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