src/lib/butler.cc

   1 /*
   2     Copyright (C) 2016-2017 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 "butler.h"
  22 #include "player.h"
  23 #include <boost/weak_ptr.hpp>
  24 #include <boost/shared_ptr.hpp>
  25
  26 using std::cout;
  27 using std::pair;
  28 using std::make_pair;
  29 using boost::weak_ptr;
  30 using boost::shared_ptr;
  31 using boost::bind;
  32 using boost::optional;
  33
  34 /** Video readahead in frames */
  35 #define VIDEO_READAHEAD 10
  36 /** Audio readahead in frames */
  37 #define AUDIO_READAHEAD (48000*5)
  38
  39 Butler::Butler (weak_ptr<const Film> film, shared_ptr<Player> player, AudioMapping audio_mapping, int audio_channels)
  40         : _film (film)
  41         , _player (player)
  42         , _pending_seek_accurate (false)
  43         , _finished (false)
  44         , _died (false)
  45         , _stop_thread (false)
  46         , _audio_mapping (audio_mapping)
  47         , _audio_channels (audio_channels)
  48         , _disable_audio (false)
  49 {
  50         _player_video_connection = _player->Video.connect (bind (&Butler::video, this, _1, _2));
  51         _player_audio_connection = _player->Audio.connect (bind (&Butler::audio, this, _1, _2));
  52         _player_changed_connection = _player->Changed.connect (bind (&Butler::player_changed, this));
  53         _thread = new boost::thread (bind (&Butler::thread, this));
  54 }
  55
  56 Butler::~Butler ()
  57 {
  58         {
  59                 boost::mutex::scoped_lock lm (_mutex);
  60                 _stop_thread = true;
  61         }
  62
  63         _thread->interrupt ();
  64         try {
  65                 _thread->join ();
  66         } catch (boost::thread_interrupted& e) {
  67                 /* No problem */
  68         }
  69         delete _thread;
  70 }
  71
  72 /** Caller must hold a lock on _mutex */
  73 bool
  74 Butler::should_run () const
  75 {
  76         return (_video.size() < VIDEO_READAHEAD || (!_disable_audio && _audio.size() < AUDIO_READAHEAD)) && !_stop_thread && !_finished && !_died;
  77 }
  78
  79 void
  80 Butler::thread ()
  81 try
  82 {
  83         while (true) {
  84                 boost::mutex::scoped_lock lm (_mutex);
  85
  86                 /* Wait until we have something to do */
  87                 while (!should_run() && !_pending_seek_position) {
  88                         _summon.wait (lm);
  89                 }
  90
  91                 /* Do any seek that has been requested */
  92                 if (_pending_seek_position) {
  93                         _video.clear ();
  94                         _audio.clear ();
  95                         _finished = false;
  96                         _player->seek (*_pending_seek_position, _pending_seek_accurate);
  97                         _pending_seek_position = optional<DCPTime> ();
  98                 }
  99
 100                 /* Fill _video and _audio.  Don't try to carry on if a pending seek appears
 101                    while lm is unlocked, as in that state nothing will be added to
 102                    _video/_audio.
 103                 */
 104                 while (should_run() && !_pending_seek_position) {
 105                         lm.unlock ();
 106                         bool const r = _player->pass ();
 107                         lm.lock ();
 108                         if (r) {
 109                                 _finished = true;
 110                                 _arrived.notify_all ();
 111                                 break;
 112                         }
 113                         _arrived.notify_all ();
 114                 }
 115         }
 116 } catch (boost::thread_interrupted) {
 117         /* The butler thread is being terminated */
 118         boost::mutex::scoped_lock lm (_mutex);
 119         _finished = true;
 120         _arrived.notify_all ();
 121 } catch (...) {
 122         store_current ();
 123         boost::mutex::scoped_lock lm (_mutex);
 124         _died = true;
 125         _arrived.notify_all ();
 126 }
 127
 128 pair<shared_ptr<PlayerVideo>, DCPTime>
 129 Butler::get_video ()
 130 {
 131         boost::mutex::scoped_lock lm (_mutex);
 132
 133         /* Wait for data if we have none */
 134         while (_video.empty() && !_finished && !_died) {
 135                 _arrived.wait (lm);
 136         }
 137
 138         if (_video.empty()) {
 139                 return make_pair (shared_ptr<PlayerVideo>(), DCPTime());
 140         }
 141
 142         pair<shared_ptr<PlayerVideo>, DCPTime> const r = _video.get ();
 143         _summon.notify_all ();
 144         return r;
 145 }
 146
 147 void
 148 Butler::seek (DCPTime position, bool accurate)
 149 {
 150         boost::mutex::scoped_lock lm (_mutex);
 151         if (_died) {
 152                 return;
 153         }
 154
 155         _pending_seek_position = position;
 156         _pending_seek_accurate = accurate;
 157         _summon.notify_all ();
 158 }
 159
 160 void
 161 Butler::video (shared_ptr<PlayerVideo> video, DCPTime time)
 162 {
 163         {
 164                 boost::mutex::scoped_lock lm (_mutex);
 165                 if (_pending_seek_position) {
 166                         /* Don't store any video while a seek is pending */
 167                         return;
 168                 }
 169         }
 170
 171         _video.put (video, time);
 172 }
 173
 174 void
 175 Butler::audio (shared_ptr<AudioBuffers> audio, DCPTime time)
 176 {
 177         {
 178                 boost::mutex::scoped_lock lm (_mutex);
 179                 if (_pending_seek_position || _disable_audio) {
 180                         /* Don't store any audio while a seek is pending, or if audio is disabled */
 181                         return;
 182                 }
 183         }
 184
 185         _audio.put (audio, time);
 186 }
 187
 188 void
 189 Butler::player_changed ()
 190 {
 191         optional<DCPTime> t;
 192
 193         {
 194                 boost::mutex::scoped_lock lm (_mutex);
 195                 t = _video.earliest ();
 196         }
 197
 198         if (t) {
 199                 seek (*t, true);
 200         } else {
 201                 _video.clear ();
 202                 _audio.clear ();
 203         }
 204 }
 205
 206 void
 207 Butler::get_audio (float* out, Frame frames)
 208 {
 209         _audio.get (out, _audio_channels, frames);
 210         _summon.notify_all ();
 211 }
 212
 213 void
 214 Butler::disable_audio ()
 215 {
 216         boost::mutex::scoped_lock lm (_mutex);
 217         _disable_audio = true;
 218 }