src/wx/film_viewer.cc

   1 /*
   2     Copyright (C) 2012-2018 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 extern "C" {
  48 #include <libavutil/pixfmt.h>
  49 }
  50 #include <dcp/exceptions.h>
  51 #include <wx/tglbtn.h>
  52 #include <iostream>
  53 #include <iomanip>
  54
  55 using std::string;
  56 using std::pair;
  57 using std::min;
  58 using std::max;
  59 using std::cout;
  60 using std::list;
  61 using std::bad_alloc;
  62 using std::make_pair;
  63 using std::exception;
  64 using boost::shared_ptr;
  65 using boost::dynamic_pointer_cast;
  66 using boost::weak_ptr;
  67 using boost::optional;
  68 using dcp::Size;
  69
  70 static
  71 int
  72 rtaudio_callback (void* out, void *, unsigned int frames, double, RtAudioStreamStatus, void* data)
  73 {
  74         return reinterpret_cast<FilmViewer*>(data)->audio_callback (out, frames);
  75 }
  76
  77 FilmViewer::FilmViewer (wxWindow* p)
  78         : _panel (new wxPanel (p))
  79         , _coalesce_player_changes (false)
  80         , _audio (DCPOMATIC_RTAUDIO_API)
  81         , _audio_channels (0)
  82         , _audio_block_size (1024)
  83         , _playing (false)
  84         , _latency_history_count (0)
  85         , _dropped (0)
  86         , _closed_captions_dialog (new ClosedCaptionsDialog(p))
  87         , _outline_content (false)
  88         , _eyes (EYES_LEFT)
  89         , _pad_black (false)
  90 #ifdef DCPOMATIC_VARIANT_SWAROOP
  91         , _in_watermark (false)
  92         , _background_image (false)
  93 #endif
  94 {
  95 #ifndef __WXOSX__
  96         _panel->SetDoubleBuffered (true);
  97 #endif
  98
  99         _panel->SetBackgroundStyle (wxBG_STYLE_PAINT);
 100         _panel->SetBackgroundColour (*wxBLACK);
 101
 102         _panel->Bind (wxEVT_PAINT, boost::bind (&FilmViewer::paint_panel, this));
 103         _panel->Bind (wxEVT_SIZE,  boost::bind (&FilmViewer::panel_sized, this, _1));
 104         _timer.Bind  (wxEVT_TIMER, boost::bind (&FilmViewer::timer, this));
 105
 106         set_film (shared_ptr<Film> ());
 107
 108         _config_changed_connection = Config::instance()->Changed.connect (bind (&FilmViewer::config_changed, this, _1));
 109         config_changed (Config::SOUND_OUTPUT);
 110 }
 111
 112 FilmViewer::~FilmViewer ()
 113 {
 114         stop ();
 115 }
 116
 117 void
 118 FilmViewer::set_film (shared_ptr<Film> film)
 119 {
 120         if (_film == film) {
 121                 return;
 122         }
 123
 124         _film = film;
 125         _video_position = DCPTime ();
 126         _player_video.first.reset ();
 127         _player_video.second = DCPTime ();
 128
 129         _frame.reset ();
 130         _closed_captions_dialog->clear ();
 131
 132         if (!_film) {
 133                 _player.reset ();
 134                 recreate_butler ();
 135                 _frame.reset ();
 136                 refresh_panel ();
 137                 return;
 138         }
 139
 140         try {
 141                 _player.reset (new Player (_film, _film->playlist ()));
 142                 _player->set_fast ();
 143                 if (_dcp_decode_reduction) {
 144                         _player->set_dcp_decode_reduction (_dcp_decode_reduction);
 145                 }
 146         } catch (bad_alloc &) {
 147                 error_dialog (_panel, _("There is not enough free memory to do that."));
 148                 _film.reset ();
 149                 return;
 150         }
 151
 152         _player->set_always_burn_open_subtitles ();
 153         _player->set_play_referenced ();
 154
 155         _film->Change.connect (boost::bind (&FilmViewer::film_change, this, _1, _2));
 156         _player->Change.connect (boost::bind (&FilmViewer::player_change, this, _1, _2, _3));
 157
 158         /* Keep about 1 second's worth of history samples */
 159         _latency_history_count = _film->audio_frame_rate() / _audio_block_size;
 160
 161         recreate_butler ();
 162
 163         calculate_sizes ();
 164         slow_refresh ();
 165 }
 166
 167 void
 168 FilmViewer::recreate_butler ()
 169 {
 170         bool const was_running = stop ();
 171         _butler.reset ();
 172
 173         if (!_film) {
 174                 return;
 175         }
 176
 177         AudioMapping map = AudioMapping (_film->audio_channels(), _audio_channels);
 178
 179         if (_audio_channels != 2 || _film->audio_channels() < 3) {
 180                 for (int i = 0; i < min (_film->audio_channels(), _audio_channels); ++i) {
 181                         map.set (i, i, 1);
 182                 }
 183         } else {
 184                 /* Special case: stereo output, at least 3 channel input.
 185                    Map so that Lt = L(-3dB) + Ls(-3dB) + C(-6dB) + Lfe(-10dB)
 186                                Rt = R(-3dB) + Rs(-3dB) + C(-6dB) + Lfe(-10dB)
 187                 */
 188                 map.set (dcp::LEFT,   0, 1 / sqrt(2)); // L -> Lt
 189                 map.set (dcp::RIGHT,  1, 1 / sqrt(2)); // R -> Rt
 190                 map.set (dcp::CENTRE, 0, 1 / 2.0); // C -> Lt
 191                 map.set (dcp::CENTRE, 1, 1 / 2.0); // C -> Rt
 192                 map.set (dcp::LFE,    0, 1 / sqrt(10)); // Lfe -> Lt
 193                 map.set (dcp::LFE,    1, 1 / sqrt(10)); // Lfe -> Rt
 194                 map.set (dcp::LS,     0, 1 / sqrt(2)); // Ls -> Lt
 195                 map.set (dcp::RS,     1, 1 / sqrt(2)); // Rs -> Rt
 196         }
 197
 198         _butler.reset (new Butler(_player, map, _audio_channels, bind(&PlayerVideo::force, _1, AV_PIX_FMT_RGB24), false, true));
 199         if (!Config::instance()->sound() && !_audio.isStreamOpen()) {
 200                 _butler->disable_audio ();
 201         }
 202
 203         _closed_captions_dialog->set_butler (_butler);
 204
 205         if (was_running) {
 206                 start ();
 207         }
 208 }
 209
 210 void
 211 FilmViewer::refresh_panel ()
 212 {
 213         _panel->Refresh ();
 214         _panel->Update ();
 215 }
 216
 217 void
 218 FilmViewer::get ()
 219 {
 220         DCPOMATIC_ASSERT (_butler);
 221
 222         do {
 223                 Butler::Error e;
 224                 _player_video = _butler->get_video (&e);
 225                 if (!_player_video.first && e == Butler::AGAIN) {
 226                         signal_manager->when_idle (boost::bind(&FilmViewer::get, this));
 227                         return;
 228                 }
 229         } while (
 230                 _player_video.first &&
 231                 _film->three_d() &&
 232                 _eyes != _player_video.first->eyes() &&
 233                 _player_video.first->eyes() != EYES_BOTH
 234                 );
 235
 236         _butler->rethrow ();
 237
 238         display_player_video ();
 239 }
 240
 241 void
 242 FilmViewer::display_player_video ()
 243 {
 244         if (!_player_video.first) {
 245                 _frame.reset ();
 246                 refresh_panel ();
 247                 return;
 248         }
 249
 250         if (_playing && (time() - _player_video.second) > one_video_frame()) {
 251                 /* Too late; just drop this frame before we try to get its image (which will be the time-consuming
 252                    part if this frame is J2K).
 253                 */
 254                 _video_position = _player_video.second;
 255                 ++_dropped;
 256                 return;
 257         }
 258
 259         /* In an ideal world, what we would do here is:
 260          *
 261          * 1. convert to XYZ exactly as we do in the DCP creation path.
 262          * 2. convert back to RGB for the preview display, compensating
 263          *    for the monitor etc. etc.
 264          *
 265          * but this is inefficient if the source is RGB.  Since we don't
 266          * (currently) care too much about the precise accuracy of the preview's
 267          * colour mapping (and we care more about its speed) we try to short-
 268          * circuit this "ideal" situation in some cases.
 269          *
 270          * The content's specified colour conversion indicates the colourspace
 271          * which the content is in (according to the user).
 272          *
 273          * PlayerVideo::image (bound to PlayerVideo::force) will take the source
 274          * image and convert it (from whatever the user has said it is) to RGB.
 275          */
 276
 277         _frame = _player_video.first->image (bind(&PlayerVideo::force, _1, AV_PIX_FMT_RGB24), false, true);
 278
 279         ImageChanged (_player_video.first);
 280
 281         _video_position = _player_video.second;
 282         _inter_position = _player_video.first->inter_position ();
 283         _inter_size = _player_video.first->inter_size ();
 284
 285         refresh_panel ();
 286
 287         _closed_captions_dialog->update (time());
 288 }
 289
 290 void
 291 FilmViewer::timer ()
 292 {
 293         if (!_film || !_playing) {
 294                 return;
 295         }
 296
 297         get ();
 298         PositionChanged ();
 299         DCPTime const next = _video_position + one_video_frame();
 300
 301         if (next >= _film->length()) {
 302                 stop ();
 303                 Finished ();
 304                 return;
 305         }
 306
 307         _timer.Start (max ((next.seconds() - time().seconds()) * 1000, 1.0), wxTIMER_ONE_SHOT);
 308
 309         if (_butler) {
 310                 _butler->rethrow ();
 311         }
 312 }
 313
 314 bool
 315 #ifdef DCPOMATIC_VARIANT_SWAROOP
 316 FilmViewer::maybe_draw_background_image (wxPaintDC& dc)
 317 {
 318         optional<boost::filesystem::path> bg = Config::instance()->player_background_image();
 319         if (bg) {
 320                 wxImage image (std_to_wx(bg->string()));
 321                 wxBitmap bitmap (image);
 322                 dc.DrawBitmap (bitmap, max(0, (_panel_size.width - image.GetSize().GetWidth()) / 2), max(0, (_panel_size.height - image.GetSize().GetHeight()) / 2));
 323                 return true;
 324         }
 325
 326         return false;
 327 }
 328 #else
 329 FilmViewer::maybe_draw_background_image (wxPaintDC &)
 330 {
 331         return false;
 332 }
 333 #endif
 334
 335 void
 336 FilmViewer::paint_panel ()
 337 {
 338         wxPaintDC dc (_panel);
 339
 340 #ifdef DCPOMATIC_VARIANT_SWAROOP
 341         if (_background_image) {
 342                 dc.Clear ();
 343                 maybe_draw_background_image (dc);
 344                 return;
 345         }
 346 #endif
 347
 348         if (!_out_size.width || !_out_size.height || !_film || !_frame || _out_size != _frame->size()) {
 349                 dc.Clear ();
 350                 return;
 351         }
 352
 353         wxImage frame (_out_size.width, _out_size.height, _frame->data()[0], true);
 354         wxBitmap frame_bitmap (frame);
 355         dc.DrawBitmap (frame_bitmap, 0, max(0, (_panel_size.height - _out_size.height) / 2));
 356
 357 #ifdef DCPOMATIC_VARIANT_SWAROOP
 358         DCPTime const period = DCPTime::from_seconds(Config::instance()->player_watermark_period() * 60);
 359         int64_t n = _video_position.get() / period.get();
 360         DCPTime from(n * period.get());
 361         DCPTime to = from + DCPTime::from_seconds(Config::instance()->player_watermark_duration() / 1000.0);
 362         if (from <= _video_position && _video_position <= to) {
 363                 if (!_in_watermark) {
 364                         _in_watermark = true;
 365                         _watermark_x = rand() % _panel_size.width;
 366                         _watermark_y = rand() % _panel_size.height;
 367                 }
 368                 dc.SetTextForeground(*wxWHITE);
 369                 string wm = Config::instance()->player_watermark_theatre();
 370                 boost::posix_time::ptime t = boost::posix_time::second_clock::local_time();
 371                 wm += "\n" + boost::posix_time::to_iso_extended_string(t);
 372                 dc.DrawText(std_to_wx(wm), _watermark_x, _watermark_y);
 373         } else {
 374                 _in_watermark = false;
 375         }
 376 #endif
 377
 378         if (_out_size.width < _panel_size.width) {
 379                 /* XXX: these colours are right for GNOME; may need adjusting for other OS */
 380                 wxPen   p (_pad_black ? wxColour(0, 0, 0) : wxColour(240, 240, 240));
 381                 wxBrush b (_pad_black ? wxColour(0, 0, 0) : wxColour(240, 240, 240));
 382                 dc.SetPen (p);
 383                 dc.SetBrush (b);
 384                 dc.DrawRectangle (_out_size.width, 0, _panel_size.width - _out_size.width, _panel_size.height);
 385         }
 386
 387         if (_out_size.height < _panel_size.height) {
 388                 wxPen   p (_pad_black ? wxColour(0, 0, 0) : wxColour(240, 240, 240));
 389                 wxBrush b (_pad_black ? wxColour(0, 0, 0) : wxColour(240, 240, 240));
 390                 dc.SetPen (p);
 391                 dc.SetBrush (b);
 392                 int const gap = (_panel_size.height - _out_size.height) / 2;
 393                 dc.DrawRectangle (0, 0, _panel_size.width, gap);
 394                 dc.DrawRectangle (0, gap + _out_size.height + 1, _panel_size.width, gap);
 395         }
 396
 397         if (_outline_content) {
 398                 wxPen p (wxColour (255, 0, 0), 2);
 399                 dc.SetPen (p);
 400                 dc.SetBrush (*wxTRANSPARENT_BRUSH);
 401                 dc.DrawRectangle (_inter_position.x, _inter_position.y + (_panel_size.height - _out_size.height) / 2, _inter_size.width, _inter_size.height);
 402         }
 403 }
 404
 405 void
 406 FilmViewer::set_outline_content (bool o)
 407 {
 408         _outline_content = o;
 409         refresh_panel ();
 410 }
 411
 412 void
 413 FilmViewer::set_eyes (Eyes e)
 414 {
 415         _eyes = e;
 416         slow_refresh ();
 417 }
 418
 419 void
 420 FilmViewer::panel_sized (wxSizeEvent& ev)
 421 {
 422         _panel_size.width = ev.GetSize().GetWidth();
 423         _panel_size.height = ev.GetSize().GetHeight();
 424
 425         calculate_sizes ();
 426         if (!quick_refresh()) {
 427                 slow_refresh ();
 428         }
 429         PositionChanged ();
 430 }
 431
 432 void
 433 FilmViewer::calculate_sizes ()
 434 {
 435         if (!_film || !_player) {
 436                 return;
 437         }
 438
 439         Ratio const * container = _film->container ();
 440
 441         float const panel_ratio = _panel_size.ratio ();
 442         float const film_ratio = container ? container->ratio () : 1.78;
 443
 444         if (panel_ratio < film_ratio) {
 445                 /* panel is less widscreen than the film; clamp width */
 446                 _out_size.width = _panel_size.width;
 447                 _out_size.height = lrintf (_out_size.width / film_ratio);
 448         } else {
 449                 /* panel is more widescreen than the film; clamp height */
 450                 _out_size.height = _panel_size.height;
 451                 _out_size.width = lrintf (_out_size.height * film_ratio);
 452         }
 453
 454         /* Catch silly values */
 455         _out_size.width = max (64, _out_size.width);
 456         _out_size.height = max (64, _out_size.height);
 457
 458         _player->set_video_container_size (_out_size);
 459 }
 460
 461 void
 462 FilmViewer::start ()
 463 {
 464         if (!_film) {
 465                 return;
 466         }
 467
 468         optional<bool> v = PlaybackPermitted ();
 469         if (v && !*v) {
 470                 /* Computer says no */
 471                 return;
 472         }
 473
 474         if (_audio.isStreamOpen()) {
 475                 _audio.setStreamTime (_video_position.seconds());
 476                 _audio.startStream ();
 477         }
 478
 479         _playing = true;
 480         _dropped = 0;
 481         timer ();
 482         Started (position());
 483 }
 484
 485 bool
 486 FilmViewer::stop ()
 487 {
 488         if (_audio.isStreamRunning()) {
 489                 /* stop stream and discard any remaining queued samples */
 490                 _audio.abortStream ();
 491         }
 492
 493         if (!_playing) {
 494                 return false;
 495         }
 496
 497         _playing = false;
 498         Stopped (position());
 499         return true;
 500 }
 501
 502 void
 503 FilmViewer::player_change (ChangeType type, int property, bool frequent)
 504 {
 505         if (type != CHANGE_TYPE_DONE || frequent) {
 506                 return;
 507         }
 508
 509         if (_coalesce_player_changes) {
 510                 _pending_player_changes.push_back (property);
 511                 return;
 512         }
 513
 514         calculate_sizes ();
 515         bool refreshed = false;
 516         if (
 517                 property == VideoContentProperty::CROP ||
 518                 property == VideoContentProperty::SCALE ||
 519                 property == VideoContentProperty::FADE_IN ||
 520                 property == VideoContentProperty::FADE_OUT ||
 521                 property == VideoContentProperty::COLOUR_CONVERSION ||
 522                 property == PlayerProperty::VIDEO_CONTAINER_SIZE ||
 523                 property == PlayerProperty::FILM_CONTAINER
 524                 ) {
 525                 refreshed = quick_refresh ();
 526         }
 527
 528         if (!refreshed) {
 529                 slow_refresh ();
 530         }
 531         PositionChanged ();
 532 }
 533
 534 void
 535 FilmViewer::film_change (ChangeType type, Film::Property p)
 536 {
 537         if (type == CHANGE_TYPE_DONE && p == Film::AUDIO_CHANNELS) {
 538                 recreate_butler ();
 539         }
 540 }
 541
 542 /** Re-get the current frame slowly by seeking */
 543 void
 544 FilmViewer::slow_refresh ()
 545 {
 546         seek (_video_position, true);
 547 }
 548
 549 /** Try to re-get the current frame quickly by resetting the metadata
 550  *  in the PlayerVideo that we used last time.
 551  *  @return true if this was possible, false if not.
 552  */
 553 bool
 554 FilmViewer::quick_refresh ()
 555 {
 556         if (!_player_video.first) {
 557                 return false;
 558         }
 559
 560         if (!_player_video.first->reset_metadata (_film, _player->video_container_size(), _film->frame_size())) {
 561                 return false;
 562         }
 563
 564         display_player_video ();
 565         return true;
 566 }
 567
 568 void
 569 FilmViewer::seek (shared_ptr<Content> content, ContentTime t, bool accurate)
 570 {
 571         optional<DCPTime> dt = _player->content_time_to_dcp (content, t);
 572         if (dt) {
 573                 seek (*dt, accurate);
 574         }
 575 }
 576
 577 void
 578 FilmViewer::set_coalesce_player_changes (bool c)
 579 {
 580         _coalesce_player_changes = c;
 581
 582         if (!c) {
 583                 BOOST_FOREACH (int i, _pending_player_changes) {
 584                         player_change (CHANGE_TYPE_DONE, i, false);
 585                 }
 586                 _pending_player_changes.clear ();
 587         }
 588 }
 589
 590 void
 591 FilmViewer::seek (DCPTime t, bool accurate)
 592 {
 593         if (!_butler) {
 594                 return;
 595         }
 596
 597         if (t < DCPTime ()) {
 598                 t = DCPTime ();
 599         }
 600
 601         if (t >= _film->length ()) {
 602                 t = _film->length ();
 603         }
 604
 605         bool const was_running = stop ();
 606
 607         _closed_captions_dialog->clear ();
 608         _butler->seek (t, accurate);
 609         get ();
 610
 611         if (was_running) {
 612                 start ();
 613         }
 614
 615         PositionChanged ();
 616 }
 617
 618 void
 619 FilmViewer::config_changed (Config::Property p)
 620 {
 621 #ifdef DCPOMATIC_VARIANT_SWAROOP
 622         if (p == Config::PLAYER_BACKGROUND_IMAGE) {
 623                 refresh_panel ();
 624                 return;
 625         }
 626 #endif
 627
 628         if (p != Config::SOUND && p != Config::SOUND_OUTPUT) {
 629                 return;
 630         }
 631
 632         if (_audio.isStreamOpen ()) {
 633                 _audio.closeStream ();
 634         }
 635
 636         if (Config::instance()->sound() && _audio.getDeviceCount() > 0) {
 637                 unsigned int st = 0;
 638                 if (Config::instance()->sound_output()) {
 639                         while (st < _audio.getDeviceCount()) {
 640                                 if (_audio.getDeviceInfo(st).name == Config::instance()->sound_output().get()) {
 641                                         break;
 642                                 }
 643                                 ++st;
 644                         }
 645                         if (st == _audio.getDeviceCount()) {
 646                                 st = _audio.getDefaultOutputDevice();
 647                         }
 648                 } else {
 649                         st = _audio.getDefaultOutputDevice();
 650                 }
 651
 652                 _audio_channels = _audio.getDeviceInfo(st).outputChannels;
 653
 654                 RtAudio::StreamParameters sp;
 655                 sp.deviceId = st;
 656                 sp.nChannels = _audio_channels;
 657                 sp.firstChannel = 0;
 658                 try {
 659                         _audio.openStream (&sp, 0, RTAUDIO_FLOAT32, 48000, &_audio_block_size, &rtaudio_callback, this);
 660 #ifdef DCPOMATIC_USE_RTERROR
 661                 } catch (RtError& e) {
 662 #else
 663                 } catch (RtAudioError& e) {
 664 #endif
 665                         error_dialog (
 666                                 _panel,
 667                                 _("Could not set up audio output.  There will be no audio during the preview."), std_to_wx(e.what())
 668                                 );
 669                 }
 670                 recreate_butler ();
 671
 672         } else {
 673                 _audio_channels = 0;
 674                 recreate_butler ();
 675         }
 676 }
 677
 678 DCPTime
 679 FilmViewer::uncorrected_time () const
 680 {
 681         if (_audio.isStreamRunning ()) {
 682                 return DCPTime::from_seconds (const_cast<RtAudio*>(&_audio)->getStreamTime());
 683         }
 684
 685         return _video_position;
 686 }
 687
 688 DCPTime
 689 FilmViewer::time () const
 690 {
 691         if (_audio.isStreamRunning ()) {
 692                 return DCPTime::from_seconds (const_cast<RtAudio*>(&_audio)->getStreamTime ()) -
 693                         DCPTime::from_frames (average_latency(), _film->audio_frame_rate());
 694         }
 695
 696         return _video_position;
 697 }
 698
 699 int
 700 FilmViewer::audio_callback (void* out_p, unsigned int frames)
 701 {
 702         while (true) {
 703                 optional<DCPTime> t = _butler->get_audio (reinterpret_cast<float*> (out_p), frames);
 704                 if (!t || DCPTime(uncorrected_time() - *t) < one_video_frame()) {
 705                         /* There was an underrun or this audio is on time; carry on */
 706                         break;
 707                 }
 708                 /* The audio we just got was (very) late; drop it and get some more. */
 709         }
 710
 711         boost::mutex::scoped_lock lm (_latency_history_mutex, boost::try_to_lock);
 712         if (lm) {
 713                 _latency_history.push_back (_audio.getStreamLatency ());
 714                 if (_latency_history.size() > static_cast<size_t> (_latency_history_count)) {
 715                         _latency_history.pop_front ();
 716                 }
 717         }
 718
 719         return 0;
 720 }
 721
 722 Frame
 723 FilmViewer::average_latency () const
 724 {
 725         boost::mutex::scoped_lock lm (_latency_history_mutex);
 726         if (_latency_history.empty()) {
 727                 return 0;
 728         }
 729
 730         Frame total = 0;
 731         BOOST_FOREACH (Frame i, _latency_history) {
 732                 total += i;
 733         }
 734
 735         return total / _latency_history.size();
 736 }
 737
 738 void
 739 FilmViewer::set_dcp_decode_reduction (optional<int> reduction)
 740 {
 741         _dcp_decode_reduction = reduction;
 742         if (_player) {
 743                 _player->set_dcp_decode_reduction (reduction);
 744         }
 745 }
 746
 747 optional<int>
 748 FilmViewer::dcp_decode_reduction () const
 749 {
 750         return _dcp_decode_reduction;
 751 }
 752
 753 DCPTime
 754 FilmViewer::one_video_frame () const
 755 {
 756         return DCPTime::from_frames (1, _film->video_frame_rate());
 757 }
 758
 759 /** Open a dialog box showing our film's closed captions */
 760 void
 761 FilmViewer::show_closed_captions ()
 762 {
 763         _closed_captions_dialog->Show();
 764 }
 765
 766 void
 767 FilmViewer::seek_by (DCPTime by, bool accurate)
 768 {
 769         seek (_video_position + by, accurate);
 770 }
 771
 772 void
 773 FilmViewer::set_pad_black (bool p)
 774 {
 775         _pad_black = p;
 776 }