Obey requests to change the video range of RGB content.

Video that comes in with RGB pixels will not have its video level
ranges changed by libswscale (it only does this for YUV and greyscale).
Here we add code to do it ourselves for RGB content coming in
via image files (e.g. PNG/DPX etc).  Part of #1851.

1 files changed, 97 insertions, 0 deletions

diff --git a/test/video_level_test.cc b/test/video_level_test.cc
new file mode 100644
index 000000000..2849910b1
--- /dev/null
+++ b/test/video_level_test.cc
@@ -0,0 +1,97 @@
+/*
+    Copyright (C) 2020 Carl Hetherington <cth@carlh.net>
+
+    This file is part of DCP-o-matic.
+
+    DCP-o-matic is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 2 of the License, or
+    (at your option) any later version.
+
+    DCP-o-matic is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with DCP-o-matic.  If not, see <http://www.gnu.org/licenses/>.
+
+*/
+
+
+/** @file  test/video_level_test.cc
+ *  @brief Test that video level ranges are handled correctly.
+ *  @ingroup specific
+ */
+
+
+#include "lib/ffmpeg_image_proxy.h"
+#include "lib/image.h"
+#include "test.h"
+#include <boost/test/unit_test.hpp>
+
+
+using boost::shared_ptr;
+
+
+static
+shared_ptr<Image>
+grey_image (dcp::Size size, uint8_t pixel)
+{
+	shared_ptr<Image> grey(new Image(AV_PIX_FMT_RGB24, size, true));
+	for (int y = 0; y < size.height; ++y) {
+		uint8_t* p = grey->data()[0] + y * grey->stride()[0];
+		for (int x = 0; x < size.width; ++x) {
+			*p++ = pixel;
+			*p++ = pixel;
+			*p++ = pixel;
+		}
+	}
+
+	return grey;
+}
+
+
+BOOST_AUTO_TEST_CASE (ffmpeg_image_full_range_not_changed)
+{
+	dcp::Size size(640, 480);
+	uint8_t const grey_pixel = 128;
+	boost::filesystem::path const file = "build/test/ffmpeg_image_full_range_not_changed.png";
+
+	write_image (grey_image(size, grey_pixel), file);
+
+	FFmpegImageProxy proxy (file, VIDEO_RANGE_FULL);
+	ImageProxy::Result result = proxy.image ();
+	BOOST_REQUIRE (!result.error);
+
+	for (int y = 0; y < size.height; ++y) {
+		uint8_t* p = result.image->data()[0] + y * result.image->stride()[0];
+		for (int x = 0; x < size.width; ++x) {
+			BOOST_REQUIRE (*p++ == grey_pixel);
+		}
+	}
+}
+
+
+BOOST_AUTO_TEST_CASE (ffmpeg_image_video_range_expanded)
+{
+	dcp::Size size(640, 480);
+	uint8_t const grey_pixel = 128;
+	uint8_t const expanded_grey_pixel = static_cast<uint8_t>((grey_pixel - 16) * 256.0 / 219);
+	boost::filesystem::path const file = "build/test/ffmpeg_image_video_range_expanded.png";
+
+	write_image (grey_image(size, grey_pixel), file);
+
+	FFmpegImageProxy proxy (file, VIDEO_RANGE_VIDEO);
+	ImageProxy::Result result = proxy.image ();
+	BOOST_REQUIRE (!result.error);
+
+	for (int y = 0; y < size.height; ++y) {
+		uint8_t* p = result.image->data()[0] + y * result.image->stride()[0];
+		for (int x = 0; x < size.width; ++x) {
+			BOOST_REQUIRE_EQUAL (*p++, expanded_grey_pixel);
+		}
+	}
+}
+
+