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         , _audio_mapping (audio_mapping)
  46         , _audio_channels (audio_channels)
  47         , _stop_thread (false)
  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         _stop_thread = true;
  59         _thread->interrupt ();
  60         try {
  61                 _thread->join ();
  62         } catch (boost::thread_interrupted& e) {
  63                 /* No problem */
  64         }
  65         delete _thread;
  66 }
  67
  68 bool
  69 Butler::should_run () const
  70 {
  71         return (_video.size() < VIDEO_READAHEAD || (!_disable_audio && _audio.size() < AUDIO_READAHEAD)) && !_stop_thread && !_finished && !_died;
  72 }
  73
  74 void
  75 Butler::thread ()
  76 try
  77 {
  78         while (true) {
  79                 boost::mutex::scoped_lock lm (_mutex);
  80
  81                 /* Wait until we have something to do */
  82                 while (!should_run() && !_pending_seek_position) {
  83                         _summon.wait (lm);
  84                 }
  85
  86                 /* Do any seek that has been requested */
  87                 if (_pending_seek_position) {
  88                         _player->seek (*_pending_seek_position, _pending_seek_accurate);
  89                         _pending_seek_position = optional<DCPTime> ();
  90                 }
  91
  92                 /* Fill _video and _audio.  Don't try to carry on if a pending seek appears
  93                    while lm is unlocked, as in that state nothing will be added to
  94                    _video/_audio.
  95                 */
  96                 while (should_run() && !_pending_seek_position) {
  97                         lm.unlock ();
  98                         bool const r = _player->pass ();
  99                         lm.lock ();
 100                         if (r) {
 101                                 _finished = true;
 102                                 _arrived.notify_all ();
 103                                 break;
 104                         }
 105                         _arrived.notify_all ();
 106                 }
 107         }
 108 } catch (boost::thread_interrupted) {
 109         /* The butler thread is being terminated */
 110         boost::mutex::scoped_lock lm (_mutex);
 111         _finished = true;
 112         _arrived.notify_all ();
 113 } catch (...) {
 114         store_current ();
 115         boost::mutex::scoped_lock lm (_mutex);
 116         _died = true;
 117         _arrived.notify_all ();
 118 }
 119
 120 pair<shared_ptr<PlayerVideo>, DCPTime>
 121 Butler::get_video ()
 122 {
 123         boost::mutex::scoped_lock lm (_mutex);
 124
 125         /* Wait for data if we have none */
 126         while (_video.empty() && !_finished && !_died) {
 127                 _arrived.wait (lm);
 128         }
 129
 130         if (_video.empty()) {
 131                 return make_pair (shared_ptr<PlayerVideo>(), DCPTime());
 132         }
 133
 134         pair<shared_ptr<PlayerVideo>, DCPTime> const r = _video.get ();
 135         _summon.notify_all ();
 136         return r;
 137 }
 138
 139 void
 140 Butler::seek (DCPTime position, bool accurate)
 141 {
 142         boost::mutex::scoped_lock lm (_mutex);
 143         if (_died) {
 144                 return;
 145         }
 146
 147         _video.clear ();
 148         _audio.clear ();
 149         _finished = false;
 150         _pending_seek_position = position;
 151         _pending_seek_accurate = accurate;
 152         _summon.notify_all ();
 153 }
 154
 155 void
 156 Butler::video (shared_ptr<PlayerVideo> video, DCPTime time)
 157 {
 158         {
 159                 boost::mutex::scoped_lock lm (_mutex);
 160                 if (_pending_seek_position) {
 161                         /* Don't store any video while a seek is pending */
 162                         return;
 163                 }
 164         }
 165
 166         _video.put (video, time);
 167 }
 168
 169 void
 170 Butler::audio (shared_ptr<AudioBuffers> audio, DCPTime time)
 171 {
 172         {
 173                 boost::mutex::scoped_lock lm (_mutex);
 174                 if (_pending_seek_position || _disable_audio) {
 175                         /* Don't store any audio while a seek is pending, or if audio is disabled */
 176                         return;
 177                 }
 178         }
 179
 180         _audio.put (audio, time);
 181 }
 182
 183 void
 184 Butler::player_changed ()
 185 {
 186         optional<DCPTime> t;
 187
 188         {
 189                 boost::mutex::scoped_lock lm (_mutex);
 190                 t = _video.earliest ();
 191         }
 192
 193         if (t) {
 194                 seek (*t, true);
 195         } else {
 196                 _video.clear ();
 197                 _audio.clear ();
 198         }
 199 }
 200
 201 void
 202 Butler::get_audio (float* out, Frame frames)
 203 {
 204         _audio.get (out, _audio_channels, frames);
 205         _summon.notify_all ();
 206 }
 207
 208 void
 209 Butler::disable_audio ()
 210 {
 211         boost::mutex::scoped_lock lm (_mutex);
 212         _disable_audio = true;
 213 }