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
  37 Butler::Butler (weak_ptr<const Film> film, shared_ptr<Player> player, AudioMapping audio_mapping, int audio_channels)
  38         : _film (film)
  39         , _player (player)
  40         , _pending_seek_accurate (false)
  41         , _finished (false)
  42         , _audio_mapping (audio_mapping)
  43         , _audio_channels (audio_channels)
  44         , _stop_thread (false)
  45 {
  46         _player_video_connection = _player->Video.connect (bind (&Butler::video, this, _1, _2));
  47         _player_audio_connection = _player->Audio.connect (bind (&Butler::audio, this, _1, _2));
  48         _player_changed_connection = _player->Changed.connect (bind (&Butler::player_changed, this));
  49         _thread = new boost::thread (bind (&Butler::thread, this));
  50 }
  51
  52 Butler::~Butler ()
  53 {
  54         _stop_thread = true;
  55         _thread->interrupt ();
  56         try {
  57                 _thread->join ();
  58         } catch (boost::thread_interrupted& e) {
  59                 /* No problem */
  60         }
  61         delete _thread;
  62 }
  63
  64 void
  65 Butler::thread ()
  66 try
  67 {
  68         while (true) {
  69                 boost::mutex::scoped_lock lm (_mutex);
  70
  71                 /* Wait until we have something to do */
  72                 while ((_video.size() >= VIDEO_READAHEAD && !_pending_seek_position) || _stop_thread) {
  73                         _summon.wait (lm);
  74                 }
  75
  76                 /* Do any seek that has been requested */
  77                 if (_pending_seek_position) {
  78                         _player->seek (*_pending_seek_position, _pending_seek_accurate);
  79                         _pending_seek_position = optional<DCPTime> ();
  80                 }
  81
  82                 /* Fill _video.  Don't try to carry on if a pending seek appears
  83                    while lm is unlocked, as in that state nothing will be added to
  84                    _video.
  85                 */
  86                 while (_video.size() < VIDEO_READAHEAD && !_pending_seek_position && !_stop_thread) {
  87                         lm.unlock ();
  88                         if (_player->pass ()) {
  89                                 _finished = true;
  90                                 _arrived.notify_all ();
  91                                 break;
  92                         }
  93                         lm.lock ();
  94                         _arrived.notify_all ();
  95                 }
  96         }
  97 } catch (boost::thread_interrupted) {
  98         /* The butler thread is being terminated */
  99 }
 100
 101 pair<shared_ptr<PlayerVideo>, DCPTime>
 102 Butler::get_video ()
 103 {
 104         boost::mutex::scoped_lock lm (_mutex);
 105
 106         /* Wait for data if we have none */
 107         while (_video.empty() && !_finished) {
 108                 _arrived.wait (lm);
 109         }
 110
 111         if (_finished) {
 112                 return make_pair (shared_ptr<PlayerVideo>(), DCPTime());
 113         }
 114
 115         pair<shared_ptr<PlayerVideo>, DCPTime> const r = _video.get ();
 116         _summon.notify_all ();
 117         return r;
 118 }
 119
 120 void
 121 Butler::seek (DCPTime position, bool accurate)
 122 {
 123         boost::mutex::scoped_lock lm (_mutex);
 124         _video.clear ();
 125         _finished = false;
 126         _pending_seek_position = position;
 127         _pending_seek_accurate = accurate;
 128         _summon.notify_all ();
 129 }
 130
 131 void
 132 Butler::video (shared_ptr<PlayerVideo> video, DCPTime time)
 133 {
 134         {
 135                 boost::mutex::scoped_lock lm (_mutex);
 136                 if (_pending_seek_position) {
 137                         /* Don't store any video while a seek is pending */
 138                         return;
 139                 }
 140         }
 141
 142         _video.put (video, time);
 143 }
 144
 145 void
 146 Butler::audio (shared_ptr<AudioBuffers> audio, DCPTime time)
 147 {
 148
 149 }
 150
 151 void
 152 Butler::player_changed ()
 153 {
 154         optional<DCPTime> t;
 155
 156         {
 157                 boost::mutex::scoped_lock lm (_mutex);
 158                 t = _video.earliest ();
 159         }
 160
 161         if (t) {
 162                 seek (*t, true);
 163         }
 164 }
 165
 166 void
 167 Butler::get_audio (float* out, Frame frames)
 168 {
 169         _audio.get (reinterpret_cast<float*> (out), _audio_channels, frames);
 170         _summon.notify_all ();
 171 }