src/lib/audio_ring_buffers.cc

   1 /*
   2     Copyright (C) 2016-2018 Carl Hetherington <cth@carlh.net>
   3
   4     This file is part of DCP-o-matic.
   5
   6     DCP-o-matic is free software; you can redistribute it and/or modify
   7     it under the terms of the GNU General Public License as published by
   8     the Free Software Foundation; either version 2 of the License, or
   9     (at your option) any later version.
  10
  11     DCP-o-matic is distributed in the hope that it will be useful,
  12     but WITHOUT ANY WARRANTY; without even the implied warranty of
  13     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14     GNU General Public License for more details.
  15
  16     You should have received a copy of the GNU General Public License
  17     along with DCP-o-matic.  If not, see <http://www.gnu.org/licenses/>.
  18
  19 */
  20
  21 #include "audio_ring_buffers.h"
  22 #include "dcpomatic_assert.h"
  23 #include "exceptions.h"
  24 #include <boost/foreach.hpp>
  25 #include <iostream>
  26
  27 using std::min;
  28 using std::cout;
  29 using std::make_pair;
  30 using std::pair;
  31 using std::list;
  32 using boost::shared_ptr;
  33 using boost::optional;
  34
  35 AudioRingBuffers::AudioRingBuffers ()
  36         : _used_in_head (0)
  37 {
  38
  39 }
  40
  41 void
  42 AudioRingBuffers::put (shared_ptr<const AudioBuffers> data, DCPTime time)
  43 {
  44         boost::mutex::scoped_lock lm (_mutex);
  45
  46         if (!_buffers.empty()) {
  47                 DCPOMATIC_ASSERT (_buffers.front().first->channels() == data->channels());
  48                 DCPOMATIC_ASSERT ((_buffers.back().second + DCPTime::from_frames(_buffers.back().first->frames(), 48000)) == time);
  49         }
  50
  51         _buffers.push_back(make_pair(data, time));
  52 }
  53
  54 /** @return time of the returned data; if it's not set this indicates an underrun */
  55 optional<DCPTime>
  56 AudioRingBuffers::get (float* out, int channels, int frames)
  57 {
  58         boost::mutex::scoped_lock lm (_mutex);
  59
  60         optional<DCPTime> time;
  61
  62         while (frames > 0) {
  63                 if (_buffers.empty ()) {
  64                         for (int i = 0; i < frames; ++i) {
  65                                 for (int j = 0; j < channels; ++j) {
  66                                         *out++ = 0;
  67                                 }
  68                         }
  69                         cout << "audio underrun; missing " << frames << "!\n";
  70                         return time;
  71                 }
  72
  73                 pair<shared_ptr<const AudioBuffers>, DCPTime> front = _buffers.front ();
  74                 if (!time) {
  75                         time = front.second + DCPTime::from_frames(_used_in_head, 48000);
  76                 }
  77
  78                 int const to_do = min (frames, front.first->frames() - _used_in_head);
  79                 float** p = front.first->data();
  80                 int const c = min (front.first->channels(), channels);
  81                 for (int i = 0; i < to_do; ++i) {
  82                         for (int j = 0; j < c; ++j) {
  83                                 *out++ = p[j][i + _used_in_head];
  84                         }
  85                         for (int j = c; j < channels; ++j) {
  86                                 *out++ = 0;
  87                         }
  88                 }
  89                 _used_in_head += to_do;
  90                 frames -= to_do;
  91
  92                 if (_used_in_head == front.first->frames()) {
  93                         _buffers.pop_front ();
  94                         _used_in_head = 0;
  95                 }
  96         }
  97
  98         return time;
  99 }
 100
 101 void
 102 AudioRingBuffers::clear ()
 103 {
 104         boost::mutex::scoped_lock lm (_mutex);
 105         _buffers.clear ();
 106         _used_in_head = 0;
 107 }
 108
 109 Frame
 110 AudioRingBuffers::size () const
 111 {
 112         boost::mutex::scoped_lock lm (_mutex);
 113         Frame s = 0;
 114         for (list<pair<shared_ptr<const AudioBuffers>, DCPTime> >::const_iterator i = _buffers.begin(); i != _buffers.end(); ++i) {
 115                 s += i->first->frames();
 116         }
 117         return s - _used_in_head;
 118 }