patch from robin to fix where the transport start occurs when exporting (#4098)

git-svn-id: svn://localhost/ardour2/branches/3.0@13305 d708f5d6-7413-0410-9779-e7cbd77b26cf

1 files changed, 11 insertions, 5 deletions

diff --git a/libs/ardour/session_export.cc b/libs/ardour/session_export.cc
index 1c1b4f9a0f..969f4bb609 100644
--- a/libs/ardour/session_export.cc
+++ b/libs/ardour/session_export.cc
@@ -106,6 +106,7 @@ Session::start_audio_export (framepos_t position)
 {
 	if (!_exporting) {
 		pre_export ();
+		_export_started = false;
 	}
 
 	/* We're about to call Track::seek, so the butler must have finished everything
@@ -145,11 +146,6 @@ Session::start_audio_export (framepos_t position)
 	   since then has re-awakened it.
 	 */
 
-	set_transport_speed (1.0, false);
-	butler_transport_work ();
-	g_atomic_int_set (&_butler->should_do_transport_work, 0);
-	post_transport ();
-
 	/* we are ready to go ... */
 
 	if (!_engine.connected()) {
@@ -193,6 +189,16 @@ Session::process_export (pframes_t nframes)
 int
 Session::process_export_fw (pframes_t nframes)
 {
+
+	if (!_export_started) {
+		_export_started=true;
+		set_transport_speed (1.0, false);
+		butler_transport_work ();
+		g_atomic_int_set (&_butler->should_do_transport_work, 0);
+		post_transport ();
+		return 0;
+	}
+
         _engine.main_thread()->get_buffers ();
 	process_export (nframes);
         _engine.main_thread()->drop_buffers ();