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                 if ((_buffers.back().second + DCPTime::from_frames(_buffers.back().first->frames(), 48000)) != time) {
  49                         cout << "bad put " << to_string(_buffers.back().second) << " " << _buffers.back().first->frames() << " " << to_string(time) << "\n";
  50                 }
  51                 DCPOMATIC_ASSERT ((_buffers.back().second + DCPTime::from_frames(_buffers.back().first->frames(), 48000)) == time);
  52         }
  53
  54         _buffers.push_back(make_pair(data, time));
  55 }
  56
  57 /** @return time of the returned data; if it's not set this indicates an underrun */
  58 optional<DCPTime>
  59 AudioRingBuffers::get (float* out, int channels, int frames)
  60 {
  61         boost::mutex::scoped_lock lm (_mutex);
  62
  63         optional<DCPTime> time;
  64
  65         while (frames > 0) {
  66                 if (_buffers.empty ()) {
  67                         for (int i = 0; i < frames; ++i) {
  68                                 for (int j = 0; j < channels; ++j) {
  69                                         *out++ = 0;
  70                                 }
  71                         }
  72                         cout << "audio underrun; missing " << frames << "!\n";
  73                         return time;
  74                 }
  75
  76                 pair<shared_ptr<const AudioBuffers>, DCPTime> front = _buffers.front ();
  77                 if (!time) {
  78                         time = front.second + DCPTime::from_frames(_used_in_head, 48000);
  79                 }
  80
  81                 int const to_do = min (frames, front.first->frames() - _used_in_head);
  82                 float** p = front.first->data();
  83                 int const c = min (front.first->channels(), channels);
  84                 for (int i = 0; i < to_do; ++i) {
  85                         for (int j = 0; j < c; ++j) {
  86                                 *out++ = p[j][i + _used_in_head];
  87                         }
  88                         for (int j = c; j < channels; ++j) {
  89                                 *out++ = 0;
  90                         }
  91                 }
  92                 _used_in_head += to_do;
  93                 frames -= to_do;
  94
  95                 if (_used_in_head == front.first->frames()) {
  96                         _buffers.pop_front ();
  97                         _used_in_head = 0;
  98                 }
  99         }
 100
 101         return time;
 102 }
 103
 104 void
 105 AudioRingBuffers::clear ()
 106 {
 107         boost::mutex::scoped_lock lm (_mutex);
 108         _buffers.clear ();
 109         _used_in_head = 0;
 110 }
 111
 112 Frame
 113 AudioRingBuffers::size () const
 114 {
 115         boost::mutex::scoped_lock lm (_mutex);
 116         Frame s = 0;
 117         for (list<pair<shared_ptr<const AudioBuffers>, DCPTime> >::const_iterator i = _buffers.begin(); i != _buffers.end(); ++i) {
 118                 s += i->first->frames();
 119         }
 120         return s - _used_in_head;
 121 }