From 8c4819e58830adc85a831a38dbec54c682d9b348 Mon Sep 17 00:00:00 2001
From: Robin Gareus <robin@gareus.org>
Date: Thu, 15 Aug 2024 17:52:48 +0200
Subject: [PATCH] AU: request offline processing

---
 libs/ardour/ardour/audio_unit.h |  2 ++
 libs/ardour/audio_unit.cc       | 33 +++++++++++++++++++++++++++++++++
 2 files changed, 35 insertions(+)

diff --git a/libs/ardour/ardour/audio_unit.h b/libs/ardour/ardour/audio_unit.h
index 757a771282..6ce63b00c9 100644
--- a/libs/ardour/ardour/audio_unit.h
+++ b/libs/ardour/ardour/audio_unit.h
@@ -81,6 +81,7 @@ class LIBARDOUR_API AUPlugin : public ARDOUR::Plugin
 	void deactivate ();
 	void flush ();
 	int set_block_size (pframes_t nframes);
+	void set_non_realtime (bool);
 
 	int connect_and_run (BufferSet& bufs,
 			samplepos_t start, samplepos_t end, double speed,
@@ -166,6 +167,7 @@ class LIBARDOUR_API AUPlugin : public ARDOUR::Plugin
 	std::shared_ptr<CAAudioUnit> unit;
 
 	bool initialized;
+	bool process_offline;
 	int32_t input_channels;
 	int32_t output_channels;
 	std::vector<std::pair<int,int> > io_configs;
diff --git a/libs/ardour/audio_unit.cc b/libs/ardour/audio_unit.cc
index 781a4e8783..f94f7a1be9 100644
--- a/libs/ardour/audio_unit.cc
+++ b/libs/ardour/audio_unit.cc
@@ -360,6 +360,7 @@ AUPlugin::AUPlugin (AudioEngine& engine, Session& session, std::shared_ptr<CACom
 	, comp (_comp)
 	, unit (new CAAudioUnit)
 	, initialized (false)
+	, process_offline (false)
 	, _last_nframes (0)
 	, _requires_fixed_size_buffers (false)
 	, buffers (0)
@@ -401,6 +402,7 @@ AUPlugin::AUPlugin (const AUPlugin& other)
 	, comp (other.get_comp())
 	, unit (new CAAudioUnit)
 	, initialized (false)
+	, process_offline (false)
 	, _last_nframes (0)
 	, _requires_fixed_size_buffers (false)
 	, buffers (0)
@@ -869,6 +871,33 @@ AUPlugin::requires_fixed_size_buffers() const
 	return _requires_fixed_size_buffers;
 }
 
+void
+AUPlugin::set_non_realtime (bool yn)
+{
+	if (process_offline == yn) {
+		return;
+	}
+	process_offline = yn;
+
+	bool was_initialized = initialized;
+	if (initialized) {
+		deactivate ();
+	}
+
+	OSErr err;
+	UInt32 isOffline = yn ? 1 : 0;
+	if ((err = unit->SetProperty (/*kAudioUnitProperty_OfflineRender*/ 37, kAudioUnitScope_Global, 0, &isOffline, sizeof (isOffline))) != noErr) {
+		info << string_compose (_("AU: cannot set offline rendering(err = %1)"), err) << endmsg;
+	}
+	if (yn) {
+		UInt32 numSamples = _session.get_block_size();
+		unit->SetProperty (/*kAudioUnitOfflineProperty_InputSize*/ 3020, kAudioUnitScope_Global, 0, &numSamples, sizeof(numSamples));
+	}
+
+	if (was_initialized) {
+		activate ();
+	}
+}
 
 int
 AUPlugin::set_block_size (pframes_t nframes)
@@ -888,6 +917,10 @@ AUPlugin::set_block_size (pframes_t nframes)
 		return -1;
 	}
 
+	if (process_offline) {
+		unit->SetProperty (/*kAudioUnitOfflineProperty_InputSize*/ 3020, kAudioUnitScope_Global, 0, &numSamples, sizeof(numSamples));
+	}
+
 	if (was_initialized) {
 		activate ();
 	}