From c56e99cd098d4bd59bc3db94e0a34d18090d93e8 Mon Sep 17 00:00:00 2001
From: Paul Davis <paul@linuxaudiosystems.com>
Date: Mon, 27 Apr 2020 15:02:22 -0600
Subject: nominal improvement for MTC master: use port latency to adjust
 sampletimes that MTC events "occured at"

---
 libs/ardour/mtc_slave.cc | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

(limited to 'libs/ardour/mtc_slave.cc')

diff --git a/libs/ardour/mtc_slave.cc b/libs/ardour/mtc_slave.cc
index b73742d7f9..848e972244 100644
--- a/libs/ardour/mtc_slave.cc
+++ b/libs/ardour/mtc_slave.cc
@@ -70,6 +70,10 @@ MTC_TransportMaster::MTC_TransportMaster (std::string const & name)
 	, printed_timecode_warning (false)
 {
 	init ();
+
+	resync_latency();
+
+	AudioEngine::instance()->GraphReordered.connect_same_thread (port_connections, boost::bind (&MTC_TransportMaster::resync_latency, this));
 }
 
 MTC_TransportMaster::~MTC_TransportMaster()
@@ -88,6 +92,16 @@ MTC_TransportMaster::init ()
 	reset (true);
 }
 
+void
+MTC_TransportMaster::resync_latency()
+{
+	DEBUG_TRACE (DEBUG::MTC, "MTC resync_latency()\n");
+
+	if (_port) {
+		_port->get_connected_latency_range (mtc_slave_latency, false);
+	}
+}
+
 void
 MTC_TransportMaster::create_port ()
 {
@@ -129,6 +143,8 @@ MTC_TransportMaster::pre_process (MIDI::pframes_t nframes, samplepos_t now, boos
 
 	maybe_reset ();
 
+	now -= mtc_slave_latency.max;
+
 	_midi_port->read_and_parse_entire_midi_buffer_with_no_speed_adjustment (nframes, parser, now);
 
 	if (session_pos) {
-- 
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