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         list<Buffer> new_buffers;
  60
  61         _buffers.sort (AudioMerger::BufferComparator());
  62         BOOST_FOREACH (Buffer i, _buffers) {
  63                 if (i.period().to <= time) {
  64                         /* Completely within the pull period */
  65                         DCPOMATIC_ASSERT (i.audio->frames() > 0);
  66                         out.push_back (make_pair (i.audio, i.time));
  67                 } else if (i.time < time) {
  68                         /* Overlaps the end of the pull period */
  69                         shared_ptr<AudioBuffers> audio (new AudioBuffers (i.audio->channels(), frames(DCPTime(time - i.time))));
  70                         /* Though time > i.time, audio->frames() could be 0 if the difference in time is less than one frame */
  71                         if (audio->frames() > 0) {
  72                                 audio->copy_from (i.audio.get(), audio->frames(), 0, 0);
  73                                 out.push_back (make_pair (audio, i.time));
  74                                 i.audio->trim_start (audio->frames ());
  75                                 i.time += DCPTime::from_frames(audio->frames(), _frame_rate);
  76                                 DCPOMATIC_ASSERT (i.audio->frames() > 0);
  77                                 new_buffers.push_back (i);
  78                         }
  79                 } else {
  80                         /* Not involved */
  81                         DCPOMATIC_ASSERT (i.audio->frames() > 0);
  82                         new_buffers.push_back (i);
  83                 }
  84         }
  85
  86         _buffers = new_buffers;
  87
  88         for (list<pair<shared_ptr<AudioBuffers>, DCPTime> >::const_iterator i = out.begin(); i != out.end(); ++i) {
  89                 DCPOMATIC_ASSERT (i->first->frames() > 0);
  90         }
  91
  92         return out;
  93 }
  94
  95 /** Push some data into the merger at a given time */
  96 void
  97 AudioMerger::push (boost::shared_ptr<const AudioBuffers> audio, DCPTime time)
  98 {
  99         DCPOMATIC_ASSERT (audio->frames() > 0);
 100
 101         DCPTimePeriod period (time, time + DCPTime::from_frames (audio->frames(), _frame_rate));
 102
 103         /* Mix any overlapping parts of this new block with existing ones */
 104         BOOST_FOREACH (Buffer i, _buffers) {
 105                 optional<DCPTimePeriod> overlap = i.period().overlap (period);
 106                 if (overlap) {
 107                         int32_t const offset = frames(DCPTime(overlap->from - i.time));
 108                         int32_t const frames_to_mix = frames(overlap->duration());
 109                         if (i.time < time) {
 110                                 i.audio->accumulate_frames(audio.get(), frames_to_mix, 0, offset);
 111                         } else {
 112                                 i.audio->accumulate_frames(audio.get(), frames_to_mix, offset, 0);
 113                         }
 114                 }
 115         }
 116
 117         list<DCPTimePeriod> periods;
 118         BOOST_FOREACH (Buffer i, _buffers) {
 119                 periods.push_back (i.period ());
 120         }
 121
 122         /* Add the non-overlapping parts */
 123         BOOST_FOREACH (DCPTimePeriod i, subtract (period, periods)) {
 124                 list<Buffer>::iterator before = _buffers.end();
 125                 list<Buffer>::iterator after = _buffers.end();
 126                 for (list<Buffer>::iterator j = _buffers.begin(); j != _buffers.end(); ++j) {
 127                         if (j->period().to == i.from) {
 128                                 before = j;
 129                         }
 130                         if (j->period().from == i.to) {
 131                                 after = j;
 132                         }
 133                 }
 134
 135                 /* Get the part of audio that we want to use */
 136                 shared_ptr<AudioBuffers> part (new AudioBuffers (audio->channels(), frames(i.to) - frames(i.from)));
 137                 part->copy_from (audio.get(), part->frames(), frames(DCPTime(i.from - time)), 0);
 138
 139                 if (before == _buffers.end() && after == _buffers.end()) {
 140                         /* New buffer */
 141                         DCPOMATIC_ASSERT (part->frames() > 0);
 142                         _buffers.push_back (Buffer (part, time, _frame_rate));
 143                 } else if (before != _buffers.end() && after == _buffers.end()) {
 144                         /* We have an existing buffer before this one; append new data to it */
 145                         before->audio->append (part);
 146                 } else if (before ==_buffers.end() && after != _buffers.end()) {
 147                         /* We have an existing buffer after this one; append it to the new data and replace */
 148                         part->append (after->audio);
 149                         after->audio = part;
 150                         after->time = time;
 151                 } else {
 152                         /* We have existing buffers both before and after; coalesce them all */
 153                         before->audio->append (part);
 154                         before->audio->append (after->audio);
 155                         _buffers.erase (after);
 156                 }
 157         }
 158 }
 159
 160 void
 161 AudioMerger::clear ()
 162 {
 163         _buffers.clear ();
 164 }