Fix decoding of SSA subs in files decoded by FFmpeg (#2904).

Suddenly we have 8 commas, not 9, perhaps because of
29412821241050c846dbceaad4b9752857659977
in ffmpeg (although that's strange, because it was a long time ago).

3 files changed, 63 insertions, 2 deletions

diff --git a/src/lib/ffmpeg_decoder.cc b/src/lib/ffmpeg_decoder.cc
index f57c9efe8..a8bfd2a38 100644
--- a/src/lib/ffmpeg_decoder.cc
+++ b/src/lib/ffmpeg_decoder.cc
@@ -816,9 +816,9 @@ FFmpegDecoder::process_ass_subtitle (string ass, ContentTime from)
 	int commas = 0;
 	string text;
 	for (size_t i = 0; i < ass.length(); ++i) {
-		if (commas < 9 && ass[i] == ',') {
+		if (commas < 8 && ass[i] == ',') {
 			++commas;
-		} else if (commas == 9) {
+		} else if (commas == 8) {
 			text += ass[i];
 		}
 	}
diff --git a/test/ffmpeg_subtitles_test.cc b/test/ffmpeg_subtitles_test.cc
new file mode 100644
index 000000000..da63063cb
--- /dev/null
+++ b/test/ffmpeg_subtitles_test.cc
@@ -0,0 +1,60 @@
+/*
+    Copyright (C) 2024 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/player.h"
+#include "lib/text_content.h"
+#include "test.h"
+#include <boost/optional.hpp>
+#include <boost/test/unit_test.hpp>
+
+
+using std::make_shared;
+using std::shared_ptr;
+using std::string;
+using std::vector;
+using boost::optional;
+
+
+BOOST_AUTO_TEST_CASE(decoding_ssa_subs_from_mkv)
+{
+	auto subs = content_factory(TestPaths::private_data() / "ssa_subs.mkv")[0];
+	auto film = new_test_film("decoding_ssa_subs_from_mkv", { subs });
+	subs->text[0]->set_use(true);
+
+	vector<string> lines;
+
+	auto player = make_shared<Player>(film, film->playlist());
+	player->Text.connect([&lines](PlayerText text, TextType, optional<DCPTextTrack>, dcpomatic::DCPTimePeriod) {
+		for (auto i: text.string) {
+			lines.push_back(i.text());
+		}
+	});
+
+	while (lines.size() <= 2 && !player->pass()) {}
+
+	BOOST_REQUIRE_EQUAL(lines.size(), 3U);
+	BOOST_CHECK_EQUAL(lines[0], "-You're hungry.");
+	BOOST_CHECK_EQUAL(lines[1], "-Unit 14, nothing's happening");
+	BOOST_CHECK_EQUAL(lines[2], "here, we're gonna go to the beach.");
+}
+
diff --git a/test/wscript b/test/wscript
index e9f24f0fe..e32ec9acb 100644
--- a/test/wscript
+++ b/test/wscript
@@ -94,6 +94,7 @@ def build(bld):
                  ffmpeg_examiner_test.cc
                  ffmpeg_properties_test.cc
                  ffmpeg_pts_offset_test.cc
+                 ffmpeg_subtitles_test.cc
                  file_group_test.cc
                  file_log_test.cc
                  file_naming_test.cc