add VU and IEC meter DSP (from jmeters)

1 files changed, 89 insertions, 0 deletions

diff --git a/libs/ardour/vumeterdsp.cc b/libs/ardour/vumeterdsp.cc
new file mode 100644
index 0000000000..67d48f6c54
--- /dev/null
+++ b/libs/ardour/vumeterdsp.cc
@@ -0,0 +1,89 @@
+/*
+    Copyright (C) 2012 Fons Adriaensen <fons@linuxaudio.org>
+    Adopted for Ardour 2013 by Robin Gareus <robin@gareus.org>
+
+    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 <math.h>
+#include "ardour/vumeterdsp.h"
+
+
+float Vumeterdsp::_w;
+float Vumeterdsp::_g;
+
+
+Vumeterdsp::Vumeterdsp (void) :
+    _z1 (0),
+    _z2 (0),
+    _m (0),
+    _res (true)
+{
+}
+
+
+Vumeterdsp::~Vumeterdsp (void)
+{
+}
+
+
+void Vumeterdsp::process (float *p, int n)
+{
+    float z1, z2, m, t1, t2;
+
+    z1 = _z1;
+    z2 = _z2;
+    m = _res ? 0: _m;
+    _res = false;
+
+    n /= 4;
+    while (n--)
+    {
+	t2 = z2 / 2;
+	t1 = fabsf (*p++) - t2;
+	z1 += _w * (t1 - z1);
+	t1 = fabsf (*p++) - t2;
+	z1 += _w * (t1 - z1);
+	t1 = fabsf (*p++) - t2;
+	z1 += _w * (t1 - z1);
+	t1 = fabsf (*p++) - t2;
+	z1 += _w * (t1 - z1);
+	z2 += 4 * _w * (z1 - z2);
+	if (z2 > m) m = z2;
+    }
+
+    _z1 = z1;
+    _z2 = z2 + 1e-10f;
+    _m = m;
+}
+
+
+float Vumeterdsp::read (void)
+{
+    _res = true;
+    return _g * _m;
+}
+
+void Vumeterdsp::reset ()
+{
+    _z1 = _z2 = _m = .0f;
+    _res = true;
+}
+
+void Vumeterdsp::init (float fsamp)
+{
+    _w = 11.1f / fsamp; 
+    _g = 1.5f * 1.571f;
+}