libs/ardour/amp.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 <cstring>
  20 #include <cmath>
  21 #include <algorithm>
  22 #include "ardour/amp.h"
  23 #include "ardour/audio_buffer.h"
  24 #include "ardour/buffer_set.h"
  25 #include "ardour/configuration.h"
  26 #include "ardour/io.h"
  27 #include "ardour/session.h"
  28
  29 namespace ARDOUR {
  30
  31 Amp::Amp(Session& s, IO& io)
  32         : Processor(s, "Amp")
  33         , _io(io)
  34         , _mute(false)
  35         , _apply_gain(true)
  36         , _apply_gain_automation(false)
  37         , _current_gain(1.0)
  38         , _desired_gain(1.0)
  39 {
  40 }
  41
  42 bool
  43 Amp::can_support_io_configuration (const ChanCount& in, ChanCount& out) const
  44 {
  45         out = in;
  46         return true;
  47 }
  48
  49 bool
  50 Amp::configure_io (ChanCount in, ChanCount out)
  51 {
  52         if (out != in) { // always 1:1
  53                 return false;
  54         }
  55
  56         return Processor::configure_io (in, out);
  57 }
  58
  59 void
  60 Amp::run_in_place (BufferSet& bufs, nframes_t start_frame, nframes_t end_frame, nframes_t nframes)
  61 {
  62         gain_t* gab = _session.gain_automation_buffer();
  63
  64         if (_mute && !bufs.is_silent()) {
  65                 Amp::apply_gain (bufs, nframes, _current_mute_gain, _desired_mute_gain, false);
  66                 if (_desired_mute_gain == 0.0f) {
  67                         bufs.is_silent(true);
  68                 }
  69         }
  70
  71         if (_apply_gain) {
  72
  73                 if (_apply_gain_automation) {
  74
  75                         if (_io.phase_invert()) {
  76                                 for (BufferSet::audio_iterator i = bufs.audio_begin(); i != bufs.audio_end(); ++i) {
  77                                         Sample* const sp = i->data();
  78                                         for (nframes_t nx = 0; nx < nframes; ++nx) {
  79                                                 sp[nx] *= -gab[nx];
  80                                         }
  81                                 }
  82                         } else {
  83                                 for (BufferSet::audio_iterator i = bufs.audio_begin(); i != bufs.audio_end(); ++i) {
  84                                         Sample* const sp = i->data();
  85                                         for (nframes_t nx = 0; nx < nframes; ++nx) {
  86                                                 sp[nx] *= gab[nx];
  87                                         }
  88                                 }
  89                         }
  90
  91                 } else { /* manual (scalar) gain */
  92
  93                         if (_current_gain != _desired_gain) {
  94
  95                                 Amp::apply_gain (bufs, nframes, _current_gain, _desired_gain, _io.phase_invert());
  96                                 _current_gain = _desired_gain;
  97
  98                         } else if (_current_gain != 0.0f && (_io.phase_invert() || _current_gain != 1.0f)) {
  99
 100                                 /* no need to interpolate current gain value,
 101                                    but its non-unity, so apply it. if the gain
 102                                    is zero, do nothing because we'll ship silence
 103                                    below.
 104                                 */
 105
 106                                 gain_t this_gain;
 107
 108                                 if (_io.phase_invert()) {
 109                                         this_gain = -_current_gain;
 110                                 } else {
 111                                         this_gain = _current_gain;
 112                                 }
 113
 114                                 for (BufferSet::audio_iterator i = bufs.audio_begin(); i != bufs.audio_end(); ++i) {
 115                                         Sample* const sp = i->data();
 116                                         apply_gain_to_buffer(sp, nframes, this_gain);
 117                                 }
 118
 119                         } else if (_current_gain == 0.0f) {
 120                                 for (BufferSet::audio_iterator i = bufs.audio_begin(); i != bufs.audio_end(); ++i) {
 121                                         i->clear();
 122                                 }
 123                         }
 124                 }
 125         }
 126 }
 127
 128 /** Apply a declicked gain to the audio buffers of @a bufs */
 129 void
 130 Amp::apply_gain (BufferSet& bufs, nframes_t nframes,
 131                 gain_t initial, gain_t target, bool invert_polarity)
 132 {
 133         if (nframes == 0) {
 134                 return;
 135         }
 136
 137         if (bufs.count().n_audio() == 0) {
 138                 return;
 139         }
 140
 141         // if we don't need to declick, defer to apply_simple_gain
 142         if (initial == target) {
 143                 if (target == 0.0) {
 144                         for (BufferSet::audio_iterator i = bufs.audio_begin(); i != bufs.audio_end(); ++i) {
 145                                 memset (i->data(), 0, sizeof (Sample) * nframes);
 146                         }
 147                 } else if (target != 1.0) {
 148                         for (BufferSet::audio_iterator i = bufs.audio_begin(); i != bufs.audio_end(); ++i) {
 149                                 apply_gain_to_buffer (i->data(), nframes, target);
 150                         }
 151                 }
 152                 return;
 153         }
 154
 155         const nframes_t declick = std::min ((nframes_t)128, nframes);
 156         gain_t         delta;
 157         double         fractional_shift = -1.0/declick;
 158         double         fractional_pos;
 159         gain_t         polscale = invert_polarity ? -1.0f : 1.0f;
 160
 161         if (target < initial) {
 162                 /* fade out: remove more and more of delta from initial */
 163                 delta = -(initial - target);
 164         } else {
 165                 /* fade in: add more and more of delta from initial */
 166                 delta = target - initial;
 167         }
 168
 169         for (BufferSet::audio_iterator i = bufs.audio_begin(); i != bufs.audio_end(); ++i) {
 170                 Sample* const buffer = i->data();
 171
 172                 fractional_pos = 1.0;
 173
 174                 for (nframes_t nx = 0; nx < declick; ++nx) {
 175                         buffer[nx] *= polscale * (initial + (delta * (0.5 + 0.5 * cos (M_PI * fractional_pos))));
 176                         fractional_pos += fractional_shift;
 177                 }
 178
 179                 /* now ensure the rest of the buffer has the target value applied, if necessary. */
 180
 181                 if (declick != nframes) {
 182
 183                         if (invert_polarity) {
 184                                 target = -target;
 185                         }
 186
 187                         if (target == 0.0) {
 188                                 memset (&buffer[declick], 0, sizeof (Sample) * (nframes - declick));
 189                         } else if (target != 1.0) {
 190                                 apply_gain_to_buffer (&buffer[declick], nframes - declick, target);
 191                         }
 192                 }
 193         }
 194 }
 195
 196 void
 197 Amp::apply_simple_gain (BufferSet& bufs, nframes_t nframes, gain_t target)
 198 {
 199 }
 200
 201 XMLNode&
 202 Amp::state (bool full_state)
 203 {
 204         return get_state();
 205 }
 206
 207 XMLNode&
 208 Amp::get_state()
 209 {
 210         XMLNode* node = new XMLNode(state_node_name);
 211         node->add_property("type", "amp");
 212         return *node;
 213 }
 214
 215 } // namespace ARDOUR