From 1809b6ae9aadaa3af0c1577b9bf3c88551060827 Mon Sep 17 00:00:00 2001
From: Robin Gareus <robin@gareus.org>
Date: Tue, 10 May 2022 05:38:38 +0200
Subject: [PATCH] Reset port resampler after freewheeling

This clears out any data potently left there by export processing.
Previously this could cause an audible click.
---
 libs/ardour/ardour/audio_port.h   | 4 ++++
 libs/ardour/ardour/port.h         | 1 +
 libs/ardour/ardour/port_manager.h | 2 ++
 libs/ardour/audio_port.cc         | 6 ++++++
 libs/ardour/audioengine.cc        | 3 +++
 libs/ardour/port_manager.cc       | 7 +++++++
 6 files changed, 23 insertions(+)

diff --git a/libs/ardour/ardour/audio_port.h b/libs/ardour/ardour/audio_port.h
index c9eaab0259..419d067d54 100644
--- a/libs/ardour/ardour/audio_port.h
+++ b/libs/ardour/ardour/audio_port.h
@@ -42,6 +42,9 @@ public:
 	void cycle_end (pframes_t);
 	void cycle_split ();
 
+	/* reset SRC, clear out any state */
+	void reinit ();
+
 	Buffer& get_buffer (pframes_t nframes) {
 		return get_audio_buffer (nframes);
 	}
@@ -53,6 +56,7 @@ protected:
 	friend class PortManager;
 	AudioPort (std::string const &, PortFlags);
 
+
 	/* special access for PortManager only (hah, C++) */
 	Sample* engine_get_whole_audio_buffer ();
 
diff --git a/libs/ardour/ardour/port.h b/libs/ardour/ardour/port.h
index 9e6bcc2bf0..eaaed6c16d 100644
--- a/libs/ardour/ardour/port.h
+++ b/libs/ardour/ardour/port.h
@@ -121,6 +121,7 @@ public:
 	virtual void cycle_start (pframes_t);
 	virtual void cycle_end (pframes_t) = 0;
 	virtual void cycle_split () = 0;
+	virtual void reinit () {}
 	virtual Buffer& get_buffer (pframes_t nframes) = 0;
 	virtual void flush_buffers (pframes_t /*nframes*/) {}
 	virtual void transport_stopped () {}
diff --git a/libs/ardour/ardour/port_manager.h b/libs/ardour/ardour/port_manager.h
index ecef697de9..922e6be174 100644
--- a/libs/ardour/ardour/port_manager.h
+++ b/libs/ardour/ardour/port_manager.h
@@ -293,6 +293,8 @@ protected:
 	 */
 	void cycle_end (pframes_t nframes, Session* s = 0);
 
+	void reinit ();
+
 	void cycle_end_fade_out (gain_t, gain_t, pframes_t, Session* s = 0);
 
 	static std::string port_info_file ();
diff --git a/libs/ardour/audio_port.cc b/libs/ardour/audio_port.cc
index 313eeadf29..615173fe95 100644
--- a/libs/ardour/audio_port.cc
+++ b/libs/ardour/audio_port.cc
@@ -127,6 +127,12 @@ AudioPort::cycle_split ()
 {
 }
 
+void
+AudioPort::reinit ()
+{
+	_src.reset ();
+}
+
 AudioBuffer&
 AudioPort::get_audio_buffer (pframes_t nframes)
 {
diff --git a/libs/ardour/audioengine.cc b/libs/ardour/audioengine.cc
index 59b3650955..7ced5d813e 100644
--- a/libs/ardour/audioengine.cc
+++ b/libs/ardour/audioengine.cc
@@ -1483,6 +1483,9 @@ AudioEngine::freewheel_callback (bool onoff)
 {
 	DEBUG_TRACE (DEBUG::BackendCallbacks, string_compose (X_("freewheel callback onoff %1\n"), onoff));
 	_freewheeling = onoff;
+	if (!_freewheeling) {
+		PortManager::reinit ();
+	}
 }
 
 void
diff --git a/libs/ardour/port_manager.cc b/libs/ardour/port_manager.cc
index 260ac21080..1186150153 100644
--- a/libs/ardour/port_manager.cc
+++ b/libs/ardour/port_manager.cc
@@ -1183,6 +1183,13 @@ PortManager::silence (pframes_t nframes, Session* s)
 		}
 	}
 }
+void
+PortManager::reinit ()
+{
+	for (auto const& p : *_ports.reader ()) {
+		p.second->reinit ();
+	}
+}
 
 void
 PortManager::silence_outputs (pframes_t nframes)