Fix incorrect colours with "no colourspace conversion" sources that are not AV_PIX_FMT_XYZ12LE.

Prepare the image for where it is going to next.  I don't understand the difference
in this situation between XYZ12LE and RGB48LE (it seems they are both 16-bit-per-channel)
but there you go.

1 files changed, 39 insertions, 0 deletions

diff --git a/test/3042_regression_test.cc b/test/3042_regression_test.cc
new file mode 100644
index 000000000..000fb6001
--- /dev/null
+++ b/test/3042_regression_test.cc
@@ -0,0 +1,39 @@
+/*
+    Copyright (C) 2025 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/>.
+
+*/
+
+
+#include "lib/content_factory.h"
+#include "lib/film.h"
+#include "lib/video_content.h"
+#include "test.h"
+#include <boost/test/unit_test.hpp>
+
+
+BOOST_AUTO_TEST_CASE(encode_xyz_from_prores_test)
+{
+	auto content = content_factory(TestPaths::private_data() / "dcp-o-matic_test_20250521_p3d65.mov")[0];
+	auto film = new_test_film("encode_xyz_from_prores_test", { content });
+	content->video->unset_colour_conversion();
+
+	make_and_verify_dcp(film);
+
+	check_one_frame(film->dir(film->dcp_name()), 0, TestPaths::private_data() / "dcp-o-matic_test_20250521_p3d65_frame0.j2c", 18);
+}
+