src/lib/audio_ring_buffers.cc

   1 /*
   2     Copyright (C) 2016-2019 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 using namespace dcpomatic;
  35
  36 AudioRingBuffers::AudioRingBuffers ()
  37         : _used_in_head (0)
  38 {
  39
  40 }
  41
  42 /** @param frame_rate Frame rate in use; this is only used to check timing consistency of the incoming data */
  43 void
  44 AudioRingBuffers::put (shared_ptr<const AudioBuffers> data, DCPTime time, int frame_rate)
  45 {
  46         boost::mutex::scoped_lock lm (_mutex);
  47
  48         if (!_buffers.empty()) {
  49                 DCPOMATIC_ASSERT (_buffers.front().first->channels() == data->channels());
  50                 DCPTime const end = (_buffers.back().second + DCPTime::from_frames(_buffers.back().first->frames(), frame_rate));
  51                 if (labs(end.get() - time.get()) > 1) {
  52                         cout << "bad put " << to_string(_buffers.back().second) << " " << _buffers.back().first->frames() << " " << to_string(time) << "\n";
  53                 }
  54                 DCPOMATIC_ASSERT (labs(end.get() - time.get()) < 2);
  55         }
  56
  57         _buffers.push_back(make_pair(data, time));
  58 }
  59
  60 /** @return time of the returned data; if it's not set this indicates an underrun */
  61 optional<DCPTime>
  62 AudioRingBuffers::get (float* out, int channels, int frames)
  63 {
  64         boost::mutex::scoped_lock lm (_mutex);
  65
  66         optional<DCPTime> time;
  67
  68         while (frames > 0) {
  69                 if (_buffers.empty ()) {
  70                         for (int i = 0; i < frames; ++i) {
  71                                 for (int j = 0; j < channels; ++j) {
  72                                         *out++ = 0;
  73                                 }
  74                         }
  75                         cout << "audio underrun; missing " << frames << "!\n";
  76                         return time;
  77                 }
  78
  79                 pair<shared_ptr<const AudioBuffers>, DCPTime> front = _buffers.front ();
  80                 if (!time) {
  81                         time = front.second + DCPTime::from_frames(_used_in_head, 48000);
  82                 }
  83
  84                 int const to_do = min (frames, front.first->frames() - _used_in_head);
  85                 float** p = front.first->data();
  86                 int const c = min (front.first->channels(), channels);
  87                 for (int i = 0; i < to_do; ++i) {
  88                         for (int j = 0; j < c; ++j) {
  89                                 *out++ = p[j][i + _used_in_head];
  90                         }
  91                         for (int j = c; j < channels; ++j) {
  92                                 *out++ = 0;
  93                         }
  94                 }
  95                 _used_in_head += to_do;
  96                 frames -= to_do;
  97
  98                 if (_used_in_head == front.first->frames()) {
  99                         _buffers.pop_front ();
 100                         _used_in_head = 0;
 101                 }
 102         }
 103
 104         return time;
 105 }
 106
 107 optional<DCPTime>
 108 AudioRingBuffers::peek () const
 109 {
 110         boost::mutex::scoped_lock lm (_mutex);
 111         if (_buffers.empty()) {
 112                 return optional<DCPTime>();
 113         }
 114         return _buffers.front().second;
 115 }
 116
 117 void
 118 AudioRingBuffers::clear ()
 119 {
 120         boost::mutex::scoped_lock lm (_mutex);
 121         _buffers.clear ();
 122         _used_in_head = 0;
 123 }
 124
 125 Frame
 126 AudioRingBuffers::size () const
 127 {
 128         boost::mutex::scoped_lock lm (_mutex);
 129         Frame s = 0;
 130         for (list<pair<shared_ptr<const AudioBuffers>, DCPTime> >::const_iterator i = _buffers.begin(); i != _buffers.end(); ++i) {
 131                 s += i->first->frames();
 132         }
 133         return s - _used_in_head;
 134 }