From 959034cec386965f41a781c3ae6929bf7b14318c Mon Sep 17 00:00:00 2001
From: Carl Hetherington <cth@carlh.net>
Date: Sat, 10 Sep 2022 18:18:45 +0200
Subject: [PATCH] Use atomic for _dcp_decode_reduction.

---
 src/lib/player.cc | 17 ++++++-----------
 src/lib/player.h  |  2 +-
 2 files changed, 7 insertions(+), 12 deletions(-)

diff --git a/src/lib/player.cc b/src/lib/player.cc
index a6cfd9367..c3fee45b4 100644
--- a/src/lib/player.cc
+++ b/src/lib/player.cc
@@ -1414,19 +1414,14 @@ Player::set_dcp_decode_reduction (optional<int> reduction)
 {
 	Change (ChangeType::PENDING, PlayerProperty::DCP_DECODE_REDUCTION, false);
 
-	{
-		boost::mutex::scoped_lock lm (_mutex);
-
-		if (reduction == _dcp_decode_reduction) {
-			lm.unlock ();
-			Change (ChangeType::CANCELLED, PlayerProperty::DCP_DECODE_REDUCTION, false);
-			return;
-		}
-
-		_dcp_decode_reduction = reduction;
-		setup_pieces_unlocked ();
+	if (reduction == _dcp_decode_reduction.load()) {
+		Change(ChangeType::CANCELLED, PlayerProperty::DCP_DECODE_REDUCTION, false);
+		return;
 	}
 
+	_dcp_decode_reduction = reduction;
+	setup_pieces();
+
 	Change (ChangeType::DONE, PlayerProperty::DCP_DECODE_REDUCTION, false);
 }
 
diff --git a/src/lib/player.h b/src/lib/player.h
index d586622c4..ce8b7cc5a 100644
--- a/src/lib/player.h
+++ b/src/lib/player.h
@@ -196,7 +196,7 @@ private:
 	/** Time of the next audio that we will emit, or the time of the last accurate seek */
 	boost::optional<dcpomatic::DCPTime> _next_audio_time;
 
-	boost::optional<int> _dcp_decode_reduction;
+	boost::atomic<boost::optional<int>> _dcp_decode_reduction;
 
 	typedef std::map<std::weak_ptr<Piece>, std::shared_ptr<PlayerVideo>, std::owner_less<std::weak_ptr<Piece>>> LastVideoMap;
 	LastVideoMap _last_video;
-- 
2.30.2