src/lib/audio_merger.cc

   1 /*
   2     Copyright (C) 2013-2017 Carl Hetherington <cth@carlh.net>
   3
   4     This program is free software; you can redistribute it and/or modify
   5     it under the terms of the GNU General Public License as published by
   6     the Free Software Foundation; either version 2 of the License, or
   7     (at your option) any later version.
   8
   9     This program is distributed in the hope that it will be useful,
  10     but WITHOUT ANY WARRANTY; without even the implied warranty of
  11     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12     GNU General Public License for more details.
  13
  14     You should have received a copy of the GNU General Public License
  15     along with this program; if not, write to the Free Software
  16     Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  17
  18 */
  19
  20 /** @file  src/audio_merger.cc
  21  *  @brief AudioMerger class.
  22  */
  23
  24 #include "audio_merger.h"
  25 #include "dcpomatic_time.h"
  26 #include <iostream>
  27
  28 using std::pair;
  29 using std::min;
  30 using std::max;
  31 using std::list;
  32 using std::cout;
  33 using std::make_pair;
  34 using boost::shared_ptr;
  35 using boost::optional;
  36
  37 // #define INSTRUMENT 1
  38
  39 AudioMerger::AudioMerger (int frame_rate)
  40         : _frame_rate (frame_rate)
  41 {
  42 #ifdef INSTRUMENT
  43         cout << "I/AM frame_rate " << frame_rate << "\n";
  44 #endif
  45 }
  46
  47 Frame
  48 AudioMerger::frames (DCPTime t) const
  49 {
  50         return t.frames_floor (_frame_rate);
  51 }
  52
  53 /** Pull audio up to a given time; after this call, no more data can be pushed
  54  *  before the specified time.
  55  *  @param time Time to pull up to.
  56  *  @return Blocks of merged audio up to `time'.
  57  */
  58 list<pair<shared_ptr<AudioBuffers>, DCPTime> >
  59 AudioMerger::pull (DCPTime time)
  60 {
  61 #ifdef INSTRUMENT
  62         std::cout << "I/AM pull " << time.get() << "\n";
  63 #endif
  64         list<pair<shared_ptr<AudioBuffers>, DCPTime> > out;
  65
  66         list<Buffer> new_buffers;
  67
  68         _buffers.sort (AudioMerger::BufferComparator());
  69         BOOST_FOREACH (Buffer i, _buffers) {
  70                 if (i.period().to <= time) {
  71                         /* Completely within the pull period */
  72                         DCPOMATIC_ASSERT (i.audio->frames() > 0);
  73                         out.push_back (make_pair (i.audio, i.time));
  74                 } else if (i.time < time) {
  75                         /* Overlaps the end of the pull period */
  76                         shared_ptr<AudioBuffers> audio (new AudioBuffers (i.audio->channels(), frames(DCPTime(time - i.time))));
  77                         /* Though time > i.time, audio->frames() could be 0 if the difference in time is less than one frame */
  78                         if (audio->frames() > 0) {
  79                                 audio->copy_from (i.audio.get(), audio->frames(), 0, 0);
  80                                 out.push_back (make_pair (audio, i.time));
  81                                 i.audio->trim_start (audio->frames ());
  82                                 i.time += DCPTime::from_frames(audio->frames(), _frame_rate);
  83                                 DCPOMATIC_ASSERT (i.audio->frames() > 0);
  84                                 new_buffers.push_back (i);
  85                         }
  86                 } else {
  87                         /* Not involved */
  88                         DCPOMATIC_ASSERT (i.audio->frames() > 0);
  89                         new_buffers.push_back (i);
  90                 }
  91         }
  92
  93         _buffers = new_buffers;
  94
  95         for (list<pair<shared_ptr<AudioBuffers>, DCPTime> >::const_iterator i = out.begin(); i != out.end(); ++i) {
  96                 DCPOMATIC_ASSERT (i->first->frames() > 0);
  97         }
  98
  99         return out;
 100 }
 101
 102 /** Push some data into the merger at a given time */
 103 void
 104 AudioMerger::push (boost::shared_ptr<const AudioBuffers> audio, DCPTime time)
 105 {
 106 #ifdef INSTRUMENT
 107         std::cout << "I/AM push " << time.get() << " " << audio->frames() << "\n";
 108 #endif
 109         DCPOMATIC_ASSERT (audio->frames() > 0);
 110
 111         DCPTimePeriod period (time, time + DCPTime::from_frames (audio->frames(), _frame_rate));
 112
 113         /* Mix any overlapping parts of this new block with existing ones */
 114         BOOST_FOREACH (Buffer i, _buffers) {
 115                 optional<DCPTimePeriod> overlap = i.period().overlap (period);
 116                 if (overlap) {
 117                         int32_t const offset = frames(DCPTime(overlap->from - i.time));
 118                         int32_t const frames_to_mix = frames(overlap->duration());
 119                         if (i.time < time) {
 120                                 i.audio->accumulate_frames(audio.get(), frames_to_mix, 0, offset);
 121                         } else {
 122                                 i.audio->accumulate_frames(audio.get(), frames_to_mix, offset, 0);
 123                         }
 124                 }
 125         }
 126
 127         list<DCPTimePeriod> periods;
 128         BOOST_FOREACH (Buffer i, _buffers) {
 129                 periods.push_back (i.period ());
 130         }
 131
 132         /* Add the non-overlapping parts */
 133         BOOST_FOREACH (DCPTimePeriod i, subtract (period, periods)) {
 134                 list<Buffer>::iterator before = _buffers.end();
 135                 list<Buffer>::iterator after = _buffers.end();
 136                 for (list<Buffer>::iterator j = _buffers.begin(); j != _buffers.end(); ++j) {
 137                         if (j->period().to == i.from) {
 138                                 before = j;
 139                         }
 140                         if (j->period().from == i.to) {
 141                                 after = j;
 142                         }
 143                 }
 144
 145                 /* Get the part of audio that we want to use */
 146                 shared_ptr<AudioBuffers> part (new AudioBuffers (audio->channels(), frames(i.to) - frames(i.from)));
 147                 part->copy_from (audio.get(), part->frames(), frames(DCPTime(i.from - time)), 0);
 148
 149                 if (before == _buffers.end() && after == _buffers.end()) {
 150                         /* New buffer */
 151                         DCPOMATIC_ASSERT (part->frames() > 0);
 152                         _buffers.push_back (Buffer (part, time, _frame_rate));
 153                 } else if (before != _buffers.end() && after == _buffers.end()) {
 154                         /* We have an existing buffer before this one; append new data to it */
 155                         before->audio->append (part);
 156                 } else if (before ==_buffers.end() && after != _buffers.end()) {
 157                         /* We have an existing buffer after this one; append it to the new data and replace */
 158                         part->append (after->audio);
 159                         after->audio = part;
 160                         after->time = time;
 161                 } else {
 162                         /* We have existing buffers both before and after; coalesce them all */
 163                         before->audio->append (part);
 164                         before->audio->append (after->audio);
 165                         _buffers.erase (after);
 166                 }
 167         }
 168 }
 169
 170 void
 171 AudioMerger::clear ()
 172 {
 173 #ifdef INSTRUMENT
 174         cout << "I/AM clear\n";
 175 #endif
 176         _buffers.clear ();
 177 }