src/lib/audio_ring_buffers.cc

   1 /*
   2     Copyright (C) 2016-2021 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
  22 #include "audio_ring_buffers.h"
  23 #include "dcpomatic_assert.h"
  24 #include "exceptions.h"
  25 #include <iostream>
  26
  27
  28 using std::min;
  29 using std::cout;
  30 using std::make_pair;
  31 using std::pair;
  32 using std::list;
  33 using std::shared_ptr;
  34 using boost::optional;
  35 using namespace dcpomatic;
  36
  37
  38 AudioRingBuffers::AudioRingBuffers ()
  39 {
  40
  41 }
  42
  43
  44 /** @param frame_rate Frame rate in use; this is only used to check timing consistency of the incoming data */
  45 void
  46 AudioRingBuffers::put (shared_ptr<const AudioBuffers> data, DCPTime time, int frame_rate)
  47 {
  48         boost::mutex::scoped_lock lm (_mutex);
  49
  50         if (!_buffers.empty()) {
  51                 DCPOMATIC_ASSERT (_buffers.front().first->channels() == data->channels());
  52                 DCPTime const end = (_buffers.back().second + DCPTime::from_frames(_buffers.back().first->frames(), frame_rate));
  53                 if (labs(end.get() - time.get()) > 1) {
  54                         cout << "bad put " << to_string(_buffers.back().second) << " " << _buffers.back().first->frames() << " " << to_string(time) << "\n";
  55                 }
  56                 DCPOMATIC_ASSERT (labs(end.get() - time.get()) < 2);
  57         }
  58
  59         _buffers.push_back(make_pair(data, time));
  60 }
  61
  62
  63 /** @return time of the returned data; if it's not set this indicates an underrun */
  64 optional<DCPTime>
  65 AudioRingBuffers::get (float* out, int channels, int frames)
  66 {
  67         boost::mutex::scoped_lock lm (_mutex);
  68
  69         optional<DCPTime> time;
  70
  71         while (frames > 0) {
  72                 if (_buffers.empty ()) {
  73                         for (int i = 0; i < frames; ++i) {
  74                                 for (int j = 0; j < channels; ++j) {
  75                                         *out++ = 0;
  76                                 }
  77                         }
  78                         cout << "audio underrun; missing " << frames << "!\n";
  79                         return time;
  80                 }
  81
  82                 auto front = _buffers.front ();
  83                 if (!time) {
  84                         time = front.second + DCPTime::from_frames(_used_in_head, 48000);
  85                 }
  86
  87                 int const to_do = min (frames, front.first->frames() - _used_in_head);
  88                 float** p = front.first->data();
  89                 int const c = min (front.first->channels(), channels);
  90                 for (int i = 0; i < to_do; ++i) {
  91                         for (int j = 0; j < c; ++j) {
  92                                 *out++ = p[j][i + _used_in_head];
  93                         }
  94                         for (int j = c; j < channels; ++j) {
  95                                 *out++ = 0;
  96                         }
  97                 }
  98                 _used_in_head += to_do;
  99                 frames -= to_do;
 100
 101                 if (_used_in_head == front.first->frames()) {
 102                         _buffers.pop_front ();
 103                         _used_in_head = 0;
 104                 }
 105         }
 106
 107         return time;
 108 }
 109
 110
 111 optional<DCPTime>
 112 AudioRingBuffers::peek () const
 113 {
 114         boost::mutex::scoped_lock lm (_mutex);
 115         if (_buffers.empty()) {
 116                 return {};
 117         }
 118         return _buffers.front().second;
 119 }
 120
 121
 122 void
 123 AudioRingBuffers::clear ()
 124 {
 125         boost::mutex::scoped_lock lm (_mutex);
 126         _buffers.clear ();
 127         _used_in_head = 0;
 128 }
 129
 130
 131 Frame
 132 AudioRingBuffers::size () const
 133 {
 134         boost::mutex::scoped_lock lm (_mutex);
 135         Frame s = 0;
 136         for (auto const& i: _buffers) {
 137                 s += i.first->frames();
 138         }
 139         return s - _used_in_head;
 140 }