferFunction>());
 	}
 
+	if (_output_mpeg2->GetValue()) {
+		conversion.set_out_mpeg2(make_shared<dcp::GammaTransferFunction>(2.4));
+	} else {
+		conversion.set_out_mpeg2(make_shared<dcp::IdentityTransferFunction>());
+	}
+
 	return conversion;
 }
 
diff --git a/src/wx/colour_conversion_editor.h b/src/wx/colour_conversion_editor.h
index ac2273540..6ec524992 100644
--- a/src/wx/colour_conversion_editor.h
+++ b/src/wx/colour_conversion_editor.h
@@ -83,6 +83,7 @@ private:
 	wxTextCtrl* _adjusted_white_x;
 	wxTextCtrl* _adjusted_white_y;
 	CheckBox* _output_j2k;
+	CheckBox* _output_mpeg2;
 	wxStaticText* _rgb_to_xyz[3][3];
 	wxStaticText* _bradford[3][3];
 };
diff --git a/test/colour_conversion_test.cc b/test/colour_conversion_test.cc
index db33a2b37..765ad491a 100644
--- a/test/colour_conversion_test.cc
+++ b/test/colour_conversion_test.cc
@@ -74,6 +74,7 @@ BOOST_AUTO_TEST_CASE (colour_conversion_test2)
 		"  <WhiteX>0.3127</WhiteX>\n"
 		"  <WhiteY>0.329</WhiteY>\n"
 		"  <OutputGamma>2.6</OutputGamma>\n"
+		"  <OutputMPEG2Gamma>2.4</OutputMPEG2Gamma>\n"
 		"</Test>\n"
 		);
 }
@@ -103,6 +104,7 @@ BOOST_AUTO_TEST_CASE (colour_conversion_test3)
 		"  <WhiteX>0.3127</WhiteX>\n"
 		"  <WhiteY>0.329</WhiteY>\n"
 		"  <OutputGamma>2.6</OutputGamma>\n"
+		"  <OutputMPEG2Gamma>2.4</OutputMPEG2Gamma>\n"
 		"</Test>\n"
 		);
 }