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 AudioMerger::AudioMerger (int frame_rate)
  38         : _frame_rate (frame_rate)
  39 {
  40
  41 }
  42
  43 Frame
  44 AudioMerger::frames (DCPTime t) const
  45 {
  46         return t.frames_floor (_frame_rate);
  47 }
  48
  49 /** Pull audio up to a given time; after this call, no more data can be pushed
  50  *  before the specified time.
  51  *  @param time Time to pull up to.
  52  *  @return Blocks of merged audio up to `time'.
  53  */
  54 list<pair<shared_ptr<AudioBuffers>, DCPTime> >
  55 AudioMerger::pull (DCPTime time)
  56 {
  57         list<pair<shared_ptr<AudioBuffers>, DCPTime> > out;
  58
  59         DCPTimePeriod period (_last_pull, time);
  60         _buffers.sort (AudioMerger::BufferComparator());
  61
  62         list<Buffer> new_buffers;
  63
  64         BOOST_FOREACH (Buffer i, _buffers) {
  65                 if (i.period().to <= time) {
  66                         /* Completely within the pull period */
  67                         DCPOMATIC_ASSERT (i.audio->frames() > 0);
  68                         out.push_back (make_pair (i.audio, i.time));
  69                 } else if (i.time < time) {
  70                         /* Overlaps the end of the pull period */
  71                         shared_ptr<AudioBuffers> audio (new AudioBuffers (i.audio->channels(), frames(DCPTime(time - i.time))));
  72                         /* Though time > i.time, audio->frames() could be 0 if the difference in time is less than one frame */
  73                         if (audio->frames() > 0) {
  74                                 audio->copy_from (i.audio.get(), audio->frames(), 0, 0);
  75                                 out.push_back (make_pair (audio, i.time));
  76                                 i.audio->trim_start (audio->frames ());
  77                                 i.time += DCPTime::from_frames(audio->frames(), _frame_rate);
  78                                 DCPOMATIC_ASSERT (i.audio->frames() > 0);
  79                                 new_buffers.push_back (i);
  80                         }
  81                 } else {
  82                         /* Not involved */
  83                         DCPOMATIC_ASSERT (i.audio->frames() > 0);
  84                         new_buffers.push_back (i);
  85                 }
  86         }
  87
  88         _buffers = new_buffers;
  89
  90         for (list<pair<shared_ptr<AudioBuffers>, DCPTime> >::const_iterator i = out.begin(); i != out.end(); ++i) {
  91                 DCPOMATIC_ASSERT (i->first->frames() > 0);
  92         }
  93
  94         return out;
  95 }
  96
  97 /** Push some data into the merger at a given time */
  98 void
  99 AudioMerger::push (boost::shared_ptr<const AudioBuffers> audio, DCPTime time)
 100 {
 101         DCPOMATIC_ASSERT (time >= _last_pull);
 102         DCPOMATIC_ASSERT (audio->frames() > 0);
 103
 104         DCPTimePeriod period (time, time + DCPTime::from_frames (audio->frames(), _frame_rate));
 105
 106         /* Mix any overlapping parts of this new block with existing ones */
 107         BOOST_FOREACH (Buffer i, _buffers) {
 108                 optional<DCPTimePeriod> overlap = i.period().overlap (period);
 109                 if (overlap) {
 110                         int32_t const offset = frames(DCPTime(overlap->from - i.time));
 111                         int32_t const frames_to_mix = frames(overlap->duration());
 112                         if (i.time < time) {
 113                                 i.audio->accumulate_frames(audio.get(), frames_to_mix, 0, offset);
 114                         } else {
 115                                 i.audio->accumulate_frames(audio.get(), frames_to_mix, offset, 0);
 116                         }
 117                 }
 118         }
 119
 120         list<DCPTimePeriod> periods;
 121         BOOST_FOREACH (Buffer i, _buffers) {
 122                 periods.push_back (i.period ());
 123         }
 124
 125         /* Add the non-overlapping parts */
 126         BOOST_FOREACH (DCPTimePeriod i, subtract (period, periods)) {
 127                 list<Buffer>::iterator before = _buffers.end();
 128                 list<Buffer>::iterator after = _buffers.end();
 129                 for (list<Buffer>::iterator j = _buffers.begin(); j != _buffers.end(); ++j) {
 130                         if (j->period().to == i.from) {
 131                                 before = j;
 132                         }
 133                         if (j->period().from == i.to) {
 134                                 after = j;
 135                         }
 136                 }
 137
 138                 /* Get the part of audio that we want to use */
 139                 shared_ptr<AudioBuffers> part (new AudioBuffers (audio->channels(), frames(i.to) - frames(i.from)));
 140                 part->copy_from (audio.get(), part->frames(), frames(DCPTime(i.from - time)), 0);
 141
 142                 if (before == _buffers.end() && after == _buffers.end()) {
 143                         /* New buffer */
 144                         DCPOMATIC_ASSERT (part->frames() > 0);
 145                         _buffers.push_back (Buffer (part, time, _frame_rate));
 146                 } else if (before != _buffers.end() && after == _buffers.end()) {
 147                         /* We have an existing buffer before this one; append new data to it */
 148                         before->audio->append (part);
 149                 } else if (before ==_buffers.end() && after != _buffers.end()) {
 150                         /* We have an existing buffer after this one; append it to the new data and replace */
 151                         part->append (after->audio);
 152                         after->audio = part;
 153                         after->time = time;
 154                 } else {
 155                         /* We have existing buffers both before and after; coalesce them all */
 156                         before->audio->append (part);
 157                         before->audio->append (after->audio);
 158                         _buffers.erase (after);
 159                 }
 160         }
 161 }
 162
 163 void
 164 AudioMerger::clear ()
 165 {
 166         _buffers.clear ();
 167         _last_pull = DCPTime ();
 168 }