libs/ardour/meter.cc

   1 /*
   2     Copyright (C) 2006 Paul Davis
   3
   4     This program is free software; you can redistribute it and/or modify it
   5     under the terms of the GNU General Public License as published by the Free
   6     Software Foundation; either version 2 of the License, or (at your option)
   7     any later version.
   8
   9     This program is distributed in the hope that it will be useful, but WITHOUT
  10     ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11     FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12     for more details.
  13
  14     You should have received a copy of the GNU General Public License along
  15     with this program; if not, write to the Free Software Foundation, Inc.,
  16     675 Mass Ave, Cambridge, MA 02139, USA.
  17 */
  18
  19 #include <ardour/meter.h>
  20 #include <algorithm>
  21 #include <cmath>
  22 #include <ardour/buffer_set.h>
  23 #include <ardour/peak.h>
  24 #include <ardour/dB.h>
  25 #include <ardour/session.h>
  26
  27 namespace ARDOUR {
  28
  29
  30 /** Get peaks from @a bufs
  31  * Input acceptance is lenient - the first n audio buffers from @a bufs will
  32  * be metered, where n was set by the last call to setup(), excess meters will
  33  * be set to 0.
  34  */
  35 void
  36 PeakMeter::run (BufferSet& bufs, jack_nframes_t nframes, jack_nframes_t offset)
  37 {
  38         size_t meterable = std::min(bufs.count().get(DataType::AUDIO), _peak_power.size());
  39
  40         // Meter what we have
  41         for (size_t n = 0; n < meterable; ++n) {
  42                 _peak_power[n] = compute_peak (bufs.get_audio(n).data(nframes, offset), nframes, _peak_power[n]);
  43         }
  44
  45         // Zero any excess peaks
  46         for (size_t n = meterable; n < _peak_power.size(); ++n) {
  47                 _peak_power[n] = 0;
  48         }
  49 }
  50
  51 void
  52 PeakMeter::reset ()
  53 {
  54         for (size_t i = 0; i < _peak_power.size(); ++i) {
  55                 _peak_power[i] = 0;
  56         }
  57 }
  58
  59 void
  60 PeakMeter::reset_max ()
  61 {
  62         for (size_t i = 0; i < _max_peak_power.size(); ++i) {
  63                 _max_peak_power[i] = -INFINITY;
  64         }
  65 }
  66
  67 void
  68 PeakMeter::setup (const ChanCount& in)
  69 {
  70         uint32_t limit = in.get(DataType::AUDIO);
  71
  72         while (_peak_power.size() > limit) {
  73                 _peak_power.pop_back();
  74                 _visible_peak_power.pop_back();
  75                 _max_peak_power.pop_back();
  76         }
  77
  78         while (_peak_power.size() < limit) {
  79                 _peak_power.push_back(0);
  80                 _visible_peak_power.push_back(minus_infinity());
  81                 _max_peak_power.push_back(minus_infinity());
  82         }
  83
  84         assert(_peak_power.size() == limit);
  85         assert(_visible_peak_power.size() == limit);
  86         assert(_max_peak_power.size() == limit);
  87 }
  88
  89 /** To be driven by the Meter signal from IO.
  90  * Caller MUST hold io_lock!
  91  */
  92 void
  93 PeakMeter::meter ()
  94 {
  95         assert(_visible_peak_power.size() == _peak_power.size());
  96
  97         const size_t limit = _peak_power.size();
  98
  99         for (size_t n = 0; n < limit; ++n) {
 100
 101                 /* XXX we should use atomic exchange here */
 102
 103                 /* grab peak since last read */
 104
 105                 float new_peak = _peak_power[n];
 106                 _peak_power[n] = 0;
 107
 108                 /* compute new visible value using falloff */
 109
 110                 if (new_peak > 0.0) {
 111                         new_peak = coefficient_to_dB (new_peak);
 112                 } else {
 113                         new_peak = minus_infinity();
 114                 }
 115
 116                 /* update max peak */
 117
 118                 _max_peak_power[n] = std::max (new_peak, _max_peak_power[n]);
 119
 120                 if (Config->get_meter_falloff() == 0.0f || new_peak > _visible_peak_power[n]) {
 121                         _visible_peak_power[n] = new_peak;
 122                 } else {
 123                         // do falloff
 124                         new_peak = _visible_peak_power[n] - Config->get_meter_falloff();
 125                         _visible_peak_power[n] = std::max (new_peak, -INFINITY);
 126                 }
 127         }
 128 }
 129
 130 } // namespace ARDOUR