From 8641139a1723ad36df0f6a59b364b20b291f0213 Mon Sep 17 00:00:00 2001
From: Krzysztof Foltman <wdev@foltman.com>
Date: Wed, 2 Dec 2009 21:27:48 +0000
Subject: [PATCH] + VU meter: move to separate header to enable reuse, modify
 falloff behaviour, add clipping detection

---
 src/calf/Makefile.am |  2 +-
 src/calf/jackhost.h  | 26 +-----------------
 src/calf/vumeter.h   | 74 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 76 insertions(+), 26 deletions(-)
 create mode 100644 src/calf/vumeter.h

diff --git a/src/calf/Makefile.am b/src/calf/Makefile.am
index 56963f6..48b0877 100644
--- a/src/calf/Makefile.am
+++ b/src/calf/Makefile.am
@@ -5,4 +5,4 @@ noinst_HEADERS = audio_fx.h benchmark.h biquad.h buffer.h custom_ctl.h \
     lv2_uri_map.h lv2-midiport.h lv2helpers.h lv2wrap.h \
     main_win.h metadata.h modmatrix.h modules.h modules_dev.h modules_small.h modules_synths.h modulelist.h \
     multichorus.h onepole.h organ.h osc.h osctl.h osctlnet.h osctlserv.h plugininfo.h preset.h \
-    preset_gui.h primitives.h synth.h utils.h wave.h waveshaping.h
+    preset_gui.h primitives.h synth.h utils.h vumeter.h wave.h waveshaping.h
diff --git a/src/calf/jackhost.h b/src/calf/jackhost.h
index 38b7b02..d6a1816 100644
--- a/src/calf/jackhost.h
+++ b/src/calf/jackhost.h
@@ -27,6 +27,7 @@
 #include <jack/midiport.h>
 #include "gui.h"
 #include "utils.h"
+#include "vumeter.h"
 #include <pthread.h>
 
 namespace calf_plugins {
@@ -164,31 +165,6 @@ public:
     }
 };
 
-struct vumeter
-{
-    float level, falloff;
-    
-    vumeter()
-    {
-        falloff = 0.999f;
-        level = 0;
-    }
-    
-    inline void update(float *src, unsigned int len)
-    {
-        double tmp = level;
-        for (unsigned int i = 0; i < len; i++)
-            tmp = std::max(tmp * falloff, (double)fabs(src[i]));
-        level = tmp;
-        dsp::sanitize(level);
-    }
-    inline void update_zeros(unsigned int len)
-    {
-        level *= pow((double)falloff, (double)len);
-        dsp::sanitize(level);
-    }
-};
-
 template<class Module>
 class jack_host: public jack_host_base, public Module {
 public:
diff --git a/src/calf/vumeter.h b/src/calf/vumeter.h
new file mode 100644
index 0000000..de174c1
--- /dev/null
+++ b/src/calf/vumeter.h
@@ -0,0 +1,74 @@
+/* Calf DSP Library 
+ * Peak metering facilities.
+ *
+ * Copyright (C) 2007 Krzysztof Foltman
+ *
+ * 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, 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., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+#ifndef __CALF_VUMETER_H
+#define __CALF_VUMETER_H
+
+/// Peak meter class
+struct vumeter
+{
+    /// Measured signal level
+    float level;
+    /// Falloff of signal level (b1 coefficient of a 1-pole filter)
+    float falloff;
+    /// Clip indicator (set to 1 when |value| >= 1, fading otherwise)
+    float clip;
+    /// Falloff of clip indicator (b1 coefficient of a 1-pole filter); set to 1 if no falloff is required (manual reset of clip indicator)
+    float clip_falloff;
+    
+    vumeter()
+    {
+        falloff = 0.999f;
+        level = 0;
+        clip_falloff = 0.999f;
+        clip = 0;
+    }
+    
+    /// Update peak meter based on input signal
+    inline void update(float *src, unsigned int len)
+    {
+        // "Age" the old level by falloff^length
+        float tmp = level * pow(falloff, len);
+        // Same for clip level (using different fade constant)
+        double tmp_clip = clip * pow(clip_falloff, len);
+        // Process input samples - to get peak value, take a max of all values in the input signal and "aged" old peak
+        // Clip is set to 1 if any sample is out-of-range, if no clip occurs, the "aged" value is assumed
+        for (unsigned int i = 0; i < len; i++) {
+            float sig = fabs(src[i]);
+            tmp = std::max(tmp, sig);
+            if (sig >= 1.f)
+                tmp_clip = 1.f;
+        }
+        level = tmp;
+        clip = tmp_clip;
+        dsp::sanitize(level);
+        dsp::sanitize(clip);
+    }
+    /// Update clip meter as if update was called with all-zero input signal
+    inline void update_zeros(unsigned int len)
+    {
+        level *= pow((double)falloff, (double)len);
+        clip *= pow((double)clip_falloff, (double)len);
+        dsp::sanitize(level);
+        dsp::sanitize(clip);
+    }
+};
+
+#endif
-- 
2.11.4.GIT