From aee658ef96eb77a8fac1cc70bc06e935de7c0fac Mon Sep 17 00:00:00 2001
From: Robin Gareus <robin@gareus.org>
Date: Sun, 3 May 2015 23:17:15 +0200
Subject: [PATCH] no more noise during startup.

---
 libs/ardour/audioengine.cc | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/libs/ardour/audioengine.cc b/libs/ardour/audioengine.cc
index b18d5e1af2..a92e7d4524 100644
--- a/libs/ardour/audioengine.cc
+++ b/libs/ardour/audioengine.cc
@@ -205,7 +205,12 @@ AudioEngine::process_callback (pframes_t nframes)
 		if (_session) {
 			Xrun();
 		}
-		_processed_frames = next_processed_frames;
+		/* really only JACK requires this
+		 * (other backends clear the output buffers
+		 * before the process_callback. it may even be 
+		 * jack/alsa only). but better safe than sorry.
+		 */
+		PortManager::silence_physical (nframes);
 		return 0;
 	}