1 files changed, 110 insertions, 0 deletions
diff --git a/libs/ardour/meter.cc b/libs/ardour/meter.cc
new file mode 100644
index 0000000000..c574ff0bdb
--- /dev/null
+++ b/libs/ardour/meter.cc
@@ -0,0 +1,110 @@
+/*
+    Copyright (C) 2006 Paul Davis 
+    
+    This program is free software; you can redistribute it and/or modify it
+    under the terms of the GNU General Public License as published by the Free
+    Software Foundation; either version 2 of the License, or (at your option)
+    any later version.
+    
+    This program is distributed in the hope that it will be useful, but WITHOUT
+    ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+    FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+    for more details.
+    
+    You should have received a copy of the GNU General Public License along
+    with this program; if not, write to the Free Software Foundation, Inc.,
+    675 Mass Ave, Cambridge, MA 02139, USA.
+*/
+
+#include <ardour/meter.h>
+#include <algorithm>
+#include <cmath>
+#include <ardour/buffer_set.h>
+#include <ardour/peak.h>
+#include <ardour/dB.h>
+#include <ardour/session.h>
+
+namespace ARDOUR {
+
+
+/** Get peaks from @a bufs
+ * Input acceptance is lenient - the first n audio buffers from @a bufs will
+ * be metered, where n was set by the last call to setup(), excess meters will
+ * be set to 0.
+ */
+void
+PeakMeter::run (BufferSet& bufs, jack_nframes_t nframes, jack_nframes_t offset)
+{
+	size_t meterable = std::min(bufs.count().get(DataType::AUDIO), _peak_power.size());
+
+	// Meter what we have
+	for (size_t n = 0; n < meterable; ++n) {
+		_peak_power[n] = compute_peak (bufs.get_audio(n).data(nframes, offset), nframes, _peak_power[n]); 
+	}
+
+	// Zero any excess peaks
+	for (size_t n = meterable; n < _peak_power.size(); ++n) {
+		_peak_power[n] = 0;
+	}
+}
+
+void
+PeakMeter::reset ()
+{
+	for (size_t i = 0; i < _peak_power.size(); ++i) {
+		_peak_power[i] = 0;
+	}
+}
+
+void
+PeakMeter::setup (const ChanCount& in)
+{
+	uint32_t limit = in.get(DataType::AUDIO);
+
+	while (_peak_power.size() < limit) {
+		_peak_power.push_back (0);
+		_visible_peak_power.push_back (0);
+	}
+
+	assert(_peak_power.size() == limit);
+	assert(_visible_peak_power.size() == limit);
+}
+
+/** To be driven by the Meter signal from IO.
+ * Caller MUST hold io_lock!
+ */
+void
+PeakMeter::meter ()
+{
+	assert(_visible_peak_power.size() == _peak_power.size());
+
+	const size_t limit = _peak_power.size();
+
+	for (size_t n = 0; n < limit; ++n) {
+
+		/* XXX we should use atomic exchange here */
+
+		/* grab peak since last read */
+
+ 		float new_peak = _peak_power[n];
+		_peak_power[n] = 0;
+		
+		/* compute new visible value using falloff */
+
+		if (new_peak > 0.0) {
+			new_peak = coefficient_to_dB (new_peak);
+		} else {
+			new_peak = minus_infinity();
+		}
+		
+		if (_session.meter_falloff() == 0.0f || new_peak > _visible_peak_power[n]) {
+			_visible_peak_power[n] = new_peak;
+		} else {
+			// do falloff
+			new_peak = _visible_peak_power[n] - _session.meter_falloff();
+			_visible_peak_power[n] = std::max (new_peak, -INFINITY);
+		}
+	}
+}
+
+} // namespace ARDOUR