From: Carl Hetherington <cth@carlh.net>
Date: Tue, 23 Feb 2021 19:01:49 +0000 (+0100)
Subject: Fix assertion failure in AudioBuffers::copy_from() (#1909)
X-Git-Url: https://main.carlh.net/gitweb/?p=dcpomatic.git;a=commitdiff_plain;h=4d8c69b356f770144c59982c4196846d6f1dc0b0

Fix assertion failure in AudioBuffers::copy_from() (#1909)

A number of frames N was being split up into two parts which together
were bigger than N, meaning a copy of one of the parts failed.
---

diff --git a/src/lib/writer.cc b/src/lib/writer.cc
index 9ebdd92a3..ad588f0a6 100644
--- a/src/lib/writer.cc
+++ b/src/lib/writer.cc
@@ -306,11 +306,14 @@ Writer::write (shared_ptr<const AudioBuffers> audio, DCPTime const time)
 				end - _audio_reel->period().to
 			};
 
+			/* Be careful that part_lengths[0] + part_lengths[1] can't be bigger than audio->frames() */
 			Frame part_frames[2] = {
 				part_lengths[0].frames_ceil(afr),
-				part_lengths[1].frames_ceil(afr)
+				part_lengths[1].frames_floor(afr)
 			};
 
+			DCPOMATIC_ASSERT ((part_frames[0] + part_frames[1]) <= audio->frames());
+
 			if (part_frames[0]) {
 				shared_ptr<AudioBuffers> part (new AudioBuffers(audio, part_frames[0], 0));
 				_audio_reel->write (part);
diff --git a/test/writer_test.cc b/test/writer_test.cc
new file mode 100644
index 000000000..dade4d6b4
--- /dev/null
+++ b/test/writer_test.cc
@@ -0,0 +1,49 @@
+/*
+    Copyright (C) 2021 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/audio_buffers.h"
+#include "lib/content.h"
+#include "lib/content_factory.h"
+#include "lib/film.h"
+#include "lib/job.h"
+#include "lib/video_content.h"
+#include "lib/writer.h"
+#include "test.h"
+#include <boost/test/unit_test.hpp>
+#include <memory>
+
+
+using std::make_shared;
+using std::shared_ptr;
+
+
+BOOST_AUTO_TEST_CASE (test_write_odd_amount_of_silence)
+{
+	auto content = content_factory("test/data/flat_red.png").front();
+	auto film = new_test_film2 ("test_write_odd_amount_of_silence", {content});
+	content->video->set_length(24);
+	auto writer = make_shared<Writer>(film, shared_ptr<Job>());
+
+	auto audio = make_shared<AudioBuffers>(6, 48000);
+	audio->make_silent ();
+	writer->write (audio, dcpomatic::DCPTime(1));
+}
+
diff --git a/test/wscript b/test/wscript
index cbe2c176c..4303db835 100644
--- a/test/wscript
+++ b/test/wscript
@@ -138,6 +138,7 @@ def build(bld):
                  video_level_test.cc
                  video_mxf_content_test.cc
                  vf_kdm_test.cc
+                 writer_test.cc
                  zipper_test.cc
                  """