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 #include "audio_merger.h"
  21 #include "dcpomatic_time.h"
  22 #include <iostream>
  23
  24 using std::pair;
  25 using std::min;
  26 using std::max;
  27 using std::list;
  28 using std::cout;
  29 using std::make_pair;
  30 using boost::shared_ptr;
  31 using boost::optional;
  32
  33 AudioMerger::AudioMerger (int frame_rate)
  34         : _last_pull (0)
  35         , _frame_rate (frame_rate)
  36 {
  37
  38 }
  39
  40 /** Pull audio up to a given time; after this call, no more data can be pushed
  41  *  before the specified time.
  42  */
  43 list<pair<shared_ptr<AudioBuffers>, DCPTime> >
  44 AudioMerger::pull (DCPTime time)
  45 {
  46         list<pair<shared_ptr<AudioBuffers>, DCPTime> > out;
  47
  48         DCPTimePeriod period (_last_pull, time);
  49         _buffers.sort (AudioMerger::BufferComparator());
  50
  51         list<Buffer> new_buffers;
  52
  53         BOOST_FOREACH (Buffer i, _buffers) {
  54                 if (i.period().to < time) {
  55                         /* Completely within the pull period */
  56                         out.push_back (make_pair (i.audio, i.time));
  57                 } else if (i.time < time) {
  58                         /* Overlaps the end of the pull period */
  59                         shared_ptr<AudioBuffers> audio (new AudioBuffers (i.audio->channels(), DCPTime(time - i.time).frames_floor(_frame_rate)));
  60                         audio->copy_from (i.audio.get(), audio->frames(), 0, 0);
  61                         out.push_back (make_pair (audio, i.time));
  62                         i.audio->trim_start (audio->frames ());
  63                         i.time += DCPTime::from_frames(audio->frames(), _frame_rate);
  64                         new_buffers.push_back (i);
  65                 } else {
  66                         /* Not involved */
  67                         new_buffers.push_back (i);
  68                 }
  69         }
  70
  71         _buffers = new_buffers;
  72         return out;
  73 }
  74
  75 void
  76 AudioMerger::push (boost::shared_ptr<const AudioBuffers> audio, DCPTime time)
  77 {
  78         DCPOMATIC_ASSERT (time >= _last_pull);
  79
  80         DCPTimePeriod period (time, time + DCPTime::from_frames (audio->frames(), _frame_rate));
  81
  82         /* Mix any parts of this new block with existing ones */
  83         BOOST_FOREACH (Buffer i, _buffers) {
  84                 optional<DCPTimePeriod> overlap = i.period().overlap (period);
  85                 if (overlap) {
  86                         int32_t const offset = DCPTime(overlap->from - i.time).frames_floor(_frame_rate);
  87                         int32_t const frames = overlap->duration().frames_floor(_frame_rate);
  88                         if (i.time < time) {
  89                                 i.audio->accumulate_frames(audio.get(), frames, 0, offset);
  90                         } else {
  91                                 i.audio->accumulate_frames(audio.get(), frames, offset, 0);
  92                         }
  93                 }
  94         }
  95
  96         list<DCPTimePeriod> periods;
  97         BOOST_FOREACH (Buffer i, _buffers) {
  98                 periods.push_back (i.period ());
  99         }
 100
 101         /* Add the non-overlapping parts */
 102         BOOST_FOREACH (DCPTimePeriod i, subtract (period, periods)) {
 103                 list<Buffer>::iterator before = _buffers.end();
 104                 list<Buffer>::iterator after = _buffers.end();
 105                 for (list<Buffer>::iterator j = _buffers.begin(); j != _buffers.end(); ++j) {
 106                         if (j->period().to == i.from) {
 107                                 before = j;
 108                         }
 109                         if (j->period().from == i.to) {
 110                                 after = j;
 111                         }
 112                 }
 113
 114                 /* Get the part of audio that we want to use */
 115                 shared_ptr<AudioBuffers> part (new AudioBuffers (audio->channels(), i.to.frames_floor(_frame_rate) - i.from.frames_floor(_frame_rate)));
 116                 part->copy_from (audio.get(), part->frames(), DCPTime(i.from - time).frames_floor(_frame_rate), 0);
 117
 118                 if (before == _buffers.end() && after == _buffers.end()) {
 119                         /* New buffer */
 120                         _buffers.push_back (Buffer (part, time, _frame_rate));
 121                 } else if (before != _buffers.end() && after == _buffers.end()) {
 122                         /* We have an existing buffer before this one; append new data to it */
 123                         before->audio->append (part);
 124                 } else if (before ==_buffers.end() && after != _buffers.end()) {
 125                         /* We have an existing buffer after this one; append it to the new data and replace */
 126                         part->append (after->audio);
 127                         after->audio = part;
 128                         after->time = time;
 129                 } else {
 130                         /* We have existing buffers both before and after; coalesce them all */
 131                         before->audio->append (part);
 132                         before->audio->append (after->audio);
 133                         _buffers.erase (after);
 134                 }
 135         }
 136 }