src/wx/film_viewer.cc

   1 /*
   2     Copyright (C) 2012-2019 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 /** @file  src/film_viewer.cc
  22  *  @brief A wx widget to view a preview of a Film.
  23  */
  24
  25 #include "film_viewer.h"
  26 #include "playhead_to_timecode_dialog.h"
  27 #include "playhead_to_frame_dialog.h"
  28 #include "wx_util.h"
  29 #include "closed_captions_dialog.h"
  30 #include "lib/film.h"
  31 #include "lib/ratio.h"
  32 #include "lib/util.h"
  33 #include "lib/job_manager.h"
  34 #include "lib/image.h"
  35 #include "lib/exceptions.h"
  36 #include "lib/examine_content_job.h"
  37 #include "lib/filter.h"
  38 #include "lib/player.h"
  39 #include "lib/player_video.h"
  40 #include "lib/video_content.h"
  41 #include "lib/video_decoder.h"
  42 #include "lib/timer.h"
  43 #include "lib/butler.h"
  44 #include "lib/log.h"
  45 #include "lib/config.h"
  46 #include "lib/compose.hpp"
  47 #include "lib/dcpomatic_log.h"
  48 #include "lib/text_content.h"
  49 extern "C" {
  50 #include <libavutil/pixfmt.h>
  51 }
  52 #include <dcp/exceptions.h>
  53 #include <wx/tglbtn.h>
  54 #include <iostream>
  55 #include <iomanip>
  56
  57 using std::string;
  58 using std::pair;
  59 using std::min;
  60 using std::max;
  61 using std::cout;
  62 using std::list;
  63 using std::bad_alloc;
  64 using std::make_pair;
  65 using std::exception;
  66 using boost::shared_ptr;
  67 using boost::dynamic_pointer_cast;
  68 using boost::weak_ptr;
  69 using boost::optional;
  70 using dcp::Size;
  71
  72 static
  73 int
  74 rtaudio_callback (void* out, void *, unsigned int frames, double, RtAudioStreamStatus, void* data)
  75 {
  76         return reinterpret_cast<FilmViewer*>(data)->audio_callback (out, frames);
  77 }
  78
  79 FilmViewer::FilmViewer (wxWindow* p)
  80         : _panel (new wxPanel (p))
  81         , _coalesce_player_changes (false)
  82         , _audio (DCPOMATIC_RTAUDIO_API)
  83         , _audio_channels (0)
  84         , _audio_block_size (1024)
  85         , _playing (false)
  86         , _latency_history_count (0)
  87         , _dropped (0)
  88         , _closed_captions_dialog (new ClosedCaptionsDialog(p, this))
  89         , _outline_content (false)
  90         , _eyes (EYES_LEFT)
  91         , _pad_black (false)
  92 #ifdef DCPOMATIC_VARIANT_SWAROOP
  93         , _in_watermark (false)
  94         , _background_image (false)
  95 #endif
  96 {
  97 #ifndef __WXOSX__
  98         _panel->SetDoubleBuffered (true);
  99 #endif
 100
 101         _panel->SetBackgroundStyle (wxBG_STYLE_PAINT);
 102         _panel->SetBackgroundColour (*wxBLACK);
 103
 104         _panel->Bind (wxEVT_PAINT, boost::bind (&FilmViewer::paint_panel, this));
 105         _panel->Bind (wxEVT_SIZE,  boost::bind (&FilmViewer::panel_sized, this, _1));
 106         _timer.Bind  (wxEVT_TIMER, boost::bind (&FilmViewer::timer, this));
 107
 108         set_film (shared_ptr<Film> ());
 109
 110         _config_changed_connection = Config::instance()->Changed.connect (bind (&FilmViewer::config_changed, this, _1));
 111         config_changed (Config::SOUND_OUTPUT);
 112 }
 113
 114 FilmViewer::~FilmViewer ()
 115 {
 116         stop ();
 117 }
 118
 119 void
 120 FilmViewer::set_film (shared_ptr<Film> film)
 121 {
 122         if (_film == film) {
 123                 return;
 124         }
 125
 126         _film = film;
 127         _video_position = DCPTime ();
 128         _player_video.first.reset ();
 129         _player_video.second = DCPTime ();
 130
 131         _frame.reset ();
 132         _closed_captions_dialog->clear ();
 133
 134         if (!_film) {
 135                 _player.reset ();
 136                 recreate_butler ();
 137                 _frame.reset ();
 138                 refresh_panel ();
 139                 return;
 140         }
 141
 142         try {
 143                 _player.reset (new Player (_film, _film->playlist ()));
 144                 _player->set_fast ();
 145                 if (_dcp_decode_reduction) {
 146                         _player->set_dcp_decode_reduction (_dcp_decode_reduction);
 147                 }
 148         } catch (bad_alloc &) {
 149                 error_dialog (_panel, _("There is not enough free memory to do that."));
 150                 _film.reset ();
 151                 return;
 152         }
 153
 154         _player->set_always_burn_open_subtitles ();
 155         _player->set_play_referenced ();
 156
 157         _film->Change.connect (boost::bind (&FilmViewer::film_change, this, _1, _2));
 158         _film->ContentChange.connect (boost::bind(&FilmViewer::content_change, this, _1, _3));
 159         _player->Change.connect (boost::bind (&FilmViewer::player_change, this, _1, _2, _3));
 160
 161         /* Keep about 1 second's worth of history samples */
 162         _latency_history_count = _film->audio_frame_rate() / _audio_block_size;
 163
 164         _closed_captions_dialog->update_tracks (_film);
 165
 166         recreate_butler ();
 167
 168         calculate_sizes ();
 169         slow_refresh ();
 170 }
 171
 172 void
 173 FilmViewer::recreate_butler ()
 174 {
 175         bool const was_running = stop ();
 176         _butler.reset ();
 177
 178         if (!_film) {
 179                 return;
 180         }
 181
 182         AudioMapping map = AudioMapping (_film->audio_channels(), _audio_channels);
 183
 184         if (_audio_channels != 2 || _film->audio_channels() < 3) {
 185                 for (int i = 0; i < min (_film->audio_channels(), _audio_channels); ++i) {
 186                         map.set (i, i, 1);
 187                 }
 188         } else {
 189                 /* Special case: stereo output, at least 3 channel input.
 190                    Map so that Lt = L(-3dB) + Ls(-3dB) + C(-6dB) + Lfe(-10dB)
 191                                Rt = R(-3dB) + Rs(-3dB) + C(-6dB) + Lfe(-10dB)
 192                 */
 193                 if (_film->audio_channels() > 0) {
 194                         map.set (dcp::LEFT,   0, 1 / sqrt(2)); // L -> Lt
 195                 }
 196                 if (_film->audio_channels() > 1) {
 197                         map.set (dcp::RIGHT,  1, 1 / sqrt(2)); // R -> Rt
 198                 }
 199                 if (_film->audio_channels() > 2) {
 200                         map.set (dcp::CENTRE, 0, 1 / 2.0); // C -> Lt
 201                         map.set (dcp::CENTRE, 1, 1 / 2.0); // C -> Rt
 202                 }
 203                 if (_film->audio_channels() > 3) {
 204                         map.set (dcp::LFE,    0, 1 / sqrt(10)); // Lfe -> Lt
 205                         map.set (dcp::LFE,    1, 1 / sqrt(10)); // Lfe -> Rt
 206                 }
 207                 if (_film->audio_channels() > 4) {
 208                         map.set (dcp::LS,     0, 1 / sqrt(2)); // Ls -> Lt
 209                 }
 210                 if (_film->audio_channels() > 5) {
 211                         map.set (dcp::RS,     1, 1 / sqrt(2)); // Rs -> Rt
 212                 }
 213         }
 214
 215         _butler.reset (new Butler(_player, map, _audio_channels, bind(&PlayerVideo::force, _1, AV_PIX_FMT_RGB24), false, true));
 216         if (!Config::instance()->sound() && !_audio.isStreamOpen()) {
 217                 _butler->disable_audio ();
 218         }
 219
 220         _closed_captions_dialog->set_butler (_butler);
 221
 222         if (was_running) {
 223                 start ();
 224         }
 225 }
 226
 227 void
 228 FilmViewer::refresh_panel ()
 229 {
 230         _panel->Refresh ();
 231         _panel->Update ();
 232 }
 233
 234 void
 235 FilmViewer::get ()
 236 {
 237         DCPOMATIC_ASSERT (_butler);
 238
 239         do {
 240                 Butler::Error e;
 241                 _player_video = _butler->get_video (&e);
 242                 if (!_player_video.first && e == Butler::AGAIN) {
 243                         signal_manager->when_idle (boost::bind(&FilmViewer::get, this));
 244                         return;
 245                 }
 246         } while (
 247                 _player_video.first &&
 248                 _film->three_d() &&
 249                 _eyes != _player_video.first->eyes() &&
 250                 _player_video.first->eyes() != EYES_BOTH
 251                 );
 252
 253         try {
 254                 _butler->rethrow ();
 255         } catch (DecodeError& e) {
 256                 error_dialog (_panel, e.what());
 257         }
 258
 259         display_player_video ();
 260 }
 261
 262 void
 263 FilmViewer::display_player_video ()
 264 {
 265         if (!_player_video.first) {
 266                 _frame.reset ();
 267                 refresh_panel ();
 268                 return;
 269         }
 270
 271         if (_playing && (time() - _player_video.second) > one_video_frame()) {
 272                 /* Too late; just drop this frame before we try to get its image (which will be the time-consuming
 273                    part if this frame is J2K).
 274                 */
 275                 _video_position = _player_video.second;
 276                 ++_dropped;
 277                 return;
 278         }
 279
 280         /* In an ideal world, what we would do here is:
 281          *
 282          * 1. convert to XYZ exactly as we do in the DCP creation path.
 283          * 2. convert back to RGB for the preview display, compensating
 284          *    for the monitor etc. etc.
 285          *
 286          * but this is inefficient if the source is RGB.  Since we don't
 287          * (currently) care too much about the precise accuracy of the preview's
 288          * colour mapping (and we care more about its speed) we try to short-
 289          * circuit this "ideal" situation in some cases.
 290          *
 291          * The content's specified colour conversion indicates the colourspace
 292          * which the content is in (according to the user).
 293          *
 294          * PlayerVideo::image (bound to PlayerVideo::force) will take the source
 295          * image and convert it (from whatever the user has said it is) to RGB.
 296          */
 297
 298         _frame = _player_video.first->image (bind(&PlayerVideo::force, _1, AV_PIX_FMT_RGB24), false, true);
 299
 300         ImageChanged (_player_video.first);
 301
 302         _video_position = _player_video.second;
 303         _inter_position = _player_video.first->inter_position ();
 304         _inter_size = _player_video.first->inter_size ();
 305
 306         refresh_panel ();
 307
 308         _closed_captions_dialog->update (time());
 309 }
 310
 311 void
 312 FilmViewer::timer ()
 313 {
 314         if (!_film || !_playing) {
 315                 return;
 316         }
 317
 318         get ();
 319         PositionChanged ();
 320         DCPTime const next = _video_position + one_video_frame();
 321
 322         if (next >= _film->length()) {
 323                 stop ();
 324                 Finished ();
 325                 return;
 326         }
 327
 328         LOG_DEBUG_PLAYER("%1 -> %2; delay %3", next.seconds(), time().seconds(), max((next.seconds() - time().seconds()) * 1000, 1.0));
 329         _timer.Start (max ((next.seconds() - time().seconds()) * 1000, 1.0), wxTIMER_ONE_SHOT);
 330
 331         if (_butler) {
 332                 _butler->rethrow ();
 333         }
 334 }
 335
 336 bool
 337 #ifdef DCPOMATIC_VARIANT_SWAROOP
 338 FilmViewer::maybe_draw_background_image (wxPaintDC& dc)
 339 {
 340         optional<boost::filesystem::path> bg = Config::instance()->player_background_image();
 341         if (bg) {
 342                 wxImage image (std_to_wx(bg->string()));
 343                 wxBitmap bitmap (image);
 344                 dc.DrawBitmap (bitmap, max(0, (_panel_size.width - image.GetSize().GetWidth()) / 2), max(0, (_panel_size.height - image.GetSize().GetHeight()) / 2));
 345                 return true;
 346         }
 347
 348         return false;
 349 }
 350 #else
 351 FilmViewer::maybe_draw_background_image (wxPaintDC &)
 352 {
 353         return false;
 354 }
 355 #endif
 356
 357 void
 358 FilmViewer::paint_panel ()
 359 {
 360         wxPaintDC dc (_panel);
 361
 362 #ifdef DCPOMATIC_VARIANT_SWAROOP
 363         if (_background_image) {
 364                 dc.Clear ();
 365                 maybe_draw_background_image (dc);
 366                 return;
 367         }
 368 #endif
 369
 370         if (!_out_size.width || !_out_size.height || !_film || !_frame || _out_size != _frame->size()) {
 371                 dc.Clear ();
 372         } else {
 373
 374                 wxImage frame (_out_size.width, _out_size.height, _frame->data()[0], true);
 375                 wxBitmap frame_bitmap (frame);
 376                 dc.DrawBitmap (frame_bitmap, 0, max(0, (_panel_size.height - _out_size.height) / 2));
 377
 378 #ifdef DCPOMATIC_VARIANT_SWAROOP
 379                 DCPTime const period = DCPTime::from_seconds(Config::instance()->player_watermark_period() * 60);
 380                 int64_t n = _video_position.get() / period.get();
 381                 DCPTime from(n * period.get());
 382                 DCPTime to = from + DCPTime::from_seconds(Config::instance()->player_watermark_duration() / 1000.0);
 383                 if (from <= _video_position && _video_position <= to) {
 384                         if (!_in_watermark) {
 385                                 _in_watermark = true;
 386                                 _watermark_x = rand() % _panel_size.width;
 387                                 _watermark_y = rand() % _panel_size.height;
 388                         }
 389                         dc.SetTextForeground(*wxWHITE);
 390                         string wm = Config::instance()->player_watermark_theatre();
 391                         boost::posix_time::ptime t = boost::posix_time::second_clock::local_time();
 392                         wm += "\n" + boost::posix_time::to_iso_extended_string(t);
 393                         dc.DrawText(std_to_wx(wm), _watermark_x, _watermark_y);
 394                 } else {
 395                         _in_watermark = false;
 396                 }
 397 #endif
 398         }
 399
 400         if (_out_size.width < _panel_size.width) {
 401                 /* XXX: these colours are right for GNOME; may need adjusting for other OS */
 402                 wxPen   p (_pad_black ? wxColour(0, 0, 0) : wxColour(240, 240, 240));
 403                 wxBrush b (_pad_black ? wxColour(0, 0, 0) : wxColour(240, 240, 240));
 404                 dc.SetPen (p);
 405                 dc.SetBrush (b);
 406                 dc.DrawRectangle (_out_size.width, 0, _panel_size.width - _out_size.width, _panel_size.height);
 407         }
 408
 409         if (_out_size.height < _panel_size.height) {
 410                 wxPen   p (_pad_black ? wxColour(0, 0, 0) : wxColour(240, 240, 240));
 411                 wxBrush b (_pad_black ? wxColour(0, 0, 0) : wxColour(240, 240, 240));
 412                 dc.SetPen (p);
 413                 dc.SetBrush (b);
 414                 int const gap = (_panel_size.height - _out_size.height) / 2;
 415                 dc.DrawRectangle (0, 0, _panel_size.width, gap);
 416                 dc.DrawRectangle (0, gap + _out_size.height + 1, _panel_size.width, gap + 1);
 417         }
 418
 419         if (_outline_content) {
 420                 wxPen p (wxColour (255, 0, 0), 2);
 421                 dc.SetPen (p);
 422                 dc.SetBrush (*wxTRANSPARENT_BRUSH);
 423                 dc.DrawRectangle (_inter_position.x, _inter_position.y + (_panel_size.height - _out_size.height) / 2, _inter_size.width, _inter_size.height);
 424         }
 425 }
 426
 427 void
 428 FilmViewer::set_outline_content (bool o)
 429 {
 430         _outline_content = o;
 431         refresh_panel ();
 432 }
 433
 434 void
 435 FilmViewer::set_eyes (Eyes e)
 436 {
 437         _eyes = e;
 438         slow_refresh ();
 439 }
 440
 441 void
 442 FilmViewer::panel_sized (wxSizeEvent& ev)
 443 {
 444         _panel_size.width = ev.GetSize().GetWidth();
 445         _panel_size.height = ev.GetSize().GetHeight();
 446
 447         calculate_sizes ();
 448         if (!quick_refresh()) {
 449                 slow_refresh ();
 450         }
 451         PositionChanged ();
 452 }
 453
 454 void
 455 FilmViewer::calculate_sizes ()
 456 {
 457         if (!_film || !_player) {
 458                 return;
 459         }
 460
 461         Ratio const * container = _film->container ();
 462
 463         float const panel_ratio = _panel_size.ratio ();
 464         float const film_ratio = container ? container->ratio () : 1.78;
 465
 466         if (panel_ratio < film_ratio) {
 467                 /* panel is less widscreen than the film; clamp width */
 468                 _out_size.width = _panel_size.width;
 469                 _out_size.height = lrintf (_out_size.width / film_ratio);
 470         } else {
 471                 /* panel is more widescreen than the film; clamp height */
 472                 _out_size.height = _panel_size.height;
 473                 _out_size.width = lrintf (_out_size.height * film_ratio);
 474         }
 475
 476         /* Catch silly values */
 477         _out_size.width = max (64, _out_size.width);
 478         _out_size.height = max (64, _out_size.height);
 479
 480         _player->set_video_container_size (_out_size);
 481 }
 482
 483 void
 484 FilmViewer::start ()
 485 {
 486         if (!_film) {
 487                 return;
 488         }
 489
 490         optional<bool> v = PlaybackPermitted ();
 491         if (v && !*v) {
 492                 /* Computer says no */
 493                 return;
 494         }
 495
 496         if (_audio.isStreamOpen()) {
 497                 _audio.setStreamTime (_video_position.seconds());
 498                 _audio.startStream ();
 499         }
 500
 501         _playing = true;
 502         _dropped = 0;
 503         timer ();
 504         Started (position());
 505 }
 506
 507 bool
 508 FilmViewer::stop ()
 509 {
 510         if (_audio.isStreamRunning()) {
 511                 /* stop stream and discard any remaining queued samples */
 512                 _audio.abortStream ();
 513         }
 514
 515         if (!_playing) {
 516                 return false;
 517         }
 518
 519         _playing = false;
 520         Stopped (position());
 521         return true;
 522 }
 523
 524 void
 525 FilmViewer::player_change (ChangeType type, int property, bool frequent)
 526 {
 527         if (type != CHANGE_TYPE_DONE || frequent) {
 528                 return;
 529         }
 530
 531         if (_coalesce_player_changes) {
 532                 _pending_player_changes.push_back (property);
 533                 return;
 534         }
 535
 536         calculate_sizes ();
 537         bool refreshed = false;
 538         if (
 539                 property == VideoContentProperty::CROP ||
 540                 property == VideoContentProperty::SCALE ||
 541                 property == VideoContentProperty::FADE_IN ||
 542                 property == VideoContentProperty::FADE_OUT ||
 543                 property == VideoContentProperty::COLOUR_CONVERSION ||
 544                 property == PlayerProperty::VIDEO_CONTAINER_SIZE ||
 545                 property == PlayerProperty::FILM_CONTAINER
 546                 ) {
 547                 refreshed = quick_refresh ();
 548         }
 549
 550         if (!refreshed) {
 551                 slow_refresh ();
 552         }
 553         PositionChanged ();
 554 }
 555
 556 void
 557 FilmViewer::film_change (ChangeType type, Film::Property p)
 558 {
 559         if (type == CHANGE_TYPE_DONE && p == Film::AUDIO_CHANNELS) {
 560                 recreate_butler ();
 561         } else if (p == Film::CONTENT) {
 562                 _closed_captions_dialog->update_tracks (_film);
 563         }
 564 }
 565
 566 /** Re-get the current frame slowly by seeking */
 567 void
 568 FilmViewer::slow_refresh ()
 569 {
 570         seek (_video_position, true);
 571 }
 572
 573 /** Try to re-get the current frame quickly by resetting the metadata
 574  *  in the PlayerVideo that we used last time.
 575  *  @return true if this was possible, false if not.
 576  */
 577 bool
 578 FilmViewer::quick_refresh ()
 579 {
 580         if (!_player_video.first) {
 581                 return false;
 582         }
 583
 584         if (!_player_video.first->reset_metadata (_film, _player->video_container_size(), _film->frame_size())) {
 585                 return false;
 586         }
 587
 588         display_player_video ();
 589         return true;
 590 }
 591
 592 void
 593 FilmViewer::seek (shared_ptr<Content> content, ContentTime t, bool accurate)
 594 {
 595         optional<DCPTime> dt = _player->content_time_to_dcp (content, t);
 596         if (dt) {
 597                 seek (*dt, accurate);
 598         }
 599 }
 600
 601 void
 602 FilmViewer::set_coalesce_player_changes (bool c)
 603 {
 604         _coalesce_player_changes = c;
 605
 606         if (!c) {
 607                 BOOST_FOREACH (int i, _pending_player_changes) {
 608                         player_change (CHANGE_TYPE_DONE, i, false);
 609                 }
 610                 _pending_player_changes.clear ();
 611         }
 612 }
 613
 614 void
 615 FilmViewer::seek (DCPTime t, bool accurate)
 616 {
 617         if (!_butler) {
 618                 return;
 619         }
 620
 621         if (t < DCPTime ()) {
 622                 t = DCPTime ();
 623         }
 624
 625         if (t >= _film->length ()) {
 626                 t = _film->length ();
 627         }
 628
 629         bool const was_running = stop ();
 630
 631         _closed_captions_dialog->clear ();
 632         _butler->seek (t, accurate);
 633         get ();
 634
 635         if (was_running) {
 636                 start ();
 637         }
 638
 639         PositionChanged ();
 640 }
 641
 642 void
 643 FilmViewer::config_changed (Config::Property p)
 644 {
 645 #ifdef DCPOMATIC_VARIANT_SWAROOP
 646         if (p == Config::PLAYER_BACKGROUND_IMAGE) {
 647                 refresh_panel ();
 648                 return;
 649         }
 650 #endif
 651
 652         if (p != Config::SOUND && p != Config::SOUND_OUTPUT) {
 653                 return;
 654         }
 655
 656         if (_audio.isStreamOpen ()) {
 657                 _audio.closeStream ();
 658         }
 659
 660         if (Config::instance()->sound() && _audio.getDeviceCount() > 0) {
 661                 unsigned int st = 0;
 662                 if (Config::instance()->sound_output()) {
 663                         while (st < _audio.getDeviceCount()) {
 664                                 if (_audio.getDeviceInfo(st).name == Config::instance()->sound_output().get()) {
 665                                         break;
 666                                 }
 667                                 ++st;
 668                         }
 669                         if (st == _audio.getDeviceCount()) {
 670                                 st = _audio.getDefaultOutputDevice();
 671                         }
 672                 } else {
 673                         st = _audio.getDefaultOutputDevice();
 674                 }
 675
 676                 _audio_channels = _audio.getDeviceInfo(st).outputChannels;
 677
 678                 RtAudio::StreamParameters sp;
 679                 sp.deviceId = st;
 680                 sp.nChannels = _audio_channels;
 681                 sp.firstChannel = 0;
 682                 try {
 683                         _audio.openStream (&sp, 0, RTAUDIO_FLOAT32, 48000, &_audio_block_size, &rtaudio_callback, this);
 684 #ifdef DCPOMATIC_USE_RTERROR
 685                 } catch (RtError& e) {
 686 #else
 687                 } catch (RtAudioError& e) {
 688 #endif
 689                         error_dialog (
 690                                 _panel,
 691                                 _("Could not set up audio output.  There will be no audio during the preview."), std_to_wx(e.what())
 692                                 );
 693                 }
 694                 recreate_butler ();
 695
 696         } else {
 697                 _audio_channels = 0;
 698                 recreate_butler ();
 699         }
 700 }
 701
 702 DCPTime
 703 FilmViewer::uncorrected_time () const
 704 {
 705         if (_audio.isStreamRunning ()) {
 706                 return DCPTime::from_seconds (const_cast<RtAudio*>(&_audio)->getStreamTime());
 707         }
 708
 709         return _video_position;
 710 }
 711
 712 DCPTime
 713 FilmViewer::time () const
 714 {
 715         if (_audio.isStreamRunning ()) {
 716                 return DCPTime::from_seconds (const_cast<RtAudio*>(&_audio)->getStreamTime ()) -
 717                         DCPTime::from_frames (average_latency(), _film->audio_frame_rate());
 718         }
 719
 720         return _video_position;
 721 }
 722
 723 int
 724 FilmViewer::audio_callback (void* out_p, unsigned int frames)
 725 {
 726         while (true) {
 727                 optional<DCPTime> t = _butler->get_audio (reinterpret_cast<float*> (out_p), frames);
 728                 if (!t || DCPTime(uncorrected_time() - *t) < one_video_frame()) {
 729                         /* There was an underrun or this audio is on time; carry on */
 730                         break;
 731                 }
 732                 /* The audio we just got was (very) late; drop it and get some more. */
 733         }
 734
 735         boost::mutex::scoped_lock lm (_latency_history_mutex, boost::try_to_lock);
 736         if (lm) {
 737                 _latency_history.push_back (_audio.getStreamLatency ());
 738                 if (_latency_history.size() > static_cast<size_t> (_latency_history_count)) {
 739                         _latency_history.pop_front ();
 740                 }
 741         }
 742
 743         return 0;
 744 }
 745
 746 Frame
 747 FilmViewer::average_latency () const
 748 {
 749         boost::mutex::scoped_lock lm (_latency_history_mutex);
 750         if (_latency_history.empty()) {
 751                 return 0;
 752         }
 753
 754         Frame total = 0;
 755         BOOST_FOREACH (Frame i, _latency_history) {
 756                 total += i;
 757         }
 758
 759         return total / _latency_history.size();
 760 }
 761
 762 void
 763 FilmViewer::set_dcp_decode_reduction (optional<int> reduction)
 764 {
 765         _dcp_decode_reduction = reduction;
 766         if (_player) {
 767                 _player->set_dcp_decode_reduction (reduction);
 768         }
 769 }
 770
 771 optional<int>
 772 FilmViewer::dcp_decode_reduction () const
 773 {
 774         return _dcp_decode_reduction;
 775 }
 776
 777 DCPTime
 778 FilmViewer::one_video_frame () const
 779 {
 780         return DCPTime::from_frames (1, _film->video_frame_rate());
 781 }
 782
 783 /** Open a dialog box showing our film's closed captions */
 784 void
 785 FilmViewer::show_closed_captions ()
 786 {
 787         _closed_captions_dialog->Show();
 788 }
 789
 790 void
 791 FilmViewer::seek_by (DCPTime by, bool accurate)
 792 {
 793         seek (_video_position + by, accurate);
 794 }
 795
 796 void
 797 FilmViewer::set_pad_black (bool p)
 798 {
 799         _pad_black = p;
 800 }
 801
 802 void
 803 FilmViewer::content_change (ChangeType type, int property)
 804 {
 805         if (type != CHANGE_TYPE_DONE) {
 806                 return;
 807         }
 808
 809         if (property == TextContentProperty::USE || property == TextContentProperty::TYPE || property == TextContentProperty::DCP_TRACK) {
 810                 _closed_captions_dialog->update_tracks (_film);
 811         }
 812 }