libs/ardour/delayline.cc

   1 /*
   2     Copyright (C) 2006, 2013 Paul Davis
   3     Copyright (C) 2013, 2014 Robin Gareus <robin@gareus.org>
   4
   5     This program is free software; you can redistribute it and/or modify it
   6     under the terms of the GNU General Public License as published by the Free
   7     Software Foundation; either version 2 of the License, or (at your option)
   8     any later version.
   9
  10     This program is distributed in the hope that it will be useful, but WITHOUT
  11     ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  12     FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  13     for more details.
  14
  15     You should have received a copy of the GNU General Public License along
  16     with this program; if not, write to the Free Software Foundation, Inc.,
  17     675 Mass Ave, Cambridge, MA 02139, USA.
  18 */
  19
  20 #include <assert.h>
  21 #include <cmath>
  22
  23 #include "pbd/compose.h"
  24
  25 #include "ardour/debug.h"
  26 #include "ardour/audio_buffer.h"
  27 #include "ardour/midi_buffer.h"
  28 #include "ardour/buffer_set.h"
  29 #include "ardour/delayline.h"
  30
  31 using namespace std;
  32 using namespace PBD;
  33 using namespace ARDOUR;
  34
  35 DelayLine::DelayLine (Session& s, const std::string& name)
  36     : Processor (s, string_compose ("latency-compensation-%1", name))
  37                 , _delay(0)
  38                 , _pending_delay(0)
  39                 , _bsiz(0)
  40                 , _pending_bsiz(0)
  41                 , _roff(0)
  42                 , _woff(0)
  43                 , _pending_flush(false)
  44 {
  45 }
  46
  47 DelayLine::~DelayLine ()
  48 {
  49 }
  50
  51 #define FADE_LEN (16)
  52 void
  53 DelayLine::run (BufferSet& bufs, framepos_t /* start_frame */, framepos_t /* end_frame */, pframes_t nsamples, bool)
  54 {
  55         const uint32_t chn = _configured_output.n_audio();
  56         pframes_t p0 = 0;
  57         uint32_t c;
  58
  59         const frameoffset_t pending_delay = _pending_delay;
  60         const frameoffset_t delay_diff = _delay - pending_delay;
  61         const bool pending_flush = _pending_flush;
  62         _pending_flush = false;
  63
  64         /* run() and set_delay() may be called in parallel by
  65          * different threads.
  66          * if a larger buffer is needed, it is allocated in
  67          * set_delay(), here it is just swap'ed in place
  68          */
  69         if (_pending_bsiz) {
  70                 assert(_pending_bsiz >= _bsiz);
  71
  72                 const size_t boff = _pending_bsiz - _bsiz;
  73                 if (_bsiz > 0) {
  74                         /* write offset is retained. copy existing data to new buffer */
  75                         frameoffset_t wl = _bsiz - _woff;
  76                         memcpy(_pending_buf.get(), _buf.get(), sizeof(Sample) * _woff * chn);
  77                         memcpy(_pending_buf.get() + (_pending_bsiz - wl) * chn, _buf.get() + _woff * chn, sizeof(Sample) * wl * chn);
  78
  79                         /* new buffer is all zero by default, fade into the existing data copied above */
  80                         frameoffset_t wo = _pending_bsiz - wl;
  81                         for (pframes_t pos = 0; pos < FADE_LEN; ++pos) {
  82                                 const gain_t gain = (gain_t)pos / (gain_t)FADE_LEN;
  83                                 for (c = 0; c < _configured_input.n_audio(); ++c) {
  84                                         _pending_buf.get()[ wo * chn + c ] *= gain;
  85                                         wo = (wo + 1) % (_pending_bsiz + 1);
  86                                 }
  87                         }
  88
  89                         /* read-pointer will be moved and may up anywhere..
  90                          * copy current data for smooth fade-out below
  91                          */
  92                         frameoffset_t roold = _roff;
  93                         frameoffset_t ro = _roff;
  94                         if (ro > _woff) {
  95                                 ro += boff;
  96                         }
  97                         ro += delay_diff;
  98                         if (ro < 0) {
  99                                 ro -= (_pending_bsiz +1) * floor(ro / (float)(_pending_bsiz +1));
 100                         }
 101                         ro = ro % (_pending_bsiz + 1);
 102                         for (pframes_t pos = 0; pos < FADE_LEN; ++pos) {
 103                                 for (c = 0; c < _configured_input.n_audio(); ++c) {
 104                                         _pending_buf.get()[ ro * chn + c ] = _buf.get()[ roold * chn + c ];
 105                                         ro = (ro + 1) % (_pending_bsiz + 1);
 106                                         roold = (roold + 1) % (_bsiz + 1);
 107                                 }
 108                         }
 109                 }
 110
 111                 if (_roff > _woff) {
 112                         _roff += boff;
 113                 }
 114
 115                 _buf = _pending_buf;
 116                 _bsiz = _pending_bsiz;
 117                 _pending_bsiz = 0;
 118                 _pending_buf.reset();
 119         }
 120
 121         /* there may be no buffer when delay == 0.
 122          * we also need to check audio-channels in case all audio-channels
 123          * were removed in which case no new buffer was allocated. */
 124         Sample *buf = _buf.get();
 125         if (buf && _configured_output.n_audio() > 0) {
 126
 127                 assert (_bsiz >= pending_delay);
 128                 const framecnt_t rbs = _bsiz + 1;
 129
 130                 if (pending_delay != _delay || pending_flush) {
 131                         const pframes_t fade_len = (nsamples >= FADE_LEN) ? FADE_LEN : nsamples / 2;
 132
 133                         DEBUG_TRACE (DEBUG::LatencyCompensation,
 134                                         string_compose ("Old %1 delay: %2 bufsiz: %3 offset-diff: %4 write-offset: %5 read-offset: %6\n",
 135                                                 name(), _delay, _bsiz, ((_woff - _roff + rbs) % rbs), _woff, _roff));
 136
 137                         // fade out at old position
 138                         c = 0;
 139                         for (BufferSet::audio_iterator i = bufs.audio_begin(); i != bufs.audio_end(); ++i, ++c) {
 140                                 Sample * const data = i->data();
 141                                 for (pframes_t pos = 0; pos < fade_len; ++pos) {
 142                                         const gain_t gain = (gain_t)(fade_len - pos) / (gain_t)fade_len;
 143                                         buf[ _woff * chn + c ] = data[ pos ];
 144                                         data[ pos ] = buf[ _roff * chn + c ] * gain;
 145                                         _roff = (_roff + 1) % rbs;
 146                                         _woff = (_woff + 1) % rbs;
 147                                 }
 148                         }
 149
 150                         if (pending_flush) {
 151                                 DEBUG_TRACE (DEBUG::LatencyCompensation,
 152                                                 string_compose ("Flush buffer: %1\n", name()));
 153                                 memset(buf, 0, _configured_output.n_audio() * rbs * sizeof (Sample));
 154                         }
 155
 156                         // adjust read pointer
 157                         _roff += _delay - pending_delay;
 158
 159                         if (_roff < 0) {
 160                                 _roff -= rbs * floor(_roff / (float)rbs);
 161                         }
 162                         _roff = _roff % rbs;
 163
 164                         // fade in at new position
 165                         c = 0;
 166                         for (BufferSet::audio_iterator i = bufs.audio_begin(); i != bufs.audio_end(); ++i, ++c) {
 167                                 Sample * const data = i->data();
 168                                 for (pframes_t pos = fade_len; pos < 2 * fade_len; ++pos) {
 169                                         const gain_t gain = (gain_t)(pos - fade_len) / (gain_t)fade_len;
 170                                         buf[ _woff * chn + c ] = data[ pos ];
 171                                         data[ pos ] = buf[ _roff * chn + c ] * gain;
 172                                         _roff = (_roff + 1) % rbs;
 173                                         _woff = (_woff + 1) % rbs;
 174                                 }
 175                         }
 176                         p0  = 2 * fade_len;
 177
 178                         _delay = pending_delay;
 179
 180                         DEBUG_TRACE (DEBUG::LatencyCompensation,
 181                                         string_compose ("New %1 delay: %2 bufsiz: %3 offset-diff: %4 write-offset: %5 read-offset: %6\n",
 182                                                 name(), _delay, _bsiz, ((_woff - _roff + rbs) % rbs), _woff, _roff));
 183                 }
 184
 185                 assert(_delay == ((_woff - _roff + rbs) % rbs));
 186
 187                 c = 0;
 188                 for (BufferSet::audio_iterator i = bufs.audio_begin(); i != bufs.audio_end(); ++i, ++c) {
 189                         Sample * const data = i->data();
 190                         for (pframes_t pos = p0; pos < nsamples; ++pos) {
 191                                 buf[ _woff * chn + c ] = data[ pos ];
 192                                 data[ pos ] = buf[ _roff * chn + c ];
 193                                 _roff = (_roff + 1) % rbs;
 194                                 _woff = (_woff + 1) % rbs;
 195                         }
 196                 }
 197         }
 198
 199         if (_midi_buf.get()) {
 200                 _delay = pending_delay;
 201
 202                 for (BufferSet::midi_iterator i = bufs.midi_begin(); i != bufs.midi_end(); ++i) {
 203                         if (i != bufs.midi_begin()) { break; } // XXX only one buffer for now
 204
 205                         MidiBuffer* dly = _midi_buf.get();
 206                         MidiBuffer& mb (*i);
 207                         if (pending_flush) {
 208                                 dly->silence(nsamples);
 209                         }
 210
 211                         // If the delay time changes, iterate over all events in the dly-buffer
 212                         // and adjust the time in-place. <= 0 becomes 0.
 213                         //
 214                         // iterate over all events in dly-buffer and subtract one cycle
 215                         // (nsamples) from the timestamp, bringing them closer to de-queue.
 216                         for (MidiBuffer::iterator m = dly->begin(); m != dly->end(); ++m) {
 217                                 MidiBuffer::TimeType *t = m.timeptr();
 218                                 if (*t > nsamples + delay_diff) {
 219                                         *t -= nsamples + delay_diff;
 220                                 } else {
 221                                         *t = 0;
 222                                 }
 223                         }
 224
 225                         if (_delay != 0) {
 226                                 // delay events in current-buffer, in place.
 227                                 for (MidiBuffer::iterator m = mb.begin(); m != mb.end(); ++m) {
 228                                         MidiBuffer::TimeType *t = m.timeptr();
 229                                         *t += _delay;
 230                                 }
 231                         }
 232
 233                         // move events from dly-buffer into current-buffer until nsamples
 234                         // and remove them from the dly-buffer
 235                         for (MidiBuffer::iterator m = dly->begin(); m != dly->end();) {
 236                                 const Evoral::MIDIEvent<MidiBuffer::TimeType> ev (*m, false);
 237                                 if (ev.time() >= nsamples) {
 238                                         break;
 239                                 }
 240                                 mb.insert_event(ev);
 241                                 m = dly->erase(m);
 242                         }
 243
 244                         /* For now, this is only relevant if there is there's a positive delay.
 245                          * In the future this could also be used to delay 'too early' events
 246                          * (ie '_global_port_buffer_offset + _port_buffer_offset' - midi_port.cc)
 247                          */
 248                         if (_delay != 0) {
 249                                 // move events after nsamples from current-buffer into dly-buffer
 250                                 // and trim current-buffer after nsamples
 251                                 for (MidiBuffer::iterator m = mb.begin(); m != mb.end();) {
 252                                         const Evoral::MIDIEvent<MidiBuffer::TimeType> ev (*m, false);
 253                                         if (ev.time() < nsamples) {
 254                                                 ++m;
 255                                                 continue;
 256                                         }
 257                                         dly->insert_event(ev);
 258                                         m = mb.erase(m);
 259                                 }
 260                         }
 261                 }
 262         }
 263
 264         _delay = pending_delay;
 265 }
 266
 267 void
 268 DelayLine::set_delay(framecnt_t signal_delay)
 269 {
 270         if (signal_delay < 0) {
 271                 signal_delay = 0;
 272                 cerr << "WARNING: latency compensation is not possible.\n";
 273         }
 274
 275         const framecnt_t rbs = signal_delay + 1;
 276
 277         DEBUG_TRACE (DEBUG::LatencyCompensation,
 278                         string_compose ("%1 set_delay to %2 samples for %3 channels\n",
 279                                 name(), signal_delay, _configured_output.n_audio()));
 280
 281         if (signal_delay <= _bsiz) {
 282                 _pending_delay = signal_delay;
 283                 return;
 284         }
 285
 286         if (_pending_bsiz) {
 287                 if (_pending_bsiz < signal_delay) {
 288                         cerr << "LatComp: buffer resize in progress. "<< name() << "pending: "<< _pending_bsiz <<" want: " << signal_delay <<"\n"; // XXX
 289                 } else {
 290                         _pending_delay = signal_delay;
 291                 }
 292                 return;
 293         }
 294
 295         if (_configured_output.n_audio() > 0 ) {
 296                 _pending_buf.reset(new Sample[_configured_output.n_audio() * rbs]);
 297                 memset(_pending_buf.get(), 0, _configured_output.n_audio() * rbs * sizeof (Sample));
 298                 _pending_bsiz = signal_delay;
 299         } else {
 300                 _pending_buf.reset();
 301                 _pending_bsiz = 0;
 302         }
 303
 304         _pending_delay = signal_delay;
 305
 306         DEBUG_TRACE (DEBUG::LatencyCompensation,
 307                         string_compose ("allocated buffer for %1 of size %2\n",
 308                                 name(), signal_delay));
 309 }
 310
 311 bool
 312 DelayLine::can_support_io_configuration (const ChanCount& in, ChanCount& out)
 313 {
 314         out = in;
 315         return true;
 316 }
 317
 318 bool
 319 DelayLine::configure_io (ChanCount in, ChanCount out)
 320 {
 321         if (out != in) { // always 1:1
 322                 return false;
 323         }
 324
 325         // TODO realloc buffers if channel count changes..
 326         // TODO support multiple midi buffers
 327
 328         DEBUG_TRACE (DEBUG::LatencyCompensation,
 329                         string_compose ("configure IO: %1 Ain: %2 Aout: %3 Min: %4 Mout: %5\n",
 330                                 name(), in.n_audio(), out.n_audio(), in.n_midi(), out.n_midi()));
 331
 332         if (in.n_midi() > 0 && !_midi_buf) {
 333                 _midi_buf.reset(new MidiBuffer(16384));
 334         }
 335
 336         return Processor::configure_io (in, out);
 337 }
 338
 339 void
 340 DelayLine::flush()
 341 {
 342         _pending_flush = true;
 343 }
 344
 345 XMLNode&
 346 DelayLine::state (bool full_state)
 347 {
 348         XMLNode& node (Processor::state (full_state));
 349         node.add_property("type", "delay");
 350         return node;
 351 }