From 7904ba56bba3a107087546b09139b60544f5c272 Mon Sep 17 00:00:00 2001
From: Carl Hetherington <cth@carlh.net>
Date: Fri, 5 Jun 2020 00:07:29 +0200
Subject: [PATCH] Fix crash when previewing projects with fewer than 6 audio
 channels; the old code tried to copy audio just because its channel had a
 non-0 value in the map without checking whether the destination channel
 actually existed.

---
 src/lib/util.cc | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/lib/util.cc b/src/lib/util.cc
index e0efbc6f5..f9877523a 100644
--- a/src/lib/util.cc
+++ b/src/lib/util.cc
@@ -823,7 +823,9 @@ remap (shared_ptr<const AudioBuffers> input, int output_channels, AudioMapping m
 	shared_ptr<AudioBuffers> mapped (new AudioBuffers (output_channels, input->frames()));
 	mapped->make_silent ();
 
-	for (int i = 0; i < map.input_channels(); ++i) {
+	int to_do = min (map.input_channels(), input->channels());
+
+	for (int i = 0; i < to_do; ++i) {
 		for (int j = 0; j < mapped->channels(); ++j) {
 			if (map.get (i, static_cast<dcp::Channel> (j)) > 0) {
 				mapped->accumulate_channel (
-- 
2.30.2