diff --git a/libs/ardour/ardour/lv2_plugin.h b/libs/ardour/ardour/lv2_plugin.h
index 9573db6e04..c437ac79e8 100644
--- a/libs/ardour/ardour/lv2_plugin.h
+++ b/libs/ardour/ardour/lv2_plugin.h
@@ -154,6 +154,7 @@ class LIBARDOUR_API LV2Plugin : public ARDOUR::Plugin, public ARDOUR::Workee
 
 	void add_slave (std::shared_ptr<Plugin>, bool);
 	void remove_slave (std::shared_ptr<Plugin>);
+	void set_non_realtime (bool);
 
 	bool write_from_ui(uint32_t       index,
 	                   uint32_t       protocol,
@@ -226,6 +227,7 @@ class LIBARDOUR_API LV2Plugin : public ARDOUR::Plugin, public ARDOUR::Workee
 	double        _current_bpm;
 	double        _prev_time_scale;  ///< previous Port::speed_ratio
 	PBD::ID       _insert_id;
+	bool          _non_realtime;
 	std::string   _plugin_state_dir;
 	uint32_t      _bpm_control_port_index;
 	uint32_t      _patch_port_in_index;
diff --git a/libs/ardour/ardour/plugin.h b/libs/ardour/ardour/plugin.h
index 9b6dbb8d06..c855e1ae02 100644
--- a/libs/ardour/ardour/plugin.h
+++ b/libs/ardour/ardour/plugin.h
@@ -191,6 +191,9 @@ public:
 	void realtime_locate (bool);
 	void monitoring_changed ();
 
+	/* use plugin for offline processing */
+	virtual void set_non_realtime (bool) {}
+
 	virtual void add_slave (std::shared_ptr<Plugin>, bool realtime) {}
 	virtual void remove_slave (std::shared_ptr<Plugin>) {}
 
diff --git a/libs/ardour/ardour/vst3_plugin.h b/libs/ardour/ardour/vst3_plugin.h
index 96269fd3e7..6f1de4792a 100644
--- a/libs/ardour/ardour/vst3_plugin.h
+++ b/libs/ardour/ardour/vst3_plugin.h
@@ -199,6 +199,7 @@ public:
 	}
 
 	void set_owner (ARDOUR::SessionObject* o);
+	void set_non_realtime (bool);
 
 	void enable_io (std::vector<bool> const&, std::vector<bool> const&);
 
@@ -297,6 +298,7 @@ private:
 	bool    _is_loading_state;
 	bool    _is_processing;
 	int32_t _block_size;
+	bool    _process_offline;
 
 	/* ports */
 	struct Param {
@@ -426,6 +428,7 @@ public:
 	int set_block_size (pframes_t);
 
 	void set_owner (ARDOUR::SessionObject* o);
+	void set_non_realtime (bool);
 
 	void add_slave (std::shared_ptr<Plugin>, bool);
 	void remove_slave (std::shared_ptr<Plugin>);
diff --git a/libs/ardour/lv2_plugin.cc b/libs/ardour/lv2_plugin.cc
index 01aa41d36b..de50c3f8e9 100644
--- a/libs/ardour/lv2_plugin.cc
+++ b/libs/ardour/lv2_plugin.cc
@@ -453,6 +453,7 @@ LV2Plugin::LV2Plugin (AudioEngine& engine,
 	, _worker(NULL)
 	, _state_worker(NULL)
 	, _insert_id("0")
+	, _non_realtime (false)
 	, _bpm_control_port_index((uint32_t)-1)
 	, _patch_port_in_index((uint32_t)-1)
 	, _patch_port_out_index((uint32_t)-1)
@@ -472,6 +473,7 @@ LV2Plugin::LV2Plugin (const LV2Plugin& other)
 	, _worker(NULL)
 	, _state_worker(NULL)
 	, _insert_id(other._insert_id)
+	, _non_realtime (other._non_realtime)
 	, _bpm_control_port_index((uint32_t)-1)
 	, _patch_port_in_index((uint32_t)-1)
 	, _patch_port_out_index((uint32_t)-1)
@@ -1830,6 +1832,12 @@ LV2Plugin::remove_slave (std::shared_ptr<Plugin> p)
 	}
 }
 
+void
+LV2Plugin::set_non_realtime (bool yn)
+{
+	_non_realtime = yn;
+}
+
 bool
 LV2Plugin::has_message_output() const
 {
@@ -2790,7 +2798,7 @@ LV2Plugin::connect_and_run(BufferSet& bufs,
 	TempoMetric metric (tmap->metric_at (timepos_t (start0)));
 
 	if (_freewheel_control_port) {
-		*_freewheel_control_port = _session.engine().freewheeling() ? 1.f : 0.f;
+		*_freewheel_control_port = _non_realtime || _session.engine().freewheeling() ? 1.f : 0.f;
 	}
 
 	if (_bpm_control_port) {
@@ -3379,7 +3387,7 @@ LV2Plugin::run(pframes_t nframes, bool sync_work)
 
 	if (_worker) {
 		// Execute work synchronously if we're freewheeling (export)
-		_worker->set_synchronous(sync_work || session().engine().freewheeling());
+		_worker->set_synchronous(sync_work || _non_realtime || session().engine().freewheeling());
 	}
 
 	// Run the plugin for this cycle
diff --git a/libs/ardour/vst3_plugin.cc b/libs/ardour/vst3_plugin.cc
index 86b0368842..d9f6227fa9 100644
--- a/libs/ardour/vst3_plugin.cc
+++ b/libs/ardour/vst3_plugin.cc
@@ -699,6 +699,12 @@ VST3Plugin::remove_slave (std::shared_ptr<Plugin> p)
 	}
 }
 
+void
+VST3Plugin::set_non_realtime (bool yn)
+{
+	_plug->set_non_realtime (yn);
+}
+
 int
 VST3Plugin::connect_and_run (BufferSet&  bufs,
                              samplepos_t start, samplepos_t end, double speed,
@@ -1166,6 +1172,7 @@ VST3PI::VST3PI (std::shared_ptr<ARDOUR::VST3PluginModule> m, std::string unique_
 	, _is_loading_state (false)
 	, _is_processing (false)
 	, _block_size (0)
+	, _process_offline (false)
 	, _port_id_bypass (UINT32_MAX)
 	, _owner (0)
 	, _add_to_selection (false)
@@ -1764,7 +1771,7 @@ VST3PI::update_processor ()
 	}
 
 	Vst::ProcessSetup setup;
-	setup.processMode        = AudioEngine::instance ()->freewheeling () ? Vst::kOffline : Vst::kRealtime;
+	setup.processMode        = _process_offline || AudioEngine::instance ()->freewheeling () ? Vst::kOffline : Vst::kRealtime;
 	setup.symbolicSampleSize = Vst::kSample32;
 	setup.maxSamplesPerBlock = _block_size;
 	setup.sampleRate         = _context.sampleRate;
@@ -1804,6 +1811,12 @@ VST3PI::set_owner (SessionObject* o)
 	}
 }
 
+void
+VST3PI::set_non_realtime (bool yn)
+{
+	_process_offline = yn;
+}
+
 int32
 VST3PI::count_channels (Vst::MediaType media, Vst::BusDirection dir, Vst::BusType type)
 {
@@ -2315,7 +2328,7 @@ VST3PI::process (float** ins, float** outs, uint32_t n_samples)
 
 	Vst::ProcessData data;
 	data.numSamples         = n_samples;
-	data.processMode        = AudioEngine::instance ()->freewheeling () ? Vst::kOffline : Vst::kRealtime;
+	data.processMode        = _process_offline || AudioEngine::instance ()->freewheeling () ? Vst::kOffline : Vst::kRealtime;
 	data.symbolicSampleSize = Vst::kSample32;
 	data.numInputs          = _n_bus_in;
 	data.numOutputs         = _n_bus_out;