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 <iostream>
  25
  26 using std::min;
  27 using std::cout;
  28 using std::make_pair;
  29 using std::pair;
  30 using std::list;
  31 using std::shared_ptr;
  32 using boost::optional;
  33 using namespace dcpomatic;
  34
  35 AudioRingBuffers::AudioRingBuffers ()
  36         : _used_in_head (0)
  37 {
  38
  39 }
  40
  41 /** @param frame_rate Frame rate in use; this is only used to check timing consistency of the incoming data */
  42 void
  43 AudioRingBuffers::put (shared_ptr<const AudioBuffers> data, DCPTime time, int frame_rate)
  44 {
  45         boost::mutex::scoped_lock lm (_mutex);
  46
  47         if (!_buffers.empty()) {
  48                 DCPOMATIC_ASSERT (_buffers.front().first->channels() == data->channels());
  49                 DCPTime const end = (_buffers.back().second + DCPTime::from_frames(_buffers.back().first->frames(), frame_rate));
  50                 if (labs(end.get() - time.get()) > 1) {
  51                         cout << "bad put " << to_string(_buffers.back().second) << " " << _buffers.back().first->frames() << " " << to_string(time) << "\n";
  52                 }
  53                 DCPOMATIC_ASSERT (labs(end.get() - time.get()) < 2);
  54         }
  55
  56         _buffers.push_back(make_pair(data, time));
  57 }
  58
  59 /** @return time of the returned data; if it's not set this indicates an underrun */
  60 optional<DCPTime>
  61 AudioRingBuffers::get (float* out, int channels, int frames)
  62 {
  63         boost::mutex::scoped_lock lm (_mutex);
  64
  65         optional<DCPTime> time;
  66
  67         while (frames > 0) {
  68                 if (_buffers.empty ()) {
  69                         for (int i = 0; i < frames; ++i) {
  70                                 for (int j = 0; j < channels; ++j) {
  71                                         *out++ = 0;
  72                                 }
  73                         }
  74                         cout << "audio underrun; missing " << frames << "!\n";
  75                         return time;
  76                 }
  77
  78                 pair<shared_ptr<const AudioBuffers>, DCPTime> front = _buffers.front ();
  79                 if (!time) {
  80                         time = front.second + DCPTime::from_frames(_used_in_head, 48000);
  81                 }
  82
  83                 int const to_do = min (frames, front.first->frames() - _used_in_head);
  84                 float** p = front.first->data();
  85                 int const c = min (front.first->channels(), channels);
  86                 for (int i = 0; i < to_do; ++i) {
  87                         for (int j = 0; j < c; ++j) {
  88                                 *out++ = p[j][i + _used_in_head];
  89                         }
  90                         for (int j = c; j < channels; ++j) {
  91                                 *out++ = 0;
  92                         }
  93                 }
  94                 _used_in_head += to_do;
  95                 frames -= to_do;
  96
  97                 if (_used_in_head == front.first->frames()) {
  98                         _buffers.pop_front ();
  99                         _used_in_head = 0;
 100                 }
 101         }
 102
 103         return time;
 104 }
 105
 106 optional<DCPTime>
 107 AudioRingBuffers::peek () const
 108 {
 109         boost::mutex::scoped_lock lm (_mutex);
 110         if (_buffers.empty()) {
 111                 return optional<DCPTime>();
 112         }
 113         return _buffers.front().second;
 114 }
 115
 116 void
 117 AudioRingBuffers::clear ()
 118 {
 119         boost::mutex::scoped_lock lm (_mutex);
 120         _buffers.clear ();
 121         _used_in_head = 0;
 122 }
 123
 124 Frame
 125 AudioRingBuffers::size () const
 126 {
 127         boost::mutex::scoped_lock lm (_mutex);
 128         Frame s = 0;
 129         for (list<pair<shared_ptr<const AudioBuffers>, DCPTime> >::const_iterator i = _buffers.begin(); i != _buffers.end(); ++i) {
 130                 s += i->first->frames();
 131         }
 132         return s - _used_in_head;
 133 }