X-Git-Url: https://main.carlh.net/gitweb/?a=blobdiff_plain;f=libs%2Fardour%2Faudioengine.cc;h=cbdd1fda1ce8fc088c66161295cd3775a356dd66;hb=c7e404a1c0ee9af941a335e4bdd2f667b0c6317a;hp=0bfa18be72fc03319dceb0b806e105096bef1b87;hpb=b3fe7cfc892f7d5978ad14eb81e9305fa9c14d13;p=ardour.git

diff --git a/libs/ardour/audioengine.cc b/libs/ardour/audioengine.cc
index 0bfa18be72..cbdd1fda1c 100644
--- a/libs/ardour/audioengine.cc
+++ b/libs/ardour/audioengine.cc
@@ -255,6 +255,11 @@ AudioEngine::_graph_order_callback (void *arg)
 	return 0;
 }
 
+/** Wrapped which is called by JACK as its process callback.  It is just
+ * here to get us back into C++ land by calling AudioEngine::process_callback()
+ * @param nframes Number of frames passed by JACK.
+ * @param arg User argument passed by JACK, which will be the AudioEngine*.
+ */
 int
 AudioEngine::_process_callback (nframes_t nframes, void *arg)
 {
@@ -267,11 +272,17 @@ AudioEngine::_freewheel_callback (int onoff, void *arg)
 	static_cast<AudioEngine*>(arg)->_freewheeling = onoff;
 }
 
+/** Method called by JACK (via _process_callback) which says that there
+ * is work to be done.
+ * @param nframes Number of frames to process.
+ */
 int
 AudioEngine::process_callback (nframes_t nframes)
 {
 	// CycleTimer ct ("AudioEngine::process");
 	Glib::Mutex::Lock tm (_process_lock, Glib::TRY_LOCK);
+
+	/// The number of frames that will have been processed when we've finished
 	nframes_t next_processed_frames;
 	
 	/* handle wrap around of total frames counter */
@@ -281,13 +292,15 @@ AudioEngine::process_callback (nframes_t nframes)
 	} else {
 		next_processed_frames = _processed_frames + nframes;
 	}
-	
+
 	if (!tm.locked() || session == 0) {
+		/* return having done nothing */
 		_processed_frames = next_processed_frames;
 		return 0;
 	}
 
 	if (session_remove_pending) {
+		/* perform the actual session removal */
 		session = 0;
 		session_remove_pending = false;
 		session_removed.signal();
@@ -296,6 +309,7 @@ AudioEngine::process_callback (nframes_t nframes)
 	}
 
 	if (_freewheeling) {
+		/* emit the Freewheel signal and stop freewheeling in the event of trouble */
 		if (Freewheel (nframes)) {
 			cerr << "Freewheeling returned non-zero!\n";
 			_freewheeling = false;
@@ -307,23 +321,23 @@ AudioEngine::process_callback (nframes_t nframes)
 	boost::shared_ptr<Ports> p = ports.reader();
 
 	// Prepare ports (ie read data if necessary)
-	for (Ports::iterator i = p->begin(); i != p->end(); ++i)
-		(*i)->cycle_start(nframes);
+	for (Ports::iterator i = p->begin(); i != p->end(); ++i) {
+		(*i)->cycle_start (nframes);
+	}
 	
-	session->process (nframes);
+	if (session) {
+		session->process (nframes);
+	}
 
 	if (!_running) {
-		/* we were zombified, maybe because a ladspa plugin took
-		   too long, or jackd exited, or something like that.
-		*/
-		
 		_processed_frames = next_processed_frames;
 		return 0;
 	}
 	
 	// Finalize ports (ie write data if necessary)
-	for (Ports::iterator i = p->begin(); i != p->end(); ++i)
-		(*i)->cycle_end();
+	for (Ports::iterator i = p->begin(); i != p->end(); ++i) {
+		(*i)->cycle_end ();
+	}
 
 	if (last_monitor_check + monitor_check_interval < next_processed_frames) {
 
@@ -447,14 +461,23 @@ AudioEngine::set_session (Session *s)
 		   can before we really start running.
 		*/
 		
-		session->process (blocksize);
-		session->process (blocksize);
-		session->process (blocksize);
-		session->process (blocksize);
-		session->process (blocksize);
-		session->process (blocksize);
-		session->process (blocksize);
-		session->process (blocksize);
+		boost::shared_ptr<Ports> p = ports.reader();
+
+		for (Ports::iterator i = p->begin(); i != p->end(); ++i)
+			(*i)->cycle_start (blocksize);
+
+		s->process (blocksize);
+		s->process (blocksize);
+		s->process (blocksize);
+		s->process (blocksize);
+		s->process (blocksize);
+		s->process (blocksize);
+		s->process (blocksize);
+		s->process (blocksize);
+
+		for (Ports::iterator i = p->begin(); i != p->end(); ++i)
+			(*i)->cycle_end ();
+
 	}
 }